From 31a408d813adc83bfdb142e4e6bc30c4e8a321e2 Mon Sep 17 00:00:00 2001
From: Rowland <975945824@qq.com>
Date: Mon, 27 Jul 2026 17:02:26 +0800
Subject: [PATCH] =?UTF-8?q?=E5=9C=BA=E6=99=AF=E5=8A=A0=E8=BD=BD=E4=BC=98?=
 =?UTF-8?q?=E5=8C=96?=
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Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 Apps/MetaCorePlayer/main.cpp                  |  50 +-
 CMakeLists.txt                                |  17 +
 .../Private/MetaCoreBuildPipeline.cpp         | 164 ++++-
 .../MetaCoreDelivery/MetaCoreBuildPipeline.h  |   9 +
 .../MetaCoreBuiltinCoreServicesModule.cpp     | 222 ++++++-
 .../Private/MetaCoreBuiltinEditorModule.cpp   |  71 ++-
 .../Private/MetaCoreEditorApp.cpp             |  17 +-
 .../MetaCoreEditorCameraController.cpp        |  18 +-
 .../Private/MetaCoreEditorCameraController.h  |   1 +
 .../MetaCoreSceneInteractionService.cpp       | 130 ++--
 .../Public/MetaCoreEditor/MetaCoreEditorApp.h |   2 +
 .../MetaCoreEditor/MetaCoreEditorContext.h    |   4 +
 .../MetaCoreEditor/MetaCoreEditorServices.h   |   6 +
 .../Private/MetaCoreFilamentSceneBridge.cpp   |  82 ++-
 .../MetaCoreRender/MetaCoreSceneRenderSync.h  |   8 +
 .../MetaCoreScene/Private/MetaCorePrefab.cpp  | 388 ++++++++++++
 .../MetaCoreScene/Private/MetaCoreScene.cpp   |  10 +
 .../Private/MetaCoreScenePackage.cpp          |  23 +-
 .../Private/MetaCoreSceneSerializer.cpp       | 266 ++++++++-
 .../Private/MetaCoreSceneWorld.cpp            | 565 ++++++++++++++++++
 .../Public/MetaCoreScene/MetaCoreComponents.h |   5 +
 .../Public/MetaCoreScene/MetaCoreGameObject.h |  23 +
 .../MetaCoreScene/MetaCoreObjectReference.h   |  30 +
 .../Public/MetaCoreScene/MetaCorePrefab.h     |  64 ++
 .../MetaCoreScene/MetaCoreSceneDocument.h     | 153 +++++
 .../Public/MetaCoreScene/MetaCoreSceneWorld.h | 175 ++++++
 ...etacore-mature-engine-gap-and-work-plan.md |  25 +-
 tests/MetaCoreDeliveryTests.cpp               |  10 +
 tests/MetaCoreSceneBenchmark.cpp              |  81 +++
 tests/MetaCoreSceneTests.cpp                  | 306 ++++++++++
 tests/MetaCoreSmokeTests.cpp                  |  31 +-
 31 files changed, 2812 insertions(+), 144 deletions(-)
 create mode 100644 Source/MetaCoreScene/Private/MetaCorePrefab.cpp
 create mode 100644 Source/MetaCoreScene/Private/MetaCoreSceneWorld.cpp
 create mode 100644 Source/MetaCoreScene/Public/MetaCoreScene/MetaCoreObjectReference.h
 create mode 100644 Source/MetaCoreScene/Public/MetaCoreScene/MetaCorePrefab.h
 create mode 100644 Source/MetaCoreScene/Public/MetaCoreScene/MetaCoreSceneWorld.h
 create mode 100644 tests/MetaCoreSceneBenchmark.cpp
 create mode 100644 tests/MetaCoreSceneTests.cpp

diff --git a/Apps/MetaCorePlayer/main.cpp b/Apps/MetaCorePlayer/main.cpp
index 9ace87b..9b55aad 100644
--- a/Apps/MetaCorePlayer/main.cpp
+++ b/Apps/MetaCorePlayer/main.cpp
@@ -21,6 +21,7 @@
 #include "MetaCoreRuntimeInput/MetaCoreRuntimeInteraction.h"
 #include "MetaCoreScene/MetaCoreScenePackage.h"
 #include "MetaCoreScene/MetaCoreScene.h"
+#include "MetaCoreScene/MetaCoreSceneWorld.h"
 #include "MetaCoreScripting/MetaCoreScripting.h"
 
 #include <filesystem>
@@ -30,6 +31,7 @@
 #include <iostream>
 #include <memory>
 #include <unordered_map>
+#include <thread>
 #include <vector>
 
 namespace {
@@ -450,10 +452,50 @@ int main(int argc, char* argv[]) {
         startupSceneDocument = MetaCore::MetaCoreLoadStartupSceneDocument(projectPath);
     }
     MetaCore::MetaCoreScene scene;
+    std::unordered_map<MetaCore::MetaCoreAssetGuid, std::filesystem::path, MetaCore::MetaCoreAssetGuidHasher> runtimeScenePackages;
+    if (deliveryDocument) for (const auto& entry : deliveryDocument->ScenePackages)
+        runtimeScenePackages[entry.SceneGuid] = packageRoot / entry.PackagePath;
+    MetaCore::MetaCoreSceneWorld sceneWorld(
+        scene,
+        [&](const MetaCore::MetaCoreAssetGuid& sceneGuid) -> std::optional<MetaCore::MetaCoreSceneDocument> {
+            if (const auto path = runtimeScenePackages.find(sceneGuid); path != runtimeScenePackages.end())
+                return MetaCore::MetaCoreReadScenePackage(path->second);
+            if (!deliveryDocument) {
+                std::error_code scanError;
+                const auto scenesRoot = projectRoot / "Scenes";
+                if (std::filesystem::is_directory(scenesRoot, scanError)) {
+                    for (std::filesystem::recursive_directory_iterator iterator(
+                             scenesRoot, std::filesystem::directory_options::skip_permission_denied, scanError), end;
+                         !scanError && iterator != end; iterator.increment(scanError)) {
+                        if (!iterator->is_regular_file(scanError)) continue;
+                        auto candidate = MetaCore::MetaCoreReadScenePackage(iterator->path());
+                        if (candidate && candidate->SceneGuid == sceneGuid) return candidate;
+                    }
+                }
+            }
+            return std::nullopt;
+        }
+    );
     if (startupSceneDocument.has_value()) {
-        MetaCore::MetaCoreSceneSnapshot snapshot;
-        snapshot.GameObjects = startupSceneDocument->GameObjects;
-        scene.RestoreSnapshot(snapshot);
+        std::string sceneLoadError;
+        if (!sceneWorld.LoadDocumentNow(*startupSceneDocument, MetaCore::MetaCoreSceneLoadMode::Replace, &sceneLoadError)) {
+            errors << "MCB6004: startup SceneWorld load failed: " << sceneLoadError << '\n';
+            return 2;
+        }
+        // AlwaysLoaded SubScenes are part of the startup transaction from the
+        // runtime's point of view: settle their background reads before systems scan ECS.
+        const std::size_t expectedStartupScenes = 1U + static_cast<std::size_t>(std::count_if(
+            startupSceneDocument->SubScenes.begin(), startupSceneDocument->SubScenes.end(),
+            [](const auto& subScene) { return subScene.LoadPolicy == MetaCore::MetaCoreSubSceneLoadPolicy::AlwaysLoaded; }
+        ));
+        for (int iteration = 0; iteration < 1000 && sceneWorld.GetLoadedScenes().size() < expectedStartupScenes; ++iteration) {
+            sceneWorld.Tick();
+            std::this_thread::yield();
+        }
+        if (sceneWorld.GetLoadedScenes().size() < expectedStartupScenes) {
+            errors << "MCB6004: one or more AlwaysLoaded SubScenes failed to load\n";
+            return 2;
+        }
         output << "MetaCorePlayer: loaded startup scene from project "
                   << projectPath.string() << '\n';
     } else if (!deliveryDocument) {
@@ -704,6 +746,8 @@ int main(int argc, char* argv[]) {
         MetaCore::MetaCoreSceneView interactionSceneView = MetaCoreBuildPlayerSceneView();
         const auto interactionSnapshot = interactionCameraSync.BuildSnapshot(scene);
         (void)MetaCore::MetaCoreSceneRenderSync::TryBuildSceneViewFromPrimaryCamera(interactionSnapshot, interactionSceneView);
+        sceneWorld.UpdateStreaming({interactionSceneView.CameraPosition});
+        sceneWorld.Tick();
         runtimeInteraction.Update(scene, viewportRenderer, physicsWorld, interactionSceneView,
             window.GetInput(), inputViewport, uiConsumption.Mouse);
         fixedAccumulatorSeconds += std::clamp(frameDeltaSeconds, 0.0, physicsSettings.MaxFrameDelta);
diff --git a/CMakeLists.txt b/CMakeLists.txt
index e86779d..ad996af 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -561,14 +561,19 @@ set(METACORE_SCENE_HEADERS
     Source/MetaCoreScene/Public/MetaCoreScene/MetaCoreComponents.h
     Source/MetaCoreScene/Public/MetaCoreScene/MetaCoreGameObject.h
     Source/MetaCoreScene/Public/MetaCoreScene/MetaCoreSceneDocument.h
+    Source/MetaCoreScene/Public/MetaCoreScene/MetaCoreObjectReference.h
+    Source/MetaCoreScene/Public/MetaCoreScene/MetaCorePrefab.h
     Source/MetaCoreScene/Public/MetaCoreScene/MetaCoreScenePackage.h
     Source/MetaCoreScene/Public/MetaCoreScene/MetaCoreScene.h
+    Source/MetaCoreScene/Public/MetaCoreScene/MetaCoreSceneWorld.h
     Source/MetaCoreScene/Public/MetaCoreScene/MetaCoreSceneSerializer.h
 )
 
 set(METACORE_SCENE_SOURCES
     Source/MetaCoreScene/Private/MetaCoreScenePackage.cpp
     Source/MetaCoreScene/Private/MetaCoreScene.cpp
+    Source/MetaCoreScene/Private/MetaCoreSceneWorld.cpp
+    Source/MetaCoreScene/Private/MetaCorePrefab.cpp
     Source/MetaCoreScene/Private/MetaCoreSceneSerializer.cpp
 )
 
@@ -579,6 +584,7 @@ metacore_generate_reflection(
     Source/MetaCoreScene/Public/MetaCoreScene/MetaCoreComponents.h
     Source/MetaCoreScene/Public/MetaCoreScene/MetaCoreGameObject.h
     Source/MetaCoreScene/Public/MetaCoreScene/MetaCoreSceneDocument.h
+    Source/MetaCoreScene/Public/MetaCoreScene/MetaCoreObjectReference.h
     Source/MetaCoreScene/Public/MetaCoreScene/MetaCoreScene.h
 )
 
@@ -1001,6 +1007,17 @@ metacore_stage_material_templates(MetaCorePlayer)
 if(METACORE_BUILD_TESTS)
     enable_testing()
 
+    add_executable(MetaCoreSceneTests tests/MetaCoreSceneTests.cpp)
+    target_link_libraries(MetaCoreSceneTests PRIVATE MetaCoreScene)
+    target_compile_options(MetaCoreSceneTests PRIVATE ${METACORE_COMMON_WARNINGS})
+    add_test(NAME MetaCoreSceneTests COMMAND MetaCoreSceneTests)
+
+    add_executable(MetaCoreSceneBenchmark tests/MetaCoreSceneBenchmark.cpp)
+    target_link_libraries(MetaCoreSceneBenchmark PRIVATE MetaCoreScene)
+    target_compile_options(MetaCoreSceneBenchmark PRIVATE ${METACORE_COMMON_WARNINGS})
+    add_test(NAME MetaCoreSceneBenchmark COMMAND MetaCoreSceneBenchmark)
+    set_tests_properties(MetaCoreSceneBenchmark PROPERTIES LABELS "benchmark")
+
     add_executable(MetaCoreDeliveryTests
         tests/MetaCoreDeliveryTests.cpp
         Source/MetaCoreRender/Private/MetaCoreGlibcCompat.cpp
diff --git a/Source/MetaCoreDelivery/Private/MetaCoreBuildPipeline.cpp b/Source/MetaCoreDelivery/Private/MetaCoreBuildPipeline.cpp
index 997d3a2..3457ca8 100644
--- a/Source/MetaCoreDelivery/Private/MetaCoreBuildPipeline.cpp
+++ b/Source/MetaCoreDelivery/Private/MetaCoreBuildPipeline.cpp
@@ -12,6 +12,7 @@
 #include "MetaCoreRuntimeData/MetaCoreRuntimeDataProject.h"
 #include "MetaCoreRendering/MetaCoreRendering.h"
 #include "MetaCoreScene/MetaCoreScenePackage.h"
+#include "MetaCoreScene/MetaCorePrefab.h"
 #include "MetaCoreScene/MetaCoreSceneSerializer.h"
 #include "MetaCoreScripting/MetaCoreScripting.h"
 
@@ -30,6 +31,7 @@
 #include <sstream>
 #include <system_error>
 #include <unordered_set>
+#include <unordered_map>
 #if defined(__linux__)
 #include <sys/utsname.h>
 #endif
@@ -562,6 +564,20 @@ std::optional<MetaCoreRuntimeDeliveryDocument> MetaCoreReadRuntimeDeliveryDocume
             if (module.is_string()) document.ScriptModules.emplace_back(module.get<std::string>());
         }
     }
+    if (value->contains("scene_packages") && (*value)["scene_packages"].is_array()) {
+        for (const auto& scene : (*value)["scene_packages"]) {
+            MetaCoreRuntimeDeliveryDocument::SceneEntry entry;
+            entry.SceneGuid = MetaCoreAssetGuid::Parse(scene.value("guid", "")).value_or(MetaCoreAssetGuid{});
+            entry.PackagePath = scene.value("path", "");
+            entry.SourceHash = scene.value("source_hash", std::uint64_t{});
+            if (scene.contains("dependencies")) for (const auto& dependency : scene["dependencies"]) {
+                if (dependency.is_string()) {
+                    if (const auto guid = MetaCoreAssetGuid::Parse(dependency.get<std::string>())) entry.Dependencies.push_back(*guid);
+                }
+            }
+            document.ScenePackages.push_back(std::move(entry));
+        }
+    }
     if (document.FormatVersion != GMetaCoreRuntimeDeliveryVersion) {
         SetIssue(issue, MetaCoreBuildErrorCode::ManifestVersionUnsupported, "Runtime delivery format is unsupported", path);
         return std::nullopt;
@@ -582,18 +598,36 @@ std::optional<MetaCoreRuntimeDeliveryDocument> MetaCoreReadRuntimeDeliveryDocume
             return std::nullopt;
         }
     }
+    for (const auto& scene : document.ScenePackages) {
+        if (!scene.SceneGuid.IsValid() || !IsSafeRelativePath(scene.PackagePath)) {
+            SetIssue(issue, MetaCoreBuildErrorCode::UnsafePath, "Runtime delivery contains an invalid scene entry", path);
+            return std::nullopt;
+        }
+    }
     return document;
 }
 
 bool MetaCoreWriteRuntimeDeliveryDocument(const std::filesystem::path& path, const MetaCoreRuntimeDeliveryDocument& document) {
     json modules = json::array();
     for (const auto& module : document.ScriptModules) modules.push_back(module.generic_string());
+    json scenes = json::array();
+    for (const auto& scene : document.ScenePackages) {
+        json dependencies = json::array();
+        for (const auto& dependency : scene.Dependencies) dependencies.push_back(dependency.ToString());
+        scenes.push_back({
+            {"guid", scene.SceneGuid.ToString()},
+            {"path", scene.PackagePath.generic_string()},
+            {"source_hash", scene.SourceHash},
+            {"dependencies", std::move(dependencies)}
+        });
+    }
     return WriteJson(path, {
         {"format_version", document.FormatVersion}, {"runtime_abi_major", document.RuntimeAbiMajor},
         {"runtime_abi_minor", document.RuntimeAbiMinor}, {"build_id", document.BuildId},
         {"content_root", document.ContentRoot.generic_string()}, {"startup_scene", document.StartupScene.generic_string()},
         {"runtime_config", document.RuntimeConfig.generic_string()}, {"ui_manifest", document.UiManifest.generic_string()},
-        {"release_manifest", document.ReleaseManifest.generic_string()}, {"script_modules", std::move(modules)}
+        {"release_manifest", document.ReleaseManifest.generic_string()}, {"script_modules", std::move(modules)},
+        {"scene_packages", std::move(scenes)}
     });
 }
 
@@ -832,6 +866,7 @@ MetaCoreBuildResult MetaCoreBuildPipeline::Run(const MetaCoreBuildRequest& reque
     MetaCoreRegisterRuntimeDataGeneratedTypes(inputRegistry);
     MetaCoreRegisterRuntimeInputGeneratedTypes(inputRegistry);
     MetaCoreRegisterPhysicsGeneratedTypes(inputRegistry);
+    const MetaCoreTypeRegistry sceneRegistry = MetaCoreBuildScenePackageTypeRegistry();
     const auto runtimeProjectPath = request.ProjectRoot / project->RuntimeDirectory / "ProjectRuntime.mcruntimecfg";
     auto runtimeProject = MetaCoreReadRuntimeProjectDocument(runtimeProjectPath, inputRegistry);
     if (!runtimeProject) return fail(MetaCoreBuildErrorCode::CookFailed, "Runtime project configuration is missing or unreadable", runtimeProjectPath);
@@ -883,6 +918,7 @@ MetaCoreBuildResult MetaCoreBuildPipeline::Run(const MetaCoreBuildRequest& reque
     const auto cookedScene = staging / "Content" / "Scenes" / cookedSceneName;
     const auto cookablePhysicsMeshes = MetaCoreCollectCookablePhysicsMeshes(request.ProjectRoot, inputRegistry, staging / "Content" / "Physics");
     std::optional<MetaCoreSceneDocument> startupSceneDocument;
+    std::vector<MetaCoreRuntimeDeliveryDocument::SceneEntry> stagedSceneEntries;
     if (startupSource.extension() == ".json") {
         const auto registry = MetaCoreBuildScenePackageTypeRegistry();
         const auto scene = MetaCoreSceneSerializer::LoadSceneFromJson(absoluteStartup, registry);
@@ -903,6 +939,131 @@ MetaCoreBuildResult MetaCoreBuildPipeline::Run(const MetaCoreBuildRequest& reque
         std::filesystem::copy_file(absoluteStartup, cookedScene, std::filesystem::copy_options::overwrite_existing, error);
         if (error) return fail(MetaCoreBuildErrorCode::CookFailed, "Failed to copy startup scene", absoluteStartup);
     }
+    if (startupSceneDocument) {
+        if (!startupSceneDocument->SceneGuid.IsValid())
+            return fail(MetaCoreBuildErrorCode::CookFailed, "Startup scene has no stable SceneGuid", absoluteStartup);
+
+        std::unordered_map<MetaCoreAssetGuid, std::filesystem::path, MetaCoreAssetGuidHasher> sceneSources;
+        std::error_code sceneScanError;
+        const auto sceneRoot = request.ProjectRoot / "Scenes";
+        if (std::filesystem::is_directory(sceneRoot, sceneScanError)) {
+            for (std::filesystem::recursive_directory_iterator iterator(
+                     sceneRoot, std::filesystem::directory_options::skip_permission_denied, sceneScanError), end;
+                 !sceneScanError && iterator != end; iterator.increment(sceneScanError)) {
+                if (!iterator->is_regular_file(sceneScanError)) continue;
+                const auto path = iterator->path();
+                if (!path.filename().string().ends_with(".mcscene.json")) continue;
+                if (const auto candidate = MetaCoreSceneSerializer::LoadSceneFromJson(path, sceneRegistry);
+                    candidate && candidate->SceneGuid.IsValid()) {
+                    sceneSources[candidate->SceneGuid] = path;
+                }
+            }
+        }
+        sceneSources[startupSceneDocument->SceneGuid] = absoluteStartup;
+
+        std::unordered_map<MetaCoreAssetGuid, MetaCorePrefabDocument, MetaCoreAssetGuidHasher> prefabDocuments;
+        std::error_code prefabScanError;
+        const auto prefabRoot = request.ProjectRoot / "Assets";
+        if (std::filesystem::is_directory(prefabRoot, prefabScanError)) {
+            for (std::filesystem::recursive_directory_iterator iterator(
+                     prefabRoot, std::filesystem::directory_options::skip_permission_denied, prefabScanError), end;
+                 !prefabScanError && iterator != end; iterator.increment(prefabScanError)) {
+                if (!iterator->is_regular_file(prefabScanError) ||
+                    !iterator->path().filename().string().ends_with(".mcprefab.json")) continue;
+                if (auto prefab = MetaCoreSceneSerializer::LoadPrefabFromJson(iterator->path(), sceneRegistry);
+                    prefab && prefab->PrefabGuid.IsValid())
+                    prefabDocuments[prefab->PrefabGuid] = std::move(*prefab);
+            }
+        }
+        MetaCorePrefabResolver prefabResolver(
+            [&](const MetaCoreAssetGuid& guid) -> std::optional<MetaCorePrefabDocument> {
+                const auto iterator = prefabDocuments.find(guid);
+                return iterator == prefabDocuments.end() ? std::nullopt : std::optional(iterator->second);
+            }
+        );
+
+        std::unordered_set<MetaCoreAssetGuid, MetaCoreAssetGuidHasher> visitedScenes;
+        std::unordered_set<MetaCoreAssetGuid, MetaCoreAssetGuidHasher> activeScenes;
+        std::string sceneDependencyError;
+        std::function<bool(
+            const MetaCoreSceneDocument&,
+            const std::filesystem::path&,
+            const std::filesystem::path&
+        )> stageSceneClosure;
+        stageSceneClosure = [&](const MetaCoreSceneDocument& sceneDocument,
+                                const std::filesystem::path& sourcePath,
+                                const std::filesystem::path& outputPath) {
+            if (visitedScenes.contains(sceneDocument.SceneGuid)) return true;
+            if (!activeScenes.insert(sceneDocument.SceneGuid).second) {
+                sceneDependencyError = "SubScene dependency cycle at " + sceneDocument.SceneGuid.ToString();
+                return false;
+            }
+            for (const auto& instance : sceneDocument.PrefabInstances) {
+                const auto prefabIssues = prefabResolver.ValidateDependencies(instance.PrefabAssetGuid);
+                if (!prefabIssues.empty()) {
+                    sceneDependencyError = "Prefab dependency validation failed for " +
+                        instance.PrefabAssetGuid.ToString() + ": " + prefabIssues.front();
+                    return false;
+                }
+            }
+            std::vector<MetaCoreAssetGuid> dependencies;
+            for (const auto& subScene : sceneDocument.SubScenes)
+                if (subScene.SceneGuid.IsValid()) dependencies.push_back(subScene.SceneGuid);
+            for (const auto& object : sceneDocument.GameObjects) {
+                if (object.PhysicsConstraint &&
+                    object.PhysicsConstraint->TargetObjectReference.Strength == MetaCoreObjectReferenceStrength::Hard &&
+                    object.PhysicsConstraint->TargetObjectReference.SceneGuid.IsValid())
+                    dependencies.push_back(object.PhysicsConstraint->TargetObjectReference.SceneGuid);
+                if (object.TimelineDirector) for (const auto& binding : object.TimelineDirector->Bindings)
+                    if (binding.ObjectReference.Strength == MetaCoreObjectReferenceStrength::Hard &&
+                        binding.ObjectReference.SceneGuid.IsValid())
+                        dependencies.push_back(binding.ObjectReference.SceneGuid);
+            }
+            std::sort(dependencies.begin(), dependencies.end(), [](const auto& lhs, const auto& rhs) {
+                return lhs.ToString() < rhs.ToString();
+            });
+            dependencies.erase(std::unique(dependencies.begin(), dependencies.end()), dependencies.end());
+            for (const auto& dependency : dependencies) {
+                if (dependency == sceneDocument.SceneGuid) continue;
+                auto source = sceneSources.find(dependency);
+                if (source == sceneSources.end()) {
+                    const auto declared = std::find_if(sceneDocument.SubScenes.begin(), sceneDocument.SubScenes.end(),
+                        [&](const auto& subScene) { return subScene.SceneGuid == dependency && !subScene.ScenePath.empty(); });
+                    if (declared != sceneDocument.SubScenes.end() && IsSafeRelativePath(declared->ScenePath))
+                        source = sceneSources.emplace(dependency, request.ProjectRoot / declared->ScenePath).first;
+                }
+                if (source == sceneSources.end() || !std::filesystem::is_regular_file(source->second)) {
+                    sceneDependencyError = "Required Scene dependency is missing: " + dependency.ToString();
+                    return false;
+                }
+                auto dependencyDocument = source->second.extension() == ".json"
+                    ? MetaCoreSceneSerializer::LoadSceneFromJson(source->second, sceneRegistry)
+                    : MetaCoreReadScenePackage(source->second);
+                if (!dependencyDocument || dependencyDocument->SceneGuid != dependency) {
+                    sceneDependencyError = "Scene dependency GUID/path mismatch: " + dependency.ToString();
+                    return false;
+                }
+                const auto relativeOutput = std::filesystem::path("Content") / "Scenes" /
+                    (dependency.ToString() + ".mcscene");
+                if (!stageSceneClosure(*dependencyDocument, source->second, staging / relativeOutput)) return false;
+            }
+            if (outputPath != cookedScene && !MetaCoreWriteScenePackage(outputPath, sceneDocument)) {
+                sceneDependencyError = "Failed to cook dependent Scene: " + sourcePath.string();
+                return false;
+            }
+            stagedSceneEntries.push_back({
+                sceneDocument.SceneGuid,
+                outputPath.lexically_relative(staging),
+                MetaCoreHashFile(sourcePath).value_or(0),
+                dependencies
+            });
+            activeScenes.erase(sceneDocument.SceneGuid);
+            visitedScenes.insert(sceneDocument.SceneGuid);
+            return true;
+        };
+        if (!stageSceneClosure(*startupSceneDocument, absoluteStartup, cookedScene))
+            return fail(MetaCoreBuildErrorCode::DependencyMissing, sceneDependencyError, absoluteStartup);
+    }
     const auto currentCookRoot = request.ProjectRoot / "Library" / "Cooked" / profile->TargetPlatform / profile->Name;
     const auto editorCookRoot = request.ProjectRoot / "Library" / "Cooked" / profile->TargetPlatform / "Editor";
     const auto legacyCookRoot = request.ProjectRoot / "Library" / "Cooked" / "Windows";
@@ -1036,6 +1197,7 @@ MetaCoreBuildResult MetaCoreBuildPipeline::Run(const MetaCoreBuildRequest& reque
     MetaCoreRuntimeDeliveryDocument delivery;
     delivery.BuildId = result.BuildId;
     delivery.StartupScene = std::filesystem::path("Content") / "Scenes" / cookedSceneName;
+    delivery.ScenePackages = stagedSceneEntries;
     if (!stagedScriptModule.empty()) delivery.ScriptModules.push_back(std::filesystem::path("Project") / "Scripts" / stagedScriptModule.filename());
     if (!MetaCoreWriteRuntimeDeliveryDocument(staging / "Project" / "MetaCore.runtimeproject", delivery))
         return fail(MetaCoreBuildErrorCode::StageFailed, "Failed to write runtime project document", staging);
diff --git a/Source/MetaCoreDelivery/Public/MetaCoreDelivery/MetaCoreBuildPipeline.h b/Source/MetaCoreDelivery/Public/MetaCoreDelivery/MetaCoreBuildPipeline.h
index 44c509b..29cc8d5 100644
--- a/Source/MetaCoreDelivery/Public/MetaCoreDelivery/MetaCoreBuildPipeline.h
+++ b/Source/MetaCoreDelivery/Public/MetaCoreDelivery/MetaCoreBuildPipeline.h
@@ -1,5 +1,7 @@
 #pragma once
 
+#include "MetaCoreFoundation/MetaCoreAssetGuid.h"
+
 #include <atomic>
 #include <cstdint>
 #include <filesystem>
@@ -62,6 +64,13 @@ struct MetaCoreRuntimeDeliveryDocument {
     std::filesystem::path UiManifest = "Content/Runtime/Ui.mcruntime";
     std::filesystem::path ReleaseManifest = "Manifest/MetaCore.release.json";
     std::vector<std::filesystem::path> ScriptModules{};
+    struct SceneEntry {
+        MetaCoreAssetGuid SceneGuid{};
+        std::filesystem::path PackagePath{};
+        std::uint64_t SourceHash = 0;
+        std::vector<MetaCoreAssetGuid> Dependencies{};
+    };
+    std::vector<SceneEntry> ScenePackages{};
 };
 
 struct MetaCoreReleaseFileEntry {
diff --git a/Source/MetaCoreEditor/Private/MetaCoreBuiltinCoreServicesModule.cpp b/Source/MetaCoreEditor/Private/MetaCoreBuiltinCoreServicesModule.cpp
index ab5a362..b0dac1c 100644
--- a/Source/MetaCoreEditor/Private/MetaCoreBuiltinCoreServicesModule.cpp
+++ b/Source/MetaCoreEditor/Private/MetaCoreBuiltinCoreServicesModule.cpp
@@ -26,6 +26,8 @@
 #include "MetaCoreFoundation/MetaCoreRuntimeAssetRegistry.h"
 #include "MetaCoreScene/MetaCoreScenePackage.h"
 #include "MetaCoreScene/MetaCoreSceneSerializer.h"
+#include "MetaCoreScene/MetaCoreSceneWorld.h"
+#include "MetaCoreScene/MetaCorePrefab.h"
 #include <nlohmann/json.hpp>
 
 #include <imgui.h>
@@ -9869,6 +9871,7 @@ public:
         CurrentSceneGuid_ = MetaCoreAssetGuid{};
         CurrentScenePath_.clear();
         CurrentSceneName_.clear();
+        ScenePaths_.clear();
         SavedSnapshotBytes_.clear();
         Dirty_ = false;
     }
@@ -9893,6 +9896,18 @@ public:
     }
 
     bool LoadScene(MetaCoreEditorContext& editorContext, const std::filesystem::path& relativeScenePath) override {
+        return LoadSceneWithMode(editorContext, relativeScenePath, MetaCoreSceneLoadMode::Replace);
+    }
+
+    bool LoadSceneAdditive(MetaCoreEditorContext& editorContext, const std::filesystem::path& relativeScenePath) override {
+        return LoadSceneWithMode(editorContext, relativeScenePath, MetaCoreSceneLoadMode::Additive);
+    }
+
+    bool LoadSceneWithMode(
+        MetaCoreEditorContext& editorContext,
+        const std::filesystem::path& relativeScenePath,
+        MetaCoreSceneLoadMode loadMode
+    ) {
         if (AssetDatabaseService_ == nullptr ||
             ReflectionRegistry_ == nullptr ||
             !AssetDatabaseService_->HasProject() ||
@@ -9944,15 +9959,12 @@ public:
             if(!migrationFailed)for(const auto&change:pending){auto&animator=*sceneDocument->GameObjects[change.ObjectIndex].Animator;animator.ControllerAssetGuid=change.Controller;animator.AvatarAssetGuid=change.Avatar;migratedLegacyAnimators=true;}
         }
 
-        MetaCoreEditorStateSnapshot editorStateSnapshot;
-        editorStateSnapshot.SceneSnapshot.Environment = sceneDocument->Environment;
-        editorStateSnapshot.SceneSnapshot.GameObjects = sceneDocument->GameObjects;
-        editorStateSnapshot.SelectionSnapshot = sceneDocument->Selection;
-        editorContext.RestoreStateSnapshot(editorStateSnapshot);
-        editorContext.GetCommandService().Clear();
-
         // 从 .meta 提取或生成 Guid
-        MetaCoreAssetGuid sceneGuid{};
+        MetaCoreAssetGuid sceneGuid = sceneDocument->SceneGuid;
+        if (const auto record = AssetDatabaseService_->FindAssetByRelativePath(normalizedScenePath);
+            record.has_value() && record->Guid.IsValid()) {
+            sceneGuid = record->Guid;
+        }
         const std::filesystem::path metaPath = absoluteScenePath.string() + ".meta";
         if (std::filesystem::exists(metaPath)) {
             sceneGuid = MetaCoreAssetRegistry::Get().ResolvePathToGuid(normalizedScenePath);
@@ -9960,12 +9972,42 @@ public:
         if (!sceneGuid.IsValid()) {
             sceneGuid = MetaCoreAssetGuid::Generate();
         }
+        sceneDocument->SceneGuid = sceneGuid;
+        for (auto& object : sceneDocument->GameObjects) object.SceneGuid = sceneGuid;
+
+        if (MetaCoreSceneWorld* world = editorContext.GetSceneWorld()) {
+            world->SetSceneLoader([this](const MetaCoreAssetGuid& guid) -> std::optional<MetaCoreSceneDocument> {
+                if (AssetDatabaseService_ == nullptr || ReflectionRegistry_ == nullptr || !AssetDatabaseService_->HasProject())
+                    return std::nullopt;
+                const auto record = AssetDatabaseService_->FindAssetByGuid(guid);
+                if (!record) return std::nullopt;
+                const auto relative = !record->PackagePath.empty() ? record->PackagePath : record->RelativePath;
+                const auto absolute = AssetDatabaseService_->GetProjectDescriptor().RootPath / relative;
+                if (relative.extension() == ".mcscene") {
+                    if (auto package = MetaCoreReadScenePackage(absolute)) return package;
+                }
+                return MetaCoreSceneSerializer::LoadSceneFromJson(absolute, ReflectionRegistry_->GetTypeRegistry());
+            });
+            std::string loadError;
+            if (!world->LoadDocumentNow(*sceneDocument, loadMode, &loadError)) {
+                editorContext.AddConsoleMessage(MetaCoreLogLevel::Error, "Scene", "场景组合加载失败: " + loadError);
+                return false;
+            }
+        } else {
+            MetaCoreEditorStateSnapshot editorStateSnapshot;
+            editorStateSnapshot.SceneSnapshot.Environment = sceneDocument->Environment;
+            editorStateSnapshot.SceneSnapshot.GameObjects = sceneDocument->GameObjects;
+            editorStateSnapshot.SelectionSnapshot = sceneDocument->Selection;
+            editorContext.RestoreStateSnapshot(editorStateSnapshot);
+        }
+        editorContext.GetCommandService().Clear();
 
         CurrentSceneGuid_ = sceneGuid;
         CurrentScenePath_ = normalizedScenePath;
         CurrentSceneName_ = sceneDocument->Name.empty()
             ? MetaCoreSceneDisplayNameFromPath(normalizedScenePath)
             : sceneDocument->Name;
+        ScenePaths_[sceneGuid] = normalizedScenePath;
         SavedSnapshotBytes_ = MetaCoreSerializeSceneSnapshotBytes(
             ReflectionRegistry_->GetTypeRegistry(),
             editorContext.GetScene().CaptureSnapshot()
@@ -9986,6 +10028,30 @@ public:
         return true;
     }
 
+    bool UnloadScene(MetaCoreEditorContext& editorContext, const MetaCoreAssetGuid& sceneGuid, bool force) override {
+        MetaCoreSceneWorld* world = editorContext.GetSceneWorld();
+        if (world == nullptr || !world->UnloadScene(sceneGuid, force)) return false;
+        ScenePaths_.erase(sceneGuid);
+        if (CurrentSceneGuid_ == sceneGuid) {
+            CurrentSceneGuid_ = world->GetActiveSceneGuid();
+            const auto path = ScenePaths_.find(CurrentSceneGuid_);
+            CurrentScenePath_ = path == ScenePaths_.end() ? std::filesystem::path{} : path->second;
+            CurrentSceneName_ = CurrentScenePath_.stem().string();
+        }
+        editorContext.ClearSelection();
+        return true;
+    }
+
+    bool SetActiveScene(MetaCoreEditorContext& editorContext, const MetaCoreAssetGuid& sceneGuid) override {
+        MetaCoreSceneWorld* world = editorContext.GetSceneWorld();
+        if (world == nullptr || !world->SetActiveScene(sceneGuid)) return false;
+        CurrentSceneGuid_ = sceneGuid;
+        const auto path = ScenePaths_.find(sceneGuid);
+        CurrentScenePath_ = path == ScenePaths_.end() ? std::filesystem::path{} : path->second;
+        CurrentSceneName_ = CurrentScenePath_.stem().string();
+        return true;
+    }
+
     bool SaveCurrentScene(MetaCoreEditorContext& editorContext) override {
         return CurrentScenePath_.empty()
             ? SaveSceneAs(editorContext, std::filesystem::path("Scenes") / "Untitled.mcscene.json")
@@ -10019,9 +10085,17 @@ public:
 
         MetaCoreSceneDocument sceneDocument;
         sceneDocument.Name = CurrentSceneName_.empty() ? MetaCoreSceneDisplayNameFromPath(normalizedScenePath) : CurrentSceneName_;
-        const MetaCoreSceneSnapshot sceneSnapshot = editorContext.GetScene().CaptureSnapshot();
-        sceneDocument.Environment = sceneSnapshot.Environment;
-        sceneDocument.GameObjects = sceneSnapshot.GameObjects;
+        if (MetaCoreSceneWorld* world = editorContext.GetSceneWorld(); world != nullptr && CurrentSceneGuid_.IsValid()) {
+            const auto captured = world->CaptureSceneDocument(CurrentSceneGuid_);
+            if (!captured) return false;
+            sceneDocument = *captured;
+            sceneDocument.Name = CurrentSceneName_.empty() ? MetaCoreSceneDisplayNameFromPath(normalizedScenePath) : CurrentSceneName_;
+        } else {
+            const MetaCoreSceneSnapshot sceneSnapshot = editorContext.GetScene().CaptureSnapshot();
+            sceneDocument.Environment = sceneSnapshot.Environment;
+            sceneDocument.GameObjects = sceneSnapshot.GameObjects;
+        }
+        sceneDocument.SceneGuid = sceneGuid;
         sceneDocument.Selection.SelectedObjectIds = editorContext.GetSelectedObjectIds();
         sceneDocument.Selection.ActiveObjectId = editorContext.GetActiveObjectId();
         sceneDocument.Selection.SelectionAnchorId = editorContext.GetSelectionAnchorId();
@@ -10047,6 +10121,7 @@ public:
         CurrentSceneGuid_ = sceneGuid;
         CurrentScenePath_ = normalizedScenePath;
         CurrentSceneName_ = sceneDocument.Name;
+        ScenePaths_[sceneGuid] = normalizedScenePath;
         SavedSnapshotBytes_ = MetaCoreSerializeSceneSnapshotBytes(
             ReflectionRegistry_->GetTypeRegistry(),
             editorContext.GetScene().CaptureSnapshot()
@@ -10072,6 +10147,24 @@ public:
         return true;
     }
 
+    bool SaveAllScenes(MetaCoreEditorContext& editorContext) override {
+        MetaCoreSceneWorld* world = editorContext.GetSceneWorld();
+        if (world == nullptr) return SaveCurrentScene(editorContext);
+        const MetaCoreAssetGuid previous = world->GetActiveSceneGuid();
+        bool success = true;
+        const auto paths = ScenePaths_;
+        for (const auto& [guid, path] : paths) {
+            if (!SetActiveScene(editorContext, guid) || path.empty() || !SaveSceneAs(editorContext, path)) success = false;
+        }
+        if (previous.IsValid()) (void)SetActiveScene(editorContext, previous);
+        return success;
+    }
+
+    [[nodiscard]] std::vector<MetaCoreLoadedSceneInfo> GetOpenScenes(const MetaCoreEditorContext& editorContext) const override {
+        const MetaCoreSceneWorld* world = editorContext.GetSceneWorld();
+        return world == nullptr ? std::vector<MetaCoreLoadedSceneInfo>{} : world->GetLoadedScenes();
+    }
+
     void UpdateDirtyState(const MetaCoreSceneSnapshot& snapshot) override {
         if (ReflectionRegistry_ == nullptr) {
             SetDirtyState(true);
@@ -10111,6 +10204,7 @@ private:
     std::string CurrentSceneName_{};
     std::vector<std::byte> SavedSnapshotBytes_{};
     bool Dirty_ = false;
+    std::unordered_map<MetaCoreAssetGuid, std::filesystem::path, MetaCoreAssetGuidHasher> ScenePaths_{};
 };
 
 class MetaCoreBuiltinSelectionService final : public MetaCoreISelectionService {
@@ -11420,6 +11514,7 @@ public:
         State_ = MetaCorePlayModeState::Edit;
         HasPrePlaySnapshot_ = false;
         HasPendingStopRestoreSnapshot_ = false;
+        HasPrePlayWorldSnapshot_ = false;
         CommandRecordingSuppressed_ = false;
         ElapsedTimeSeconds_ = 0.0;
         FixedTimeAccumulatorSeconds_ = 0.0;
@@ -11456,6 +11551,12 @@ public:
         }
         PrePlaySnapshot_ = editorContext.CaptureStateSnapshot();
         HasPrePlaySnapshot_ = true;
+        if (const MetaCoreSceneWorld* world = editorContext.GetSceneWorld()) {
+            PrePlayWorldSnapshot_ = world->CaptureWorldSnapshot();
+            HasPrePlayWorldSnapshot_ = true;
+        } else {
+            HasPrePlayWorldSnapshot_ = false;
+        }
         MetaCoreDebugLog(
             "PlayMode",
             "Enter captured prePlaySnapshot objects=" +
@@ -11709,6 +11810,12 @@ private:
                 " " + MetaCoreDebugSceneSummary(editorContext)
         );
         editorContext.RestoreStateSnapshot(PendingStopRestoreSnapshot_);
+        if (HasPrePlayWorldSnapshot_) {
+            if (MetaCoreSceneWorld* world = editorContext.GetSceneWorld())
+                world->RestoreWorldSnapshot(PrePlayWorldSnapshot_);
+            HasPrePlayWorldSnapshot_ = false;
+            PrePlayWorldSnapshot_ = {};
+        }
         HasPendingStopRestoreSnapshot_ = false;
         PendingStopRestoreSnapshot_ = {};
         MetaCoreDebugLog("PlayMode", "Apply pending stop restore end " + MetaCoreDebugSceneSummary(editorContext));
@@ -11718,8 +11825,10 @@ private:
     MetaCorePlayModeState State_ = MetaCorePlayModeState::Edit;
     MetaCoreEditorStateSnapshot PrePlaySnapshot_{};
     MetaCoreEditorStateSnapshot PendingStopRestoreSnapshot_{};
+    MetaCoreSceneWorldSnapshot PrePlayWorldSnapshot_{};
     bool HasPrePlaySnapshot_ = false;
     bool HasPendingStopRestoreSnapshot_ = false;
+    bool HasPrePlayWorldSnapshot_ = false;
     bool CommandRecordingSuppressed_ = false;
     double ElapsedTimeSeconds_ = 0.0;
     double FixedTimeStepSeconds_ = 1.0 / 60.0;
@@ -11837,6 +11946,7 @@ std::optional<std::filesystem::path> MetaCoreBuiltinPrefabService::CreatePrefabF
     }
 
     MetaCorePrefabDocument prefabDocument;
+    prefabDocument.PrefabGuid = prefabGuid;
     prefabDocument.Name = rootObject ? rootObject.GetName() : normalizedPrefabPath.stem().string();
 
     std::vector<MetaCoreGameObjectData> prefabDataObjects;
@@ -11844,6 +11954,7 @@ std::optional<std::filesystem::path> MetaCoreBuiltinPrefabService::CreatePrefabF
     for (const MetaCoreGameObject& gameObject : prefabObjects) {
         MetaCoreGameObjectData data;
         data.Id = gameObject.GetId();
+        data.StableObjectGuid = MetaCoreBuildDeterministicGuid(prefabGuid, data.Id);
         data.Name = gameObject.GetName();
         data.ParentId = gameObject.GetParentId();
         data.Transform = gameObject.GetComponent<MetaCoreTransformComponent>();
@@ -11902,6 +12013,10 @@ std::optional<MetaCoreId> MetaCoreBuiltinPrefabService::InstantiatePrefabDocumen
     }
 
     MetaCoreId instantiatedRootId = 0;
+    const MetaCoreAssetGuid instanceGuid = MetaCoreAssetGuid::Generate();
+    const MetaCoreAssetGuid targetSceneGuid = editorContext.GetSceneWorld() != nullptr
+        ? editorContext.GetSceneWorld()->GetActiveSceneGuid()
+        : MetaCoreAssetGuid{};
     const bool created = editorContext.ExecuteSnapshotCommand("实例化 Prefab", [&]() {
         std::unordered_map<MetaCoreId, MetaCoreId> idMap;
         std::vector<MetaCoreGameObject> clonedObjects;
@@ -11925,6 +12040,17 @@ std::optional<MetaCoreId> MetaCoreBuiltinPrefabService::InstantiatePrefabDocumen
             }
 
             clonedObject.GetComponent<MetaCoreTransformComponent>() = sourceObject.Transform;
+            if (targetSceneGuid.IsValid()) {
+                const MetaCoreAssetGuid nodeGuid = sourceObject.StableObjectGuid.IsValid()
+                    ? sourceObject.StableObjectGuid
+                    : MetaCoreBuildDeterministicGuid(prefabAssetGuid, sourceObject.Id);
+                clonedObject.AddComponent<MetaCoreSceneObjectIdentityComponent>(
+                    MetaCoreSceneObjectIdentityComponent{
+                        targetSceneGuid,
+                        MetaCoreBuildDeterministicGuid(instanceGuid, nodeGuid)
+                    }
+                );
+            }
             if (sourceObject.Camera.has_value()) clonedObject.AddComponent<MetaCoreCameraComponent>(*sourceObject.Camera);
             if (sourceObject.Light.has_value()) clonedObject.AddComponent<MetaCoreLightComponent>(*sourceObject.Light);
             if (sourceObject.Rotator.has_value()) clonedObject.AddComponent<MetaCoreRotatorComponent>(*sourceObject.Rotator);
@@ -11942,11 +12068,14 @@ std::optional<MetaCoreId> MetaCoreBuiltinPrefabService::InstantiatePrefabDocumen
             if (sourceObject.DecalProjector.has_value()) clonedObject.AddComponent<MetaCoreDecalProjectorComponent>(*sourceObject.DecalProjector);
             if (sourceObject.Terrain.has_value()) clonedObject.AddComponent<MetaCoreTerrainComponent>(*sourceObject.Terrain);
 
-            clonedObject.AddComponent<MetaCorePrefabInstanceMetadata>(MetaCorePrefabInstanceMetadata{
-                prefabAssetGuid,
-                sourceObject.Id,
-                0
-            });
+            MetaCorePrefabInstanceMetadata metadata;
+            metadata.PrefabAssetGuid = prefabAssetGuid;
+            metadata.PrefabObjectId = sourceObject.Id;
+            metadata.InstanceGuid = instanceGuid;
+            metadata.PrefabNodeGuid = sourceObject.StableObjectGuid.IsValid()
+                ? sourceObject.StableObjectGuid
+                : MetaCoreBuildDeterministicGuid(prefabAssetGuid, sourceObject.Id);
+            clonedObject.AddComponent<MetaCorePrefabInstanceMetadata>(metadata);
         }
 
         for (MetaCoreGameObject& clonedObject : clonedObjects) {
@@ -11981,7 +12110,23 @@ std::optional<MetaCoreId> MetaCoreBuiltinPrefabService::InstantiatePrefab(
     if (!prefabDocument.has_value()) {
         return std::nullopt;
     }
-    return InstantiatePrefabDocument(editorContext, prefabAssetGuid, *prefabDocument, forcedParentId);
+    MetaCorePrefabResolver resolver([this](const MetaCoreAssetGuid& guid) {
+        return LoadPrefabDocument(guid);
+    });
+    std::string resolveError;
+    const auto resolved = resolver.Resolve(prefabAssetGuid, &resolveError);
+    if (!resolved) {
+        editorContext.AddConsoleMessage(MetaCoreLogLevel::Error, "Prefab", "Prefab 依赖解析失败: " + resolveError);
+        return std::nullopt;
+    }
+    if (!resolved->OrphanOverrides.empty()) {
+        editorContext.AddConsoleMessage(
+            MetaCoreLogLevel::Warning,
+            "Prefab",
+            "Prefab 包含 " + std::to_string(resolved->OrphanOverrides.size()) + " 个孤立 Override"
+        );
+    }
+    return InstantiatePrefabDocument(editorContext, prefabAssetGuid, resolved->Document, forcedParentId);
 }
 
 bool MetaCoreBuiltinPrefabService::ApplySelectedPrefabInstance(MetaCoreEditorContext& editorContext) {
@@ -12198,6 +12343,11 @@ std::optional<MetaCoreId> MetaCoreBuiltinSceneEditingService::CreateGameObject(
         }
 
         MetaCoreGameObject object = editorContext.GetScene().CreateGameObject(objectName, parentId);
+        if (MetaCoreSceneWorld* world = editorContext.GetSceneWorld(); world != nullptr && world->GetActiveSceneGuid().IsValid()) {
+            object.AddComponent<MetaCoreSceneObjectIdentityComponent>(MetaCoreSceneObjectIdentityComponent{
+                world->GetActiveSceneGuid(), MetaCoreAssetGuid::Generate()
+            });
+        }
         if (withMeshRenderer) {
             auto& meshRenderer = object.AddComponent<MetaCoreMeshRendererComponent>(MetaCoreMeshRendererComponent{});
             if (objectName == "Plane") {
@@ -12251,6 +12401,11 @@ std::optional<MetaCoreId> MetaCoreBuiltinSceneEditingService::CreateCamera(
         }
 
         MetaCoreGameObject cameraObject = editorContext.GetScene().CreateGameObject("Camera", parentId);
+        if (MetaCoreSceneWorld* world = editorContext.GetSceneWorld(); world != nullptr && world->GetActiveSceneGuid().IsValid()) {
+            cameraObject.AddComponent<MetaCoreSceneObjectIdentityComponent>(MetaCoreSceneObjectIdentityComponent{
+                world->GetActiveSceneGuid(), MetaCoreAssetGuid::Generate()
+            });
+        }
         MetaCoreCameraComponent& camera = cameraObject.AddComponent<MetaCoreCameraComponent>(MetaCoreCameraComponent{});
         camera.IsPrimary = !hasEnabledPrimaryCamera;
 
@@ -12388,6 +12543,11 @@ std::optional<MetaCoreId> MetaCoreBuiltinSceneEditingService::InstantiateModelAs
                        ? resolvedModelPath.filename().generic_string()
                        : assetRecord->RelativePath.filename().generic_string());
         MetaCoreGameObject modelRootObject = editorContext.GetScene().CreateGameObject(modelRootName, externalParentId);
+        if (MetaCoreSceneWorld* world = editorContext.GetSceneWorld(); world != nullptr && world->GetActiveSceneGuid().IsValid()) {
+            modelRootObject.AddComponent<MetaCoreSceneObjectIdentityComponent>(MetaCoreSceneObjectIdentityComponent{
+                world->GetActiveSceneGuid(), MetaCoreAssetGuid::Generate()
+            });
+        }
         instantiatedRootId = modelRootObject.GetId();
 
         std::vector<MetaCoreId> nodeToIdMap(importedDocument->Nodes.size(), 0);
@@ -12479,6 +12639,11 @@ std::optional<MetaCoreId> MetaCoreBuiltinSceneEditingService::InstantiateModelAs
             for (std::size_t i = 0; i < importedDocument->Nodes.size(); ++i) {
                 const auto& nodeMeta = importedDocument->Nodes[i];
                 MetaCoreGameObject gameObject = editorContext.GetScene().CreateGameObject(nodeMeta.Name, 0);
+                if (MetaCoreSceneWorld* world = editorContext.GetSceneWorld(); world != nullptr && world->GetActiveSceneGuid().IsValid()) {
+                    gameObject.AddComponent<MetaCoreSceneObjectIdentityComponent>(MetaCoreSceneObjectIdentityComponent{
+                        world->GetActiveSceneGuid(), MetaCoreAssetGuid::Generate()
+                    });
+                }
                 nodeToIdMap[i] = gameObject.GetId();
 
                 // 立即同步变换组件
@@ -12590,6 +12755,29 @@ bool MetaCoreBuiltinSceneEditingService::ReparentSelection(MetaCoreEditorContext
         return false;
     }
 
+    MetaCoreAssetGuid targetSceneGuid{};
+    if (newParentId != 0) {
+        const auto parent = editorContext.GetScene().FindGameObject(newParentId);
+        if (parent && parent.HasComponent<MetaCoreSceneObjectIdentityComponent>()) {
+            targetSceneGuid = parent.GetComponent<MetaCoreSceneObjectIdentityComponent>().SceneGuid;
+        }
+    }
+    for (MetaCoreId selectedId : selectedIds) {
+        const auto selected = editorContext.GetScene().FindGameObject(selectedId);
+        if (!selected || !selected.HasComponent<MetaCoreSceneObjectIdentityComponent>()) {
+            continue;
+        }
+        const auto selectedScene = selected.GetComponent<MetaCoreSceneObjectIdentityComponent>().SceneGuid;
+        if (targetSceneGuid.IsValid() && selectedScene.IsValid() && targetSceneGuid != selectedScene) {
+            editorContext.AddConsoleMessage(
+                MetaCoreLogLevel::Warning,
+                "Hierarchy",
+                "禁止跨场景父子关系；请使用 Move Subtree To Scene"
+            );
+            return false;
+        }
+    }
+
     const bool keepWorldTransform = editorContext.GetReparentTransformRule() == MetaCoreReparentTransformRule::KeepWorld;
     const bool reparented = editorContext.ExecuteSnapshotCommand("重挂接对象", [&]() {
         return editorContext.GetScene().ReparentGameObjects(selectedIds, newParentId, keepWorldTransform);
diff --git a/Source/MetaCoreEditor/Private/MetaCoreBuiltinEditorModule.cpp b/Source/MetaCoreEditor/Private/MetaCoreBuiltinEditorModule.cpp
index e10b549..526bba8 100644
--- a/Source/MetaCoreEditor/Private/MetaCoreBuiltinEditorModule.cpp
+++ b/Source/MetaCoreEditor/Private/MetaCoreBuiltinEditorModule.cpp
@@ -2829,23 +2829,48 @@ static std::array<char, 256> GProjectRenamePathBuffer{};
             BeginRename(editorContext, requestedRenameId);
         }
 
-        ImGui::PushStyleVar(ImGuiStyleVar_ItemSpacing, ImVec2(4, 8));
-        ImGui::TextColored(ImVec4(0.4F, 0.6F, 1.0F, 1.0F), " (S) "); 
-        ImGui::SameLine();
-        const std::string sceneLabel =
-            scenePersistenceService != nullptr && scenePersistenceService->HasOpenScene()
-                ? scenePersistenceService->GetCurrentSceneDisplayName()
-                : "Untitled";
-        ImGui::TextUnformatted(sceneLabel.c_str());
-        if (scenePersistenceService != nullptr && scenePersistenceService->IsSceneDirty()) {
-            ImGui::SameLine();
-            ImGui::TextColored(ImVec4(0.90F, 0.74F, 0.22F, 1.0F), "*");
-        }
-        ImGui::PopStyleVar();
-        ImGui::Separator();
-
-        for (MetaCoreId rootId : editorContext.GetScene().GetRootObjectIds()) {
-            DrawHierarchyNode(editorContext, rootId);
+        const auto openScenes = scenePersistenceService != nullptr
+            ? scenePersistenceService->GetOpenScenes(editorContext)
+            : std::vector<MetaCoreLoadedSceneInfo>{};
+        if (!openScenes.empty()) {
+            for (const auto& loadedScene : openScenes) {
+                ImGuiTreeNodeFlags sceneFlags = ImGuiTreeNodeFlags_DefaultOpen |
+                    ImGuiTreeNodeFlags_SpanFullWidth | ImGuiTreeNodeFlags_OpenOnArrow;
+                if (loadedScene.Active) sceneFlags |= ImGuiTreeNodeFlags_Selected;
+                const std::string label = std::string(loadedScene.Active ? "(A) " : "(S) ") +
+                    (loadedScene.Name.empty() ? loadedScene.SceneGuid.ToString() : loadedScene.Name) +
+                    (loadedScene.Dirty ? " *" : "");
+                const bool open = ImGui::TreeNodeEx(
+                    reinterpret_cast<void*>(static_cast<intptr_t>(MetaCoreAssetGuidHasher{}(loadedScene.SceneGuid))),
+                    sceneFlags,
+                    "%s",
+                    label.c_str()
+                );
+                if (ImGui::IsItemClicked() && !loadedScene.Active)
+                    (void)scenePersistenceService->SetActiveScene(editorContext, loadedScene.SceneGuid);
+                if (ImGui::BeginPopupContextItem()) {
+                    if (ImGui::MenuItem("设为活动场景", nullptr, false, !loadedScene.Active))
+                        (void)scenePersistenceService->SetActiveScene(editorContext, loadedScene.SceneGuid);
+                    if (ImGui::MenuItem("保存全部场景"))
+                        (void)scenePersistenceService->SaveAllScenes(editorContext);
+                    if (ImGui::MenuItem("卸载场景", nullptr, false, openScenes.size() > 1))
+                        (void)scenePersistenceService->UnloadScene(editorContext, loadedScene.SceneGuid, false);
+                    ImGui::EndPopup();
+                }
+                if (open) {
+                    for (MetaCoreId rootId : editorContext.GetScene().GetRootObjectIds()) {
+                        const auto object = editorContext.GetScene().FindGameObject(rootId);
+                        if (!object || !object.HasComponent<MetaCoreSceneObjectIdentityComponent>()) continue;
+                        if (object.GetComponent<MetaCoreSceneObjectIdentityComponent>().SceneGuid == loadedScene.SceneGuid)
+                            DrawHierarchyNode(editorContext, rootId);
+                    }
+                    ImGui::TreePop();
+                }
+            }
+        } else {
+            ImGui::TextColored(ImVec4(0.4F, 0.6F, 1.0F, 1.0F), "(S) Untitled");
+            ImGui::Separator();
+            for (MetaCoreId rootId : editorContext.GetScene().GetRootObjectIds()) DrawHierarchyNode(editorContext, rootId);
         }
 
         DrawRootDropTarget(editorContext);
@@ -9320,7 +9345,10 @@ public:
                     editorContext.ClearSelectedAsset();
                     editorContext.ClearSelectedAssetSubId();
                 } else if (entry.AssetRecord.has_value() && entry.AssetRecord->Type == "scene" && scenePersistenceService) {
-                    (void)scenePersistenceService->LoadScene(editorContext, entry.RelativePath);
+                    if (ImGui::GetIO().KeyCtrl)
+                        (void)scenePersistenceService->LoadSceneAdditive(editorContext, entry.RelativePath);
+                    else
+                        (void)scenePersistenceService->LoadScene(editorContext, entry.RelativePath);
                 } else if (entry.AssetRecord.has_value() && entry.AssetRecord->Type == "model") {
                     (void)MetaCoreInstantiateModelAsset(editorContext, entry.AssetRecord->Guid, std::nullopt);
                 } else if (entry.AssetRecord.has_value() && entry.AssetRecord->Type == "prefab") {
@@ -9381,6 +9409,13 @@ public:
                 if (!entry.IsDirectory && ImGui::MenuItem("打开外部程序")) {
                     MetaCoreOpenPathExternally(project.RootPath / entry.RelativePath);
                 }
+                if (!entry.IsDirectory &&
+                    entry.AssetRecord.has_value() &&
+                    entry.AssetRecord->Type == "scene" &&
+                    scenePersistenceService != nullptr &&
+                    ImGui::MenuItem("Additive 打开场景")) {
+                    (void)scenePersistenceService->LoadSceneAdditive(editorContext, entry.RelativePath);
+                }
                 if (!entry.IsDirectory &&
                     entry.AssetRecord.has_value() &&
                     entry.AssetRecord->Type == "ui_document" &&
diff --git a/Source/MetaCoreEditor/Private/MetaCoreEditorApp.cpp b/Source/MetaCoreEditor/Private/MetaCoreEditorApp.cpp
index 784af8b..f410e71 100644
--- a/Source/MetaCoreEditor/Private/MetaCoreEditorApp.cpp
+++ b/Source/MetaCoreEditor/Private/MetaCoreEditorApp.cpp
@@ -2362,6 +2362,7 @@ bool MetaCoreEditorApp::Initialize(int argc, char* argv[]) {
         LogService_,
         ModuleRegistry_
     );
+    EditorContext_->SetSceneWorld(&SceneWorld_);
 
     MetaCoreTraceStartup("metacore.app: load startup scene");
     bool loadedStartupScene = false;
@@ -2467,6 +2468,18 @@ int MetaCoreEditorApp::Run() {
             playModeService != nullptr && EditorContext_ != nullptr) {
             playModeService->Tick(*EditorContext_, playModeDeltaSeconds);
         }
+        if (EditorContext_ != nullptr) {
+            std::vector<glm::vec3> streamingSources;
+            for (const auto object : Scene_.GetGameObjects()) {
+                if (object.HasComponent<MetaCoreCameraComponent>() &&
+                    object.GetComponent<MetaCoreCameraComponent>().Enabled &&
+                    object.GetComponent<MetaCoreCameraComponent>().IsPrimary) {
+                    streamingSources.push_back(object.GetComponent<MetaCoreTransformComponent>().Position);
+                }
+            }
+            SceneWorld_.UpdateStreaming(streamingSources);
+            SceneWorld_.Tick();
+        }
 
 #if defined(_WIN32)
         ImGui_ImplWin32_NewFrame();
@@ -2821,9 +2834,7 @@ void MetaCoreEditorApp::DrawEditorFrame() {
                     viewportState.Focused &&
                     !ImGui::GetIO().WantCaptureKeyboard &&
                     EditorContext_->GetInput().WasKeyPressed(MetaCoreInputKey::Focus)) {
-                    if (MetaCoreGameObject selectedObject = EditorContext_->GetSelectedGameObject(); selectedObject) {
-                        EditorContext_->GetCameraController().FocusGameObject(selectedObject);
-                    }
+                    SceneInteractionService_.FocusSelectedObject(*EditorContext_);
                 }
 
                 // 4. 同步尺寸给 Filament (SetViewportRect 内部会处理 Resize)
diff --git a/Source/MetaCoreEditor/Private/MetaCoreEditorCameraController.cpp b/Source/MetaCoreEditor/Private/MetaCoreEditorCameraController.cpp
index 8b8bdb6..8599330 100644
--- a/Source/MetaCoreEditor/Private/MetaCoreEditorCameraController.cpp
+++ b/Source/MetaCoreEditor/Private/MetaCoreEditorCameraController.cpp
@@ -31,10 +31,10 @@ void MetaCoreEditorCameraController::Update(
     // Zoom: Alt + Right Drag or Mouse Wheel
     if (viewportState.Hovered && altDown && ImGui::IsMouseDragging(ImGuiMouseButton_Right)) {
         Distance_ *= (1.0F - io.MouseDelta.y * 0.01F);
-        Distance_ = std::clamp(Distance_, 0.5F, 100.0F);
+        Distance_ = std::clamp(Distance_, 0.01F, 10000000.0F);
     } else if (viewportState.Hovered && std::abs(io.MouseWheel) > 0.001F) {
         Distance_ *= (io.MouseWheel > 0.0F) ? 0.88F : 1.12F;
-        Distance_ = std::clamp(Distance_, 0.5F, 100.0F);
+        Distance_ = std::clamp(Distance_, 0.01F, 10000000.0F);
     }
 
     // Orbit: Alt + Left Drag
@@ -97,13 +97,16 @@ void MetaCoreEditorCameraController::Update(
 
 void MetaCoreEditorCameraController::FocusGameObject(const MetaCoreGameObject& gameObject) {
     Target_ = gameObject.GetComponent<MetaCoreTransformComponent>().Position;
-    const float scaleRadius = std::max({gameObject.GetComponent<MetaCoreTransformComponent>().Scale.x, gameObject.GetComponent<MetaCoreTransformComponent>().Scale.y, gameObject.GetComponent<MetaCoreTransformComponent>().Scale.z});
+    const auto& scale = gameObject.GetComponent<MetaCoreTransformComponent>().Scale;
+    const float scaleRadius = std::max({std::abs(scale.x), std::abs(scale.y), std::abs(scale.z), 0.5F});
+    FramingRadius_ = scaleRadius;
     Distance_ = std::max(2.0F, scaleRadius * 4.0F + 1.0F);
 }
 
 void MetaCoreEditorCameraController::FocusBounds(const glm::vec3& center, float radius) {
     Target_ = center;
-    Distance_ = std::max(2.0F, radius * 3.5F + 1.0F);
+    FramingRadius_ = std::max(0.01F, std::isfinite(radius) ? radius : 1.0F);
+    Distance_ = std::max(2.0F, FramingRadius_ * 3.5F + 1.0F);
 }
 
 void MetaCoreEditorCameraController::ApplySceneView(const MetaCoreSceneView& sceneView) {
@@ -111,6 +114,7 @@ void MetaCoreEditorCameraController::ApplySceneView(const MetaCoreSceneView& sce
     FieldOfViewDegrees_ = sceneView.VerticalFieldOfViewDegrees;
     const glm::vec3 offset = sceneView.CameraPosition - sceneView.CameraTarget;
     Distance_ = std::max(0.1F, glm::length(offset));
+    FramingRadius_ = std::max(1.0F, (sceneView.FarClip - Distance_) * 0.25F);
     
     if (Distance_ > 0.001F) {
         const glm::vec3 forward = glm::normalize(sceneView.CameraTarget - sceneView.CameraPosition);
@@ -125,6 +129,12 @@ MetaCoreSceneView MetaCoreEditorCameraController::BuildSceneView() const {
     sceneView.CameraTarget = Target_;
     sceneView.CameraUp = glm::vec3(0.0F, 0.0F, 1.0F); // Z-up!
     sceneView.VerticalFieldOfViewDegrees = FieldOfViewDegrees_;
+    sceneView.NearClip = std::clamp(Distance_ * 0.0001F, 0.01F, 1.0F);
+    sceneView.FarClip = std::clamp(
+        std::max({1000.0F, Distance_ * 2.0F, Distance_ + FramingRadius_ * 4.0F}),
+        sceneView.NearClip + 1.0F,
+        100000000.0F
+    );
     return sceneView;
 }
 
diff --git a/Source/MetaCoreEditor/Private/MetaCoreEditorCameraController.h b/Source/MetaCoreEditor/Private/MetaCoreEditorCameraController.h
index 6da5901..018dc7a 100644
--- a/Source/MetaCoreEditor/Private/MetaCoreEditorCameraController.h
+++ b/Source/MetaCoreEditor/Private/MetaCoreEditorCameraController.h
@@ -31,6 +31,7 @@ private:
     float FieldOfViewDegrees_ = 60.0F;
     float MoveSpeed_ = 6.0F;
     float MoveSpeedBoost_ = 4.0F;
+    float FramingRadius_ = 10.0F;
 };
 
 }  // namespace MetaCore
diff --git a/Source/MetaCoreEditor/Private/MetaCoreSceneInteractionService.cpp b/Source/MetaCoreEditor/Private/MetaCoreSceneInteractionService.cpp
index d2515f7..6e831c6 100644
--- a/Source/MetaCoreEditor/Private/MetaCoreSceneInteractionService.cpp
+++ b/Source/MetaCoreEditor/Private/MetaCoreSceneInteractionService.cpp
@@ -31,6 +31,7 @@
 #include <limits>
 #include <optional>
 #include <unordered_map>
+#include <unordered_set>
 #include <vector>
 
 namespace MetaCore {
@@ -213,6 +214,60 @@ MetaCoreResolvedPickGeometry MetaCoreResolvePickGeometry(
     return MetaCoreResolvedPickGeometry{};
 }
 
+void MetaCoreAccumulateTransformedBounds(
+    const MetaCorePickBounds& localBounds,
+    const glm::mat4& worldMatrix,
+    bool& initialized,
+    glm::vec3& boundsMin,
+    glm::vec3& boundsMax
+) {
+    for (int cornerIndex = 0; cornerIndex < 8; ++cornerIndex) {
+        const glm::vec3 localPoint(
+            (cornerIndex & 1) != 0 ? localBounds.Max.x : localBounds.Min.x,
+            (cornerIndex & 2) != 0 ? localBounds.Max.y : localBounds.Min.y,
+            (cornerIndex & 4) != 0 ? localBounds.Max.z : localBounds.Min.z
+        );
+        const glm::vec3 worldPoint = glm::vec3(worldMatrix * glm::vec4(localPoint, 1.0F));
+        if (!MetaCoreIsFiniteVec3(worldPoint)) continue;
+        if (!initialized) {
+            boundsMin = worldPoint;
+            boundsMax = worldPoint;
+            initialized = true;
+        } else {
+            boundsMin = glm::min(boundsMin, worldPoint);
+            boundsMax = glm::max(boundsMax, worldPoint);
+        }
+    }
+}
+
+bool MetaCoreComputeWorldRenderBounds(
+    const MetaCoreEditorContext& editorContext,
+    const std::unordered_set<MetaCoreId>& objectIds,
+    glm::vec3& boundsMin,
+    glm::vec3& boundsMax
+) {
+    const auto assetEditingService =
+        editorContext.GetModuleRegistry().ResolveService<MetaCoreIAssetEditingService>();
+    std::unordered_map<MetaCoreAssetGuid, std::optional<MetaCoreModelAssetDocument>, MetaCoreAssetGuidHasher>
+        modelAssetCache;
+    bool initialized = false;
+    for (const auto& object : editorContext.GetScene().GetGameObjects()) {
+        if (!objectIds.empty() && !objectIds.contains(object.GetId())) continue;
+        if (!object.HasComponent<MetaCoreMeshRendererComponent>()) continue;
+        const auto& renderer = object.GetComponent<MetaCoreMeshRendererComponent>();
+        if (!renderer.Visible) continue;
+        const auto geometry = MetaCoreResolvePickGeometry(renderer, assetEditingService, modelAssetCache);
+        MetaCoreAccumulateTransformedBounds(
+            geometry.Bounds,
+            MetaCoreBuildWorldTransformMatrix(editorContext.GetScene(), object.GetId()),
+            initialized,
+            boundsMin,
+            boundsMax
+        );
+    }
+    return initialized;
+}
+
 bool MetaCoreIntersectLocalRayWithAabb(
     const glm::vec3& rayOrigin,
     const glm::vec3& rayDirection,
@@ -660,92 +715,37 @@ void MetaCoreSceneInteractionService::FocusSelectedObject(MetaCoreEditorContext&
         return;
     }
 
-    if (selectedObjectIds.size() == 1) {
-        MetaCoreGameObject selectedObject = editorContext.GetSelectedGameObject();
-        if (selectedObject) {
-            editorContext.GetCameraController().FocusGameObject(selectedObject);
-        }
-        return;
+    std::unordered_set<MetaCoreId> focusObjectIds;
+    for (const MetaCoreId selectedObjectId : selectedObjectIds) {
+        const auto subtree = editorContext.GetScene().GetSubtreeObjectIds(selectedObjectId);
+        focusObjectIds.insert(subtree.begin(), subtree.end());
     }
 
-    bool initialized = false;
     glm::vec3 boundsMin(0.0F);
     glm::vec3 boundsMax(0.0F);
-    for (const MetaCoreId selectedObjectId : selectedObjectIds) {
-        const MetaCoreGameObject selectedObject = editorContext.GetScene().FindGameObject(selectedObjectId);
-        if (!selectedObject) {
-            continue;
-        }
-
-        const float extent = std::max({
-            std::abs(selectedObject.GetComponent<MetaCoreTransformComponent>().Scale.x),
-            std::abs(selectedObject.GetComponent<MetaCoreTransformComponent>().Scale.y),
-            std::abs(selectedObject.GetComponent<MetaCoreTransformComponent>().Scale.z),
-            0.5F
-        });
-        const glm::vec3 objectMin = selectedObject.GetComponent<MetaCoreTransformComponent>().Position - glm::vec3(extent);
-        const glm::vec3 objectMax = selectedObject.GetComponent<MetaCoreTransformComponent>().Position + glm::vec3(extent);
-
-        if (!initialized) {
-            boundsMin = objectMin;
-            boundsMax = objectMax;
-            initialized = true;
-            continue;
-        }
-
-        boundsMin = glm::min(boundsMin, objectMin);
-        boundsMax = glm::max(boundsMax, objectMax);
-    }
-
-    if (!initialized) {
+    if (!MetaCoreComputeWorldRenderBounds(editorContext, focusObjectIds, boundsMin, boundsMax)) {
+        const MetaCoreGameObject selectedObject = editorContext.GetSelectedGameObject();
+        if (selectedObject) editorContext.GetCameraController().FocusGameObject(selectedObject);
         return;
     }
 
     const glm::vec3 center = (boundsMin + boundsMax) * 0.5F;
     const glm::vec3 size = boundsMax - boundsMin;
-    const float radius = std::max({size.x, size.y, size.z, 1.0F}) * 0.5F;
+    const float radius = std::max(glm::length(size) * 0.5F, 0.5F);
     editorContext.GetCameraController().FocusBounds(center, radius);
 }
 
 void MetaCoreSceneInteractionService::FocusVisibleScene(MetaCoreEditorContext& editorContext) const {
-    const auto& gameObjects = editorContext.GetScene().GetGameObjects();
-    bool initialized = false;
     glm::vec3 boundsMin(0.0F);
     glm::vec3 boundsMax(0.0F);
-
-    for (const MetaCoreGameObject& gameObject : gameObjects) {
-        if (gameObject.HasComponent<MetaCoreMeshRendererComponent>() && !gameObject.GetComponent<MetaCoreMeshRendererComponent>().Visible) {
-            continue;
-        }
-
-        const float extent = std::max({
-            std::abs(gameObject.GetComponent<MetaCoreTransformComponent>().Scale.x),
-            std::abs(gameObject.GetComponent<MetaCoreTransformComponent>().Scale.y),
-            std::abs(gameObject.GetComponent<MetaCoreTransformComponent>().Scale.z),
-            0.5F
-        });
-        const glm::vec3 objectMin = gameObject.GetComponent<MetaCoreTransformComponent>().Position - glm::vec3(extent);
-        const glm::vec3 objectMax = gameObject.GetComponent<MetaCoreTransformComponent>().Position + glm::vec3(extent);
-
-        if (!initialized) {
-            boundsMin = objectMin;
-            boundsMax = objectMax;
-            initialized = true;
-            continue;
-        }
-
-        boundsMin = glm::min(boundsMin, objectMin);
-        boundsMax = glm::max(boundsMax, objectMax);
-    }
-
-    if (!initialized) {
+    if (!MetaCoreComputeWorldRenderBounds(editorContext, {}, boundsMin, boundsMax)) {
         editorContext.GetCameraController().FocusBounds(glm::vec3(0.0F, 0.5F, 0.0F), 2.0F);
         return;
     }
 
     const glm::vec3 center = (boundsMin + boundsMax) * 0.5F;
     const glm::vec3 size = boundsMax - boundsMin;
-    const float radius = std::max({size.x, size.y, size.z, 1.0F}) * 0.5F;
+    const float radius = std::max(glm::length(size) * 0.5F, 0.5F);
     editorContext.GetCameraController().FocusBounds(center, radius);
 }
 
diff --git a/Source/MetaCoreEditor/Public/MetaCoreEditor/MetaCoreEditorApp.h b/Source/MetaCoreEditor/Public/MetaCoreEditor/MetaCoreEditorApp.h
index e3a686e..45fc3df 100644
--- a/Source/MetaCoreEditor/Public/MetaCoreEditor/MetaCoreEditorApp.h
+++ b/Source/MetaCoreEditor/Public/MetaCoreEditor/MetaCoreEditorApp.h
@@ -9,6 +9,7 @@
 #include "MetaCoreRender/MetaCoreEditorViewportRenderer.h"
 #include "MetaCoreRender/MetaCoreRenderDevice.h"
 #include "MetaCoreScene/MetaCoreScene.h"
+#include "MetaCoreScene/MetaCoreSceneWorld.h"
 
 #include <memory>
 #include <vector>
@@ -38,6 +39,7 @@ private:
     MetaCoreRenderDevice RenderDevice_{};
     MetaCoreEditorViewportRenderer ViewportRenderer_{};
     MetaCoreScene Scene_{};
+    MetaCoreSceneWorld SceneWorld_{Scene_};
     MetaCoreLogService LogService_{};
     MetaCoreEditorModuleRegistry ModuleRegistry_{};
     MetaCoreSceneInteractionService SceneInteractionService_{};
diff --git a/Source/MetaCoreEditor/Public/MetaCoreEditor/MetaCoreEditorContext.h b/Source/MetaCoreEditor/Public/MetaCoreEditor/MetaCoreEditorContext.h
index 8842267..01c7621 100644
--- a/Source/MetaCoreEditor/Public/MetaCoreEditor/MetaCoreEditorContext.h
+++ b/Source/MetaCoreEditor/Public/MetaCoreEditor/MetaCoreEditorContext.h
@@ -28,6 +28,7 @@ class MetaCoreGameObject;
 class MetaCoreEditorModuleRegistry;
 class MetaCoreEditorCameraController;
 class MetaCorePhysicsWorld;
+class MetaCoreSceneWorld;
 
 enum class MetaCoreGizmoOperation {
     None = 0,
@@ -125,6 +126,8 @@ public:
     [[nodiscard]] MetaCoreEditorViewportRenderer& GetViewportRenderer();
     [[nodiscard]] MetaCoreScene& GetScene();
     [[nodiscard]] const MetaCoreScene& GetScene() const;
+    void SetSceneWorld(MetaCoreSceneWorld* sceneWorld) { SceneWorld_ = sceneWorld; }
+    [[nodiscard]] MetaCoreSceneWorld* GetSceneWorld() const { return SceneWorld_; }
     [[nodiscard]] MetaCoreLogService& GetLogService();
     [[nodiscard]] const MetaCoreLogService& GetLogService() const;
     [[nodiscard]] MetaCoreEditorModuleRegistry& GetModuleRegistry();
@@ -219,6 +222,7 @@ private:
     MetaCoreRenderDevice& RenderDevice_;
     MetaCoreEditorViewportRenderer& ViewportRenderer_;
     MetaCoreScene& Scene_;
+    MetaCoreSceneWorld* SceneWorld_ = nullptr;
     MetaCoreLogService& LogService_;
     MetaCoreEditorModuleRegistry& ModuleRegistry_;
     std::unique_ptr<MetaCoreEditorCameraController> CameraController_;
diff --git a/Source/MetaCoreEditor/Public/MetaCoreEditor/MetaCoreEditorServices.h b/Source/MetaCoreEditor/Public/MetaCoreEditor/MetaCoreEditorServices.h
index 36c04ca..c00f163 100644
--- a/Source/MetaCoreEditor/Public/MetaCoreEditor/MetaCoreEditorServices.h
+++ b/Source/MetaCoreEditor/Public/MetaCoreEditor/MetaCoreEditorServices.h
@@ -7,6 +7,7 @@
 #include "MetaCoreFoundation/MetaCorePackage.h"
 #include "MetaCoreFoundation/MetaCoreReflection.h"
 #include "MetaCoreScene/MetaCoreScene.h"
+#include "MetaCoreScene/MetaCoreSceneWorld.h"
 #include "MetaCoreScripting/MetaCoreScripting.h"
 
 #include <cstddef>
@@ -310,8 +311,13 @@ public:
     [[nodiscard]] virtual std::vector<std::filesystem::path> GetKnownScenePaths() const = 0;
     virtual bool LoadStartupScene(MetaCoreEditorContext& editorContext) = 0;
     virtual bool LoadScene(MetaCoreEditorContext& editorContext, const std::filesystem::path& relativeScenePath) = 0;
+    virtual bool LoadSceneAdditive(MetaCoreEditorContext& editorContext, const std::filesystem::path& relativeScenePath) = 0;
+    virtual bool UnloadScene(MetaCoreEditorContext& editorContext, const MetaCoreAssetGuid& sceneGuid, bool force) = 0;
+    virtual bool SetActiveScene(MetaCoreEditorContext& editorContext, const MetaCoreAssetGuid& sceneGuid) = 0;
     virtual bool SaveCurrentScene(MetaCoreEditorContext& editorContext) = 0;
     virtual bool SaveSceneAs(MetaCoreEditorContext& editorContext, const std::filesystem::path& relativeScenePath) = 0;
+    virtual bool SaveAllScenes(MetaCoreEditorContext& editorContext) = 0;
+    [[nodiscard]] virtual std::vector<MetaCoreLoadedSceneInfo> GetOpenScenes(const MetaCoreEditorContext& editorContext) const = 0;
     virtual void UpdateDirtyState(const MetaCoreSceneSnapshot& snapshot) = 0;
 };
 
diff --git a/Source/MetaCoreRender/Private/MetaCoreFilamentSceneBridge.cpp b/Source/MetaCoreRender/Private/MetaCoreFilamentSceneBridge.cpp
index bc368ca..5ea77f2 100644
--- a/Source/MetaCoreRender/Private/MetaCoreFilamentSceneBridge.cpp
+++ b/Source/MetaCoreRender/Private/MetaCoreFilamentSceneBridge.cpp
@@ -183,8 +183,18 @@ void MetaCoreFilamentMaterialDebugLog(const std::string& message) {
     return stream.str();
 }
 
-[[nodiscard]] bool MetaCorePreserveGltfBlendAlphaMode() {
-    const char* preserveBlend = std::getenv("METACORE_GLTF_PRESERVE_BLEND_ALPHA");
+[[nodiscard]] bool MetaCoreForceGltfBlendAsMask() {
+    const char* forceMask = std::getenv("METACORE_GLTF_FORCE_BLEND_AS_MASK");
+    if (forceMask == nullptr) {
+        return false;
+    }
+    return std::strcmp(forceMask, "1") == 0 ||
+           std::strcmp(forceMask, "true") == 0 ||
+           std::strcmp(forceMask, "TRUE") == 0;
+}
+
+[[nodiscard]] bool MetaCorePreserveDoubleSidedGltfBlend() {
+    const char* preserveBlend = std::getenv("METACORE_GLTF_PRESERVE_DOUBLE_SIDED_BLEND");
     if (preserveBlend == nullptr) {
         return false;
     }
@@ -245,17 +255,29 @@ public:
 private:
     void NormalizeAlphaMode(filament::gltfio::MaterialKey* config, const char* label) {
         if (config == nullptr ||
-            MetaCorePreserveGltfBlendAlphaMode() ||
             config->alphaMode != filament::gltfio::AlphaMode::BLEND) {
             return;
         }
 
+        const bool forceAllBlendAsMask = MetaCoreForceGltfBlendAsMask();
+        const bool stabilizeDoubleSidedCutout =
+            config->doubleSided && !MetaCorePreserveDoubleSidedGltfBlend();
+        if (!forceAllBlendAsMask && !stabilizeDoubleSidedCutout) {
+            return;
+        }
+
         config->alphaMode = filament::gltfio::AlphaMode::MASK;
         if (!LoggedBlendAsMask_) {
-            MetaCoreFilamentDebugLog(
-                "GLTF alphaMode=BLEND is rendered as MASK by default for stable foliage depth. "
-                "Set METACORE_GLTF_PRESERVE_BLEND_ALPHA=1 to keep GLTF blend materials."
-            );
+            if (forceAllBlendAsMask) {
+                MetaCoreFilamentDebugLog(
+                    "GLTF alphaMode=BLEND is forced to MASK by METACORE_GLTF_FORCE_BLEND_AS_MASK."
+                );
+            } else {
+                MetaCoreFilamentDebugLog(
+                    "GLTF double-sided BLEND materials use MASK for stable foliage depth. "
+                    "Set METACORE_GLTF_PRESERVE_DOUBLE_SIDED_BLEND=1 for true double-sided transparency."
+                );
+            }
             LoggedBlendAsMask_ = true;
         }
         if (label != nullptr && label[0] != '\0') {
@@ -1620,6 +1642,12 @@ public:
                                CurrentSceneView_.NearClip, CurrentSceneView_.FarClip);
         const glm::mat4 viewProjection = projectionMatrix * viewMatrix;
         const MetaCoreViewFrustum frustum = MetaCoreExtractFrustum(viewProjection);
+        // gltfio already owns exact per-primitive bounds for imported assets.  The ECS
+        // snapshot currently only has a unit transform proxy for these nodes, which is
+        // not a conservative bound for large or offset meshes.  Running that proxy
+        // through the engine BVH / software HZB causes whole model sections to pop as
+        // their node origins cross the view frustum.  Keep hierarchy/layer/distance
+        // visibility here, then leave geometric frustum culling to Filament.
         std::vector<MetaCoreBvhItem> visibilityItems;
         visibilityItems.reserve(resolvedSnapshot.Renderables.size());
         for (const auto& renderable : resolvedSnapshot.Renderables) {
@@ -1628,6 +1656,9 @@ public:
                 MetaCoreAccumulateVisibilityResult(RenderingStatistics_, lodCulled ? MetaCoreVisibilityResult::LodCulled : MetaCoreVisibilityResult::DistanceCulled);
                 continue;
             }
+            if (MetaCoreUsesNativeGltfVisibility(renderable)) {
+                continue;
+            }
             visibilityItems.push_back({renderable.ObjectId, renderable.WorldBounds, renderable.RenderingLayerMask,
                                        renderable.MaxDrawDistance, !renderable.StaticForCulling});
         }
@@ -1652,7 +1683,40 @@ public:
         };
         std::unordered_set<MetaCoreId> currentVisible;
         for (auto& renderable : resolvedSnapshot.Renderables) {
-            if (!renderable.Visible || !bvhVisibleSet.contains(renderable.ObjectId)) { renderable.Visible=false; continue; }
+            if (!renderable.Visible) {
+                continue;
+            }
+            if (MetaCoreUsesNativeGltfVisibility(renderable)) {
+                const bool layerVisible =
+                    (renderable.RenderingLayerMask & CurrentSceneView_.CullingMask) != 0U;
+                const bool distanceVisible =
+                    renderable.MaxDrawDistance <= 0.0F ||
+                    glm::distance(
+                        CurrentSceneView_.CameraPosition,
+                        glm::vec3(renderable.WorldMatrix[3])
+                    ) <= renderable.MaxDrawDistance;
+                renderable.Visible = layerVisible && distanceVisible;
+                if (renderable.Visible) {
+                    currentVisible.insert(renderable.ObjectId);
+                    MetaCoreAccumulateVisibilityResult(
+                        RenderingStatistics_,
+                        MetaCoreVisibilityResult::Visible,
+                        renderable.TriangleCount
+                    );
+                    RenderingStatistics_.EstimatedVideoMemoryBytes +=
+                        renderable.EstimatedVideoMemoryBytes;
+                } else {
+                    MetaCoreAccumulateVisibilityResult(
+                        RenderingStatistics_,
+                        MetaCoreVisibilityResult::DistanceCulled
+                    );
+                }
+                continue;
+            }
+            if (!bvhVisibleSet.contains(renderable.ObjectId)) {
+                renderable.Visible = false;
+                continue;
+            }
             bool queryVisible=true;glm::vec4 screenBounds{};float nearestDepth=0.0F,farthestDepth=0.0F;
             if(RenderSettings_.EnableOcclusion&&projectBounds(renderable.WorldBounds,screenBounds,nearestDepth,farthestDepth))queryVisible=PreviousHzb_.IsVisible(screenBounds,nearestDepth);
             const bool newlyVisible=!LastFrameVisibleObjects_.contains(renderable.ObjectId);
@@ -1663,7 +1727,7 @@ public:
         }
         constexpr std::uint32_t hzbWidth=64U,hzbHeight=36U;
         std::vector<float> softwareDepth(static_cast<std::size_t>(hzbWidth)*hzbHeight,CurrentSceneView_.FarClip);
-        for(const auto& renderable:resolvedSnapshot.Renderables){if(!renderable.Visible||!renderable.StaticForCulling)continue;glm::vec4 bounds{};float nearestDepth=0.0F,farthestDepth=0.0F;if(!projectBounds(renderable.WorldBounds,bounds,nearestDepth,farthestDepth))continue;const std::uint32_t minX=std::min(hzbWidth-1U,static_cast<std::uint32_t>(std::clamp(bounds.x,0.0F,1.0F)*hzbWidth)),maxX=std::min(hzbWidth-1U,static_cast<std::uint32_t>(std::clamp(bounds.z,0.0F,1.0F)*hzbWidth));const std::uint32_t minY=std::min(hzbHeight-1U,static_cast<std::uint32_t>(std::clamp(bounds.y,0.0F,1.0F)*hzbHeight)),maxY=std::min(hzbHeight-1U,static_cast<std::uint32_t>(std::clamp(bounds.w,0.0F,1.0F)*hzbHeight));for(std::uint32_t y=minY;y<=maxY;++y)for(std::uint32_t x=minX;x<=maxX;++x)softwareDepth[static_cast<std::size_t>(y)*hzbWidth+x]=std::min(softwareDepth[static_cast<std::size_t>(y)*hzbWidth+x],farthestDepth);}
+        for(const auto& renderable:resolvedSnapshot.Renderables){if(!renderable.Visible||!renderable.StaticForCulling||MetaCoreUsesNativeGltfVisibility(renderable))continue;glm::vec4 bounds{};float nearestDepth=0.0F,farthestDepth=0.0F;if(!projectBounds(renderable.WorldBounds,bounds,nearestDepth,farthestDepth))continue;const std::uint32_t minX=std::min(hzbWidth-1U,static_cast<std::uint32_t>(std::clamp(bounds.x,0.0F,1.0F)*hzbWidth)),maxX=std::min(hzbWidth-1U,static_cast<std::uint32_t>(std::clamp(bounds.z,0.0F,1.0F)*hzbWidth));const std::uint32_t minY=std::min(hzbHeight-1U,static_cast<std::uint32_t>(std::clamp(bounds.y,0.0F,1.0F)*hzbHeight)),maxY=std::min(hzbHeight-1U,static_cast<std::uint32_t>(std::clamp(bounds.w,0.0F,1.0F)*hzbHeight));for(std::uint32_t y=minY;y<=maxY;++y)for(std::uint32_t x=minX;x<=maxX;++x)softwareDepth[static_cast<std::size_t>(y)*hzbWidth+x]=std::min(softwareDepth[static_cast<std::size_t>(y)*hzbWidth+x],farthestDepth);}
         (void)PreviousHzb_.Build(hzbWidth,hzbHeight,softwareDepth);LastFrameVisibleObjects_=std::move(currentVisible);PreviousVisibilityCameraPosition_=CurrentSceneView_.CameraPosition;PreviousVisibilityCameraDirection_=cameraDirection;HasPreviousVisibilityCamera_=true;
         std::vector<MetaCoreInstanceCandidate> instanceCandidates;
         instanceCandidates.reserve(snapshot.Renderables.size());
diff --git a/Source/MetaCoreRender/Public/MetaCoreRender/MetaCoreSceneRenderSync.h b/Source/MetaCoreRender/Public/MetaCoreRender/MetaCoreSceneRenderSync.h
index 925f6f9..71e047c 100644
--- a/Source/MetaCoreRender/Public/MetaCoreRender/MetaCoreSceneRenderSync.h
+++ b/Source/MetaCoreRender/Public/MetaCoreRender/MetaCoreSceneRenderSync.h
@@ -60,6 +60,14 @@ struct MetaCoreRenderSyncRenderable {
     std::uint64_t EstimatedVideoMemoryBytes = 0U;
 };
 
+[[nodiscard]] inline bool MetaCoreUsesNativeGltfVisibility(
+    const MetaCoreRenderSyncRenderable& renderable
+) {
+    return renderable.MeshSource == MetaCoreMeshSourceKind::Asset &&
+           !renderable.SourceModelPath.empty() &&
+           renderable.HostRootId != 0;
+}
+
 struct MetaCoreRenderSyncCamera {
     MetaCoreId ObjectId = 0;
     bool IsPrimary = false;
diff --git a/Source/MetaCoreScene/Private/MetaCorePrefab.cpp b/Source/MetaCoreScene/Private/MetaCorePrefab.cpp
new file mode 100644
index 0000000..cf15b07
--- /dev/null
+++ b/Source/MetaCoreScene/Private/MetaCorePrefab.cpp
@@ -0,0 +1,388 @@
+#include "MetaCoreScene/MetaCorePrefab.h"
+
+#include "MetaCoreScene/MetaCoreSceneWorld.h"
+
+#include <algorithm>
+#include <nlohmann/json.hpp>
+#include <unordered_set>
+
+namespace MetaCore {
+
+namespace {
+
+using json = nlohmann::json;
+
+glm::vec3 ReadVec3(std::string_view value, bool& valid) {
+    try {
+        const json parsed = json::parse(value);
+        if (!parsed.is_array() || parsed.size() < 3) return {};
+        valid = true;
+        return {parsed[0].get<float>(), parsed[1].get<float>(), parsed[2].get<float>()};
+    } catch (...) {
+        return {};
+    }
+}
+
+template <typename T>
+bool ReadScalar(std::string_view value, T& output) {
+    try {
+        output = json::parse(value).get<T>();
+        return true;
+    } catch (...) {
+        return false;
+    }
+}
+
+MetaCoreGameObjectData* FindNode(MetaCorePrefabDocument& document, const MetaCoreAssetGuid& nodeGuid) {
+    const auto iterator = std::find_if(document.GameObjects.begin(), document.GameObjects.end(), [&](const auto& object) {
+        return object.StableObjectGuid == nodeGuid;
+    });
+    return iterator == document.GameObjects.end() ? nullptr : &*iterator;
+}
+
+const MetaCoreGameObjectData* FindNode(const MetaCorePrefabDocument& document, const MetaCoreAssetGuid& nodeGuid) {
+    const auto iterator = std::find_if(document.GameObjects.begin(), document.GameObjects.end(), [&](const auto& object) {
+        return object.StableObjectGuid == nodeGuid;
+    });
+    return iterator == document.GameObjects.end() ? nullptr : &*iterator;
+}
+
+void NormalizePrefab(MetaCorePrefabDocument& document) {
+    if (!document.PrefabGuid.IsValid()) document.PrefabGuid = MetaCoreAssetGuid::Generate();
+    for (auto& object : document.GameObjects) {
+        if (!object.StableObjectGuid.IsValid())
+            object.StableObjectGuid = MetaCoreBuildDeterministicGuid(document.PrefabGuid, object.Id);
+    }
+    document.SchemaVersion = GMetaCorePrefabSchemaVersion;
+}
+
+void MergeVariantObjects(MetaCorePrefabDocument& target, const MetaCorePrefabDocument& layer) {
+    for (const auto& object : layer.GameObjects) {
+        const auto iterator = std::find_if(target.GameObjects.begin(), target.GameObjects.end(), [&](const auto& current) {
+            return current.StableObjectGuid == object.StableObjectGuid;
+        });
+        if (iterator == target.GameObjects.end()) target.GameObjects.push_back(object);
+        else *iterator = object;
+    }
+}
+
+}  // namespace
+
+MetaCorePrefabOverrideRegistry::MetaCorePrefabOverrideRegistry() {
+    RegisterPropertyHandler("Name", [](MetaCoreGameObjectData& object, std::string_view path, std::string_view value) {
+        return path == "Value" && ReadScalar(value, object.Name);
+    });
+    RegisterPropertyHandler("Transform", [](MetaCoreGameObjectData& object, std::string_view path, std::string_view value) {
+        bool valid = false;
+        const glm::vec3 parsed = ReadVec3(value, valid);
+        if (!valid) return false;
+        if (path == "Position") object.Transform.Position = parsed;
+        else if (path == "RotationEulerDegrees") object.Transform.RotationEulerDegrees = parsed;
+        else if (path == "Scale") object.Transform.Scale = parsed;
+        else return false;
+        return true;
+    });
+    RegisterPropertyHandler("Active", [](MetaCoreGameObjectData& object, std::string_view path, std::string_view value) {
+        if (path != "Active") return false;
+        if (!object.Active) object.Active = MetaCoreActiveComponent{};
+        return ReadScalar(value, object.Active->Active);
+    });
+    RegisterPropertyHandler("Camera", [](MetaCoreGameObjectData& object, std::string_view path, std::string_view value) {
+        if (!object.Camera) object.Camera = MetaCoreCameraComponent{};
+        if (path == "FieldOfViewDegrees") return ReadScalar(value, object.Camera->FieldOfViewDegrees);
+        if (path == "NearClip") return ReadScalar(value, object.Camera->NearClip);
+        if (path == "FarClip") return ReadScalar(value, object.Camera->FarClip);
+        if (path == "Enabled") return ReadScalar(value, object.Camera->Enabled);
+        if (path == "IsPrimary") return ReadScalar(value, object.Camera->IsPrimary);
+        return false;
+    });
+    RegisterPropertyHandler("Light", [](MetaCoreGameObjectData& object, std::string_view path, std::string_view value) {
+        if (!object.Light) object.Light = MetaCoreLightComponent{};
+        if (path == "Intensity") return ReadScalar(value, object.Light->Intensity);
+        if (path == "Enabled") return ReadScalar(value, object.Light->Enabled);
+        if (path == "Color") {
+            bool valid = false;
+            const auto parsed = ReadVec3(value, valid);
+            if (valid) object.Light->Color = parsed;
+            return valid;
+        }
+        return false;
+    });
+}
+
+void MetaCorePrefabOverrideRegistry::RegisterPropertyHandler(std::string componentTypeId, PropertyHandler handler) {
+    PropertyHandlers_[std::move(componentTypeId)] = std::move(handler);
+}
+
+bool MetaCorePrefabOverrideRegistry::Apply(
+    MetaCorePrefabDocument& document,
+    const MetaCorePrefabOverrideDocument& overrideValue
+) const {
+    MetaCoreGameObjectData* object = FindNode(document, overrideValue.TargetNodeGuid);
+    if (!object) return false;
+    switch (overrideValue.Operation) {
+    case MetaCorePrefabOverrideOperation::SetProperty: {
+        const auto handler = PropertyHandlers_.find(overrideValue.ComponentTypeId);
+        return handler != PropertyHandlers_.end() &&
+            handler->second(*object, overrideValue.PropertyPath, overrideValue.ValueJson);
+    }
+    case MetaCorePrefabOverrideOperation::AddComponent:
+        if (overrideValue.ComponentTypeId == "Active") object->Active = MetaCoreActiveComponent{};
+        else if (overrideValue.ComponentTypeId == "Camera") object->Camera = MetaCoreCameraComponent{};
+        else if (overrideValue.ComponentTypeId == "Light") object->Light = MetaCoreLightComponent{};
+        else if (overrideValue.ComponentTypeId == "MeshRenderer") object->MeshRenderer = MetaCoreMeshRendererComponent{};
+        else if (overrideValue.ComponentTypeId == "Collider") object->Collider = MetaCoreColliderComponent{};
+        else if (overrideValue.ComponentTypeId == "RigidBody") object->RigidBody = MetaCoreRigidBodyComponent{};
+        else if (overrideValue.ComponentTypeId == "Rotator") object->Rotator = MetaCoreRotatorComponent{};
+        else if (overrideValue.ComponentTypeId == "Animator") object->Animator = MetaCoreAnimatorComponent{};
+        else if (overrideValue.ComponentTypeId == "TimelineDirector") object->TimelineDirector = MetaCoreTimelineDirectorComponent{};
+        else if (overrideValue.ComponentTypeId == "Script") object->Script = MetaCoreScriptComponent{};
+        else if (overrideValue.ComponentTypeId == "UiRenderer") object->UiRenderer = MetaCoreUiRendererComponent{};
+        else if (overrideValue.ComponentTypeId == "Interactable") object->Interactable = MetaCoreInteractableComponent{};
+        else if (overrideValue.ComponentTypeId == "PhysicsConstraint") object->PhysicsConstraint = MetaCorePhysicsConstraintComponent{};
+        else if (overrideValue.ComponentTypeId == "CharacterController") object->CharacterController = MetaCoreCharacterControllerComponent{};
+        else if (overrideValue.ComponentTypeId == "ReflectionProbe") object->ReflectionProbe = MetaCoreReflectionProbeComponent{};
+        else if (overrideValue.ComponentTypeId == "LodGroup") object->LodGroup = MetaCoreLodGroupComponent{};
+        else if (overrideValue.ComponentTypeId == "ParticleEmitter") object->ParticleEmitter = MetaCoreParticleEmitterComponent{};
+        else if (overrideValue.ComponentTypeId == "LineRenderer") object->LineRenderer = MetaCoreLineRendererComponent{};
+        else if (overrideValue.ComponentTypeId == "TrailRenderer") object->TrailRenderer = MetaCoreTrailRendererComponent{};
+        else if (overrideValue.ComponentTypeId == "DecalProjector") object->DecalProjector = MetaCoreDecalProjectorComponent{};
+        else if (overrideValue.ComponentTypeId == "Terrain") object->Terrain = MetaCoreTerrainComponent{};
+        else return false;
+        return true;
+    case MetaCorePrefabOverrideOperation::RemoveComponent:
+        if (overrideValue.ComponentTypeId == "Active") object->Active.reset();
+        else if (overrideValue.ComponentTypeId == "Camera") object->Camera.reset();
+        else if (overrideValue.ComponentTypeId == "Light") object->Light.reset();
+        else if (overrideValue.ComponentTypeId == "MeshRenderer") object->MeshRenderer.reset();
+        else if (overrideValue.ComponentTypeId == "Collider") object->Collider.reset();
+        else if (overrideValue.ComponentTypeId == "RigidBody") object->RigidBody.reset();
+        else if (overrideValue.ComponentTypeId == "Rotator") object->Rotator.reset();
+        else if (overrideValue.ComponentTypeId == "Animator") object->Animator.reset();
+        else if (overrideValue.ComponentTypeId == "TimelineDirector") object->TimelineDirector.reset();
+        else if (overrideValue.ComponentTypeId == "Script") object->Script.reset();
+        else if (overrideValue.ComponentTypeId == "UiRenderer") object->UiRenderer.reset();
+        else if (overrideValue.ComponentTypeId == "Interactable") object->Interactable.reset();
+        else if (overrideValue.ComponentTypeId == "PhysicsConstraint") object->PhysicsConstraint.reset();
+        else if (overrideValue.ComponentTypeId == "CharacterController") object->CharacterController.reset();
+        else if (overrideValue.ComponentTypeId == "ReflectionProbe") object->ReflectionProbe.reset();
+        else if (overrideValue.ComponentTypeId == "LodGroup") object->LodGroup.reset();
+        else if (overrideValue.ComponentTypeId == "ParticleEmitter") object->ParticleEmitter.reset();
+        else if (overrideValue.ComponentTypeId == "LineRenderer") object->LineRenderer.reset();
+        else if (overrideValue.ComponentTypeId == "TrailRenderer") object->TrailRenderer.reset();
+        else if (overrideValue.ComponentTypeId == "DecalProjector") object->DecalProjector.reset();
+        else if (overrideValue.ComponentTypeId == "Terrain") object->Terrain.reset();
+        else return false;
+        return true;
+    case MetaCorePrefabOverrideOperation::RemoveChild: {
+        std::unordered_set<MetaCoreId> removed{object->Id};
+        bool changed = true;
+        while (changed) {
+            changed = false;
+            for (const auto& candidate : document.GameObjects)
+                if (removed.contains(candidate.ParentId) && removed.insert(candidate.Id).second) changed = true;
+        }
+        std::erase_if(document.GameObjects, [&](const auto& candidate) { return removed.contains(candidate.Id); });
+        return true;
+    }
+    case MetaCorePrefabOverrideOperation::Reparent: {
+        const auto parentGuid = MetaCoreAssetGuid::Parse(overrideValue.ValueJson);
+        if (!parentGuid) return false;
+        const auto* parent = FindNode(document, *parentGuid);
+        if (!parent || parent->Id == object->Id) return false;
+        object->ParentId = parent->Id;
+        return true;
+    }
+    case MetaCorePrefabOverrideOperation::AddChild: {
+        try {
+            const json value = json::parse(overrideValue.ValueJson);
+            MetaCoreGameObjectData child;
+            child.Id = 1;
+            for (const auto& current : document.GameObjects) child.Id = std::max(child.Id, current.Id + 1);
+            child.ParentId = object->Id;
+            child.Name = value.value("Name", std::string("GameObject"));
+            child.StableObjectGuid = MetaCoreAssetGuid::Parse(value.value("StableObjectGuid", std::string{}))
+                .value_or(MetaCoreBuildDeterministicGuid(document.PrefabGuid, child.Id));
+            if (value.contains("Position")) {
+                bool valid = false;
+                child.Transform.Position = ReadVec3(value["Position"].dump(), valid);
+                if (!valid) return false;
+            }
+            if (value.contains("RotationEulerDegrees")) {
+                bool valid = false;
+                child.Transform.RotationEulerDegrees = ReadVec3(value["RotationEulerDegrees"].dump(), valid);
+                if (!valid) return false;
+            }
+            if (value.contains("Scale")) {
+                bool valid = false;
+                child.Transform.Scale = ReadVec3(value["Scale"].dump(), valid);
+                if (!valid) return false;
+            }
+            document.GameObjects.push_back(std::move(child));
+            return true;
+        } catch (...) {
+            return false;
+        }
+    }
+    default:
+        return false;
+    }
+}
+
+MetaCorePrefabResolver::MetaCorePrefabResolver(PrefabLoader loader, MetaCorePrefabOverrideRegistry registry)
+    : Loader_(std::move(loader)), OverrideRegistry_(std::move(registry)) {}
+
+std::optional<MetaCoreResolvedPrefab> MetaCorePrefabResolver::Resolve(
+    const MetaCoreAssetGuid& prefabGuid,
+    std::string* error
+) const {
+    std::vector<MetaCoreAssetGuid> stack;
+    return ResolveInternal(prefabGuid, stack, error);
+}
+
+std::optional<MetaCoreResolvedPrefab> MetaCorePrefabResolver::ResolveInternal(
+    const MetaCoreAssetGuid& prefabGuid,
+    std::vector<MetaCoreAssetGuid>& stack,
+    std::string* error
+) const {
+    if (!prefabGuid.IsValid() || !Loader_) {
+        if (error) *error = "Prefab GUID is invalid or no loader is configured";
+        return std::nullopt;
+    }
+    if (std::find(stack.begin(), stack.end(), prefabGuid) != stack.end()) {
+        if (error) *error = "Prefab base/nesting dependency cycle at " + prefabGuid.ToString();
+        return std::nullopt;
+    }
+    auto layer = Loader_(prefabGuid);
+    if (!layer) {
+        if (error) *error = "Prefab asset is missing: " + prefabGuid.ToString();
+        return std::nullopt;
+    }
+    if (layer->SchemaVersion > GMetaCorePrefabSchemaVersion) {
+        if (error) *error = "Prefab schema is newer than this engine: " + prefabGuid.ToString();
+        return std::nullopt;
+    }
+    if (!layer->PrefabGuid.IsValid()) layer->PrefabGuid = prefabGuid;
+    NormalizePrefab(*layer);
+    stack.push_back(prefabGuid);
+
+    MetaCoreResolvedPrefab result;
+    if (layer->BasePrefabGuid.IsValid()) {
+        auto base = ResolveInternal(layer->BasePrefabGuid, stack, error);
+        if (!base) {
+            stack.pop_back();
+            return std::nullopt;
+        }
+        result = std::move(*base);
+        result.Document.PrefabGuid = layer->PrefabGuid;
+        result.Document.BasePrefabGuid = layer->BasePrefabGuid;
+        result.Document.Name = layer->Name;
+        MergeVariantObjects(result.Document, *layer);
+    } else {
+        result.Document = *layer;
+    }
+    result.DependencyChain.push_back(prefabGuid);
+    for (const auto& value : layer->Overrides)
+        if (!OverrideRegistry_.Apply(result.Document, value)) result.OrphanOverrides.push_back(value);
+
+    for (const auto& nested : layer->NestedPrefabs) {
+        auto nestedResult = ResolveInternal(nested.PrefabAssetGuid, stack, error);
+        if (!nestedResult) {
+            stack.pop_back();
+            return std::nullopt;
+        }
+        for (const auto& value : nested.Overrides)
+            if (!OverrideRegistry_.Apply(nestedResult->Document, value)) result.OrphanOverrides.push_back(value);
+        const auto* mount = FindNode(result.Document, nested.MountNodeGuid);
+        if (!mount) {
+            MetaCorePrefabOverrideDocument orphan;
+            orphan.TargetNodeGuid = nested.MountNodeGuid;
+            orphan.ComponentTypeId = "NestedPrefab";
+            orphan.ValueJson = nested.PrefabAssetGuid.ToString();
+            result.OrphanOverrides.push_back(std::move(orphan));
+            continue;
+        }
+        const MetaCoreAssetGuid instanceGuid = nested.InstanceGuid.IsValid()
+            ? nested.InstanceGuid
+            : MetaCoreBuildDeterministicGuid(layer->PrefabGuid, nested.PrefabAssetGuid);
+        std::unordered_map<MetaCoreId, MetaCoreId> remap;
+        for (const auto& object : nestedResult->Document.GameObjects)
+            remap[object.Id] = MetaCoreIdGenerator::Generate();
+        for (auto object : nestedResult->Document.GameObjects) {
+            const MetaCoreId oldId = object.Id;
+            object.Id = remap.at(oldId);
+            if (object.ParentId == 0) object.ParentId = mount->Id;
+            else if (const auto parent = remap.find(object.ParentId); parent != remap.end()) object.ParentId = parent->second;
+            else {
+                if (error) *error = "Nested prefab contains a missing parent object";
+                stack.pop_back();
+                return std::nullopt;
+            }
+            object.StableObjectGuid = MetaCoreBuildDeterministicGuid(instanceGuid, object.StableObjectGuid);
+            result.Document.GameObjects.push_back(std::move(object));
+        }
+        result.DependencyChain.insert(result.DependencyChain.end(), nestedResult->DependencyChain.begin(), nestedResult->DependencyChain.end());
+        result.OrphanOverrides.insert(result.OrphanOverrides.end(), nestedResult->OrphanOverrides.begin(), nestedResult->OrphanOverrides.end());
+    }
+    stack.pop_back();
+    return result;
+}
+
+std::optional<std::vector<MetaCoreGameObjectData>> MetaCorePrefabResolver::Instantiate(
+    const MetaCoreAssetGuid& prefabGuid,
+    const MetaCoreAssetGuid& instanceGuid,
+    const std::vector<MetaCorePrefabOverrideDocument>& instanceOverrides,
+    std::string* error
+) const {
+    if (!instanceGuid.IsValid()) {
+        if (error) *error = "Prefab instance GUID is invalid";
+        return std::nullopt;
+    }
+    auto resolved = Resolve(prefabGuid, error);
+    if (!resolved) return std::nullopt;
+    for (const auto& value : instanceOverrides)
+        if (!OverrideRegistry_.Apply(resolved->Document, value)) resolved->OrphanOverrides.push_back(value);
+
+    std::unordered_map<MetaCoreId, MetaCoreId> remap;
+    for (const auto& object : resolved->Document.GameObjects) remap[object.Id] = MetaCoreIdGenerator::Generate();
+    for (auto& object : resolved->Document.GameObjects) {
+        const MetaCoreId oldId = object.Id;
+        const MetaCoreAssetGuid nodeGuid = object.StableObjectGuid;
+        object.Id = remap.at(oldId);
+        if (object.ParentId != 0) {
+            const auto parent = remap.find(object.ParentId);
+            if (parent == remap.end()) {
+                if (error) *error = "Prefab contains a missing parent object";
+                return std::nullopt;
+            }
+            object.ParentId = parent->second;
+        }
+        object.StableObjectGuid = MetaCoreBuildDeterministicGuid(instanceGuid, nodeGuid);
+        MetaCorePrefabInstanceMetadata metadata;
+        metadata.PrefabAssetGuid = prefabGuid;
+        metadata.PrefabObjectId = oldId;
+        metadata.InstanceGuid = instanceGuid;
+        metadata.PrefabNodeGuid = nodeGuid;
+        object.PrefabInstance = metadata;
+    }
+    const MetaCoreId rootId = [&] {
+        const auto root = std::find_if(resolved->Document.GameObjects.begin(), resolved->Document.GameObjects.end(),
+            [](const auto& object) { return object.ParentId == 0; });
+        return root == resolved->Document.GameObjects.end() ? MetaCoreId{} : root->Id;
+    }();
+    for (auto& object : resolved->Document.GameObjects)
+        if (object.PrefabInstance) object.PrefabInstance->PrefabInstanceRootId = rootId;
+    return resolved->Document.GameObjects;
+}
+
+std::vector<std::string> MetaCorePrefabResolver::ValidateDependencies(const MetaCoreAssetGuid& prefabGuid) const {
+    std::string error;
+    const auto result = Resolve(prefabGuid, &error);
+    std::vector<std::string> issues;
+    if (!result) issues.push_back(error);
+    else if (!result->OrphanOverrides.empty())
+        issues.push_back("Prefab contains " + std::to_string(result->OrphanOverrides.size()) + " orphan override(s)");
+    return issues;
+}
+
+}  // namespace MetaCore
diff --git a/Source/MetaCoreScene/Private/MetaCoreScene.cpp b/Source/MetaCoreScene/Private/MetaCoreScene.cpp
index ba31857..4d81d04 100644
--- a/Source/MetaCoreScene/Private/MetaCoreScene.cpp
+++ b/Source/MetaCoreScene/Private/MetaCoreScene.cpp
@@ -465,6 +465,11 @@ MetaCoreSceneSnapshot MetaCoreScene::CaptureSnapshot() const {
         MetaCoreGameObjectData data;
         data.Id = obj.GetId();
         data.ParentId = obj.GetParentId();
+        if (obj.HasComponent<MetaCoreSceneObjectIdentityComponent>()) {
+            const auto& identity = obj.GetComponent<MetaCoreSceneObjectIdentityComponent>();
+            data.SceneGuid = identity.SceneGuid;
+            data.StableObjectGuid = identity.StableObjectGuid;
+        }
         data.Name = obj.GetName();
         data.Transform = obj.GetComponent<MetaCoreTransformComponent>();
         
@@ -523,6 +528,11 @@ void MetaCoreScene::RestoreSnapshot(const MetaCoreSceneSnapshot& snapshot) {
         maxId = std::max(maxId, data.Id);
         MetaCoreGameObject obj = CreateGameObjectWithId(data.Id, data.Name, data.ParentId);
         obj.GetComponent<MetaCoreTransformComponent>() = data.Transform;
+        if (data.SceneGuid.IsValid() || data.StableObjectGuid.IsValid()) {
+            obj.AddComponent<MetaCoreSceneObjectIdentityComponent>(
+                MetaCoreSceneObjectIdentityComponent{data.SceneGuid, data.StableObjectGuid}
+            );
+        }
         
         if (data.Camera.has_value())
             obj.AddComponent<MetaCoreCameraComponent>(data.Camera.value());
diff --git a/Source/MetaCoreScene/Private/MetaCoreScenePackage.cpp b/Source/MetaCoreScene/Private/MetaCoreScenePackage.cpp
index d0f0fa3..b584b1a 100644
--- a/Source/MetaCoreScene/Private/MetaCoreScenePackage.cpp
+++ b/Source/MetaCoreScene/Private/MetaCoreScenePackage.cpp
@@ -15,7 +15,8 @@ namespace {
 [[nodiscard]] MetaCorePackageDocument MetaCoreBuildTypedScenePackage(
     const MetaCoreAssetGuid& assetGuid,
     const std::string& objectName,
-    std::vector<std::byte> payload
+    std::vector<std::byte> payload,
+    const MetaCoreSceneDocument& scene
 ) {
     MetaCorePackageDocument document;
     document.Header.PackageType = MetaCorePackageType::Scene;
@@ -29,6 +30,17 @@ namespace {
         0,
         static_cast<std::uint64_t>(payload.size())
     });
+    for (const auto& subScene : scene.SubScenes) {
+        if (subScene.SceneGuid.IsValid())
+            document.Dependencies.push_back({subScene.SceneGuid, "SubScene"});
+    }
+    for (const auto& instance : scene.PrefabInstances) {
+        if (instance.PrefabAssetGuid.IsValid())
+            document.Dependencies.push_back({instance.PrefabAssetGuid, "PrefabInstance"});
+    }
+    document.CustomVersions.push_back({"MetaCore.Scene", scene.SchemaVersion});
+    for (const auto& component : scene.ComponentVersions)
+        document.CustomVersions.push_back({"MetaCore.Component." + component.TypeId, component.Version});
     document.PayloadSections.push_back(std::move(payload));
     return document;
 }
@@ -110,9 +122,10 @@ bool MetaCoreWriteScenePackage(
 
     const std::string objectName = path.stem().string().empty() ? "Scene" : path.stem().string();
     MetaCorePackageDocument package = MetaCoreBuildTypedScenePackage(
-        MetaCoreAssetGuid::Generate(),
+        document.SceneGuid.IsValid() ? document.SceneGuid : MetaCoreAssetGuid::Generate(),
         objectName,
-        *payload
+        *payload,
+        document
     );
     return MetaCoreWritePackageFile(path, std::move(package), registry);
 }
@@ -123,7 +136,9 @@ std::optional<MetaCoreSceneDocument> MetaCoreReadScenePackage(const std::filesys
     if (!package.has_value() || package->Header.PackageType != MetaCorePackageType::Scene) {
         return std::nullopt;
     }
-    return MetaCoreReadTypedPayload<MetaCoreSceneDocument>(*package, registry, "MetaCoreSceneDocument");
+    auto scene = MetaCoreReadTypedPayload<MetaCoreSceneDocument>(*package, registry, "MetaCoreSceneDocument");
+    if (!scene || scene->SchemaVersion > GMetaCoreSceneSchemaVersion) return std::nullopt;
+    return scene;
 }
 
 std::optional<std::filesystem::path> MetaCoreResolveStartupScenePackagePath(const std::filesystem::path& projectFilePath) {
diff --git a/Source/MetaCoreScene/Private/MetaCoreSceneSerializer.cpp b/Source/MetaCoreScene/Private/MetaCoreSceneSerializer.cpp
index 9d27f59..42f3f5c 100644
--- a/Source/MetaCoreScene/Private/MetaCoreSceneSerializer.cpp
+++ b/Source/MetaCoreScene/Private/MetaCoreSceneSerializer.cpp
@@ -1,10 +1,12 @@
 #include "MetaCoreScene/MetaCoreSceneSerializer.h"
 #include "MetaCoreFoundation/MetaCoreReflection.h"
+#include "MetaCoreScene/MetaCoreSceneWorld.h"
 #include <nlohmann/json.hpp>
 #include <fstream>
 #include <iostream>
 #include <sstream>
 #include <span>
+#include <unordered_map>
 
 using json = nlohmann::json;
 
@@ -33,6 +35,23 @@ static MetaCoreAssetGuid StringToGuid(const std::string& str) {
     return str.empty() ? MetaCoreAssetGuid{} : MetaCoreAssetGuid::Parse(str).value_or(MetaCoreAssetGuid{});
 }
 
+static json ObjectReferenceToJson(const MetaCoreObjectReference& reference) {
+    return {
+        {"SceneGuid", GuidToString(reference.SceneGuid)},
+        {"StableObjectGuid", GuidToString(reference.StableObjectGuid)},
+        {"Strength", static_cast<int>(reference.Strength)}
+    };
+}
+
+static MetaCoreObjectReference JsonToObjectReference(const json& value) {
+    MetaCoreObjectReference result;
+    if (!value.is_object()) return result;
+    result.SceneGuid = StringToGuid(value.value("SceneGuid", std::string{}));
+    result.StableObjectGuid = StringToGuid(value.value("StableObjectGuid", std::string{}));
+    result.Strength = static_cast<MetaCoreObjectReferenceStrength>(value.value("Strength", 0));
+    return result;
+}
+
 template <typename T>
 static std::string ReflectedValueToHex(const T& value, const MetaCoreTypeRegistry& registry) {
     const auto bytes = MetaCoreSerializeToBytes(value, registry); if (!bytes) return {};
@@ -89,6 +108,10 @@ static json GameObjectDataToJson(const MetaCoreGameObjectData& obj, const MetaCo
             objJson["Id"] = obj.Id;
         } else if (objField.Name == "ParentId") {
             objJson["ParentId"] = obj.ParentId;
+        } else if (objField.Name == "SceneGuid") {
+            objJson["SceneGuid"] = GuidToString(obj.SceneGuid);
+        } else if (objField.Name == "StableObjectGuid") {
+            objJson["StableObjectGuid"] = GuidToString(obj.StableObjectGuid);
         } else if (objField.Name == "Name") {
             objJson["Name"] = obj.Name;
         } else if (objField.Name == "Transform") {
@@ -205,7 +228,11 @@ static json GameObjectDataToJson(const MetaCoreGameObjectData& obj, const MetaCo
         } else if (objField.Name == "TimelineDirector" && obj.TimelineDirector.has_value()) {
             const auto& director = *obj.TimelineDirector;
             json bindings = json::array();
-            for (const auto& binding : director.Bindings) bindings.push_back({{"Slot", binding.Slot}, {"ObjectId", binding.ObjectId}});
+            for (const auto& binding : director.Bindings) bindings.push_back({
+                {"Slot", binding.Slot},
+                {"ObjectId", binding.ObjectId},
+                {"ObjectReference", ObjectReferenceToJson(binding.ObjectReference)}
+            });
             objJson["TimelineDirector"] = {{"Enabled", director.Enabled}, {"TimelineAssetGuid", GuidToString(director.TimelineAssetGuid)},
                 {"PlayOnStart", director.PlayOnStart}, {"Loop", director.Loop}, {"Speed", director.Speed}, {"Bindings", std::move(bindings)}};
         } else if (objField.Name == "Script" && obj.Script.has_value()) {
@@ -261,7 +288,8 @@ static json GameObjectDataToJson(const MetaCoreGameObjectData& obj, const MetaCo
         } else if (objField.Name == "PhysicsConstraint" && obj.PhysicsConstraint.has_value()) {
             const auto& value = *obj.PhysicsConstraint;
             objJson["PhysicsConstraint"] = {{"Enabled", value.Enabled}, {"Type", static_cast<int>(value.Type)},
-                {"TargetObjectId", value.TargetObjectId}, {"Anchor", Vec3ToJson(value.Anchor)},
+                {"TargetObjectId", value.TargetObjectId}, {"TargetObjectReference", ObjectReferenceToJson(value.TargetObjectReference)},
+                {"Anchor", Vec3ToJson(value.Anchor)},
                 {"TargetAnchor", Vec3ToJson(value.TargetAnchor)}, {"Axis", Vec3ToJson(value.Axis)},
                 {"LinearLowerLimit", Vec3ToJson(value.LinearLowerLimit)}, {"LinearUpperLimit", Vec3ToJson(value.LinearUpperLimit)},
                 {"AngularLowerLimit", Vec3ToJson(value.AngularLowerLimit)}, {"AngularUpperLimit", Vec3ToJson(value.AngularUpperLimit)},
@@ -310,6 +338,8 @@ static json GameObjectDataToJson(const MetaCoreGameObjectData& obj, const MetaCo
                     if (prefabField.Name == "PrefabAssetGuid") prefabJson["PrefabAssetGuid"] = GuidToString(obj.PrefabInstance->PrefabAssetGuid);
                     else if (prefabField.Name == "PrefabObjectId") prefabJson["PrefabObjectId"] = obj.PrefabInstance->PrefabObjectId;
                     else if (prefabField.Name == "PrefabInstanceRootId") prefabJson["PrefabInstanceRootId"] = obj.PrefabInstance->PrefabInstanceRootId;
+                    else if (prefabField.Name == "InstanceGuid") prefabJson["InstanceGuid"] = GuidToString(obj.PrefabInstance->InstanceGuid);
+                    else if (prefabField.Name == "PrefabNodeGuid") prefabJson["PrefabNodeGuid"] = GuidToString(obj.PrefabInstance->PrefabNodeGuid);
                 }
                 objJson["PrefabInstance"] = prefabJson;
             }
@@ -329,6 +359,10 @@ static MetaCoreGameObjectData JsonToGameObjectData(const json& objJson, const Me
             obj.Id = objJson["Id"].get<MetaCoreId>();
         } else if (objField.Name == "ParentId" && objJson.contains("ParentId")) {
             obj.ParentId = objJson["ParentId"].get<MetaCoreId>();
+        } else if (objField.Name == "SceneGuid" && objJson.contains("SceneGuid")) {
+            obj.SceneGuid = StringToGuid(objJson["SceneGuid"].get<std::string>());
+        } else if (objField.Name == "StableObjectGuid" && objJson.contains("StableObjectGuid")) {
+            obj.StableObjectGuid = StringToGuid(objJson["StableObjectGuid"].get<std::string>());
         } else if (objField.Name == "Name" && objJson.contains("Name")) {
             obj.Name = objJson["Name"].get<std::string>();
         } else if (objField.Name == "Transform" && objJson.contains("Transform")) {
@@ -457,7 +491,13 @@ static MetaCoreGameObjectData JsonToGameObjectData(const json& objJson, const Me
             director.PlayOnStart = value.value("PlayOnStart", true);
             director.Loop = value.value("Loop", false);
             director.Speed = value.value("Speed", 1.0F);
-            for (const auto& binding : value.value("Bindings", json::array())) director.Bindings.push_back({binding.value("Slot", ""), binding.value("ObjectId", MetaCoreId{})});
+            for (const auto& binding : value.value("Bindings", json::array())) {
+                MetaCoreTimelineBinding result;
+                result.Slot = binding.value("Slot", "");
+                result.ObjectId = binding.value("ObjectId", MetaCoreId{});
+                if (binding.contains("ObjectReference")) result.ObjectReference = JsonToObjectReference(binding["ObjectReference"]);
+                director.Bindings.push_back(std::move(result));
+            }
             obj.TimelineDirector = std::move(director);
         } else if (objField.Name == "Script" && objJson.contains("Script")) {
             const auto& scriptJson = objJson["Script"];
@@ -537,6 +577,7 @@ static MetaCoreGameObjectData JsonToGameObjectData(const json& objJson, const Me
             MetaCorePhysicsConstraintComponent component;
             component.Enabled = value.value("Enabled", true); component.Type = static_cast<MetaCorePhysicsConstraintType>(value.value("Type", 0));
             component.TargetObjectId = value.value("TargetObjectId", MetaCoreId{0});
+            if (value.contains("TargetObjectReference")) component.TargetObjectReference = JsonToObjectReference(value["TargetObjectReference"]);
             if (value.contains("Anchor")) component.Anchor = JsonToVec3(value["Anchor"]);
             if (value.contains("TargetAnchor")) component.TargetAnchor = JsonToVec3(value["TargetAnchor"]);
             if (value.contains("Axis")) component.Axis = JsonToVec3(value["Axis"]);
@@ -595,6 +636,8 @@ static MetaCoreGameObjectData JsonToGameObjectData(const json& objJson, const Me
                     if (prefabField.Name == "PrefabAssetGuid" && prefabJson.contains("PrefabAssetGuid")) prefab.PrefabAssetGuid = StringToGuid(prefabJson["PrefabAssetGuid"].get<std::string>());
                     else if (prefabField.Name == "PrefabObjectId" && prefabJson.contains("PrefabObjectId")) prefab.PrefabObjectId = prefabJson["PrefabObjectId"].get<MetaCoreId>();
                     else if (prefabField.Name == "PrefabInstanceRootId" && prefabJson.contains("PrefabInstanceRootId")) prefab.PrefabInstanceRootId = prefabJson["PrefabInstanceRootId"].get<MetaCoreId>();
+                    else if (prefabField.Name == "InstanceGuid" && prefabJson.contains("InstanceGuid")) prefab.InstanceGuid = StringToGuid(prefabJson["InstanceGuid"].get<std::string>());
+                    else if (prefabField.Name == "PrefabNodeGuid" && prefabJson.contains("PrefabNodeGuid")) prefab.PrefabNodeGuid = StringToGuid(prefabJson["PrefabNodeGuid"].get<std::string>());
                 }
                 obj.PrefabInstance = prefab;
             }
@@ -603,13 +646,120 @@ static MetaCoreGameObjectData JsonToGameObjectData(const json& objJson, const Me
     return obj;
 }
 
+static json PrefabOverrideToJson(const MetaCorePrefabOverrideDocument& value) {
+    return {
+        {"TargetNodeGuid", GuidToString(value.TargetNodeGuid)},
+        {"ComponentTypeId", value.ComponentTypeId},
+        {"PropertyPath", value.PropertyPath},
+        {"Operation", static_cast<int>(value.Operation)},
+        {"ValueJson", value.ValueJson}
+    };
+}
+
+static MetaCorePrefabOverrideDocument JsonToPrefabOverride(const json& value) {
+    MetaCorePrefabOverrideDocument result;
+    result.TargetNodeGuid = StringToGuid(value.value("TargetNodeGuid", std::string{}));
+    result.ComponentTypeId = value.value("ComponentTypeId", std::string{});
+    result.PropertyPath = value.value("PropertyPath", std::string{});
+    result.Operation = static_cast<MetaCorePrefabOverrideOperation>(value.value("Operation", 0));
+    result.ValueJson = value.value("ValueJson", std::string{});
+    return result;
+}
+
+static json SchemaVersionsToJson(const std::vector<MetaCoreSchemaVersionEntry>& versions) {
+    json result = json::array();
+    for (const auto& version : versions) {
+        result.push_back({{"TypeId", version.TypeId}, {"Version", version.Version}});
+    }
+    return result;
+}
+
+static std::vector<MetaCoreSchemaVersionEntry> JsonToSchemaVersions(const json& values) {
+    std::vector<MetaCoreSchemaVersionEntry> result;
+    if (!values.is_array()) return result;
+    for (const auto& value : values) {
+        result.push_back({value.value("TypeId", std::string{}), value.value("Version", 1U)});
+    }
+    return result;
+}
+
+static MetaCoreAssetGuid BuildLegacyDocumentGuid(std::string_view kind, std::string_view name) {
+    // Legacy documents do not carry an asset GUID. Derive one from persisted
+    // content so repeated migration/save runs are deterministic.
+    std::uint64_t first = 1469598103934665603ULL;
+    std::uint64_t second = 1099511628211ULL;
+    const auto mix = [&](std::string_view value) {
+        for (const unsigned char character : value) {
+            first = (first ^ character) * 1099511628211ULL;
+            second = (second + character + 0x9e3779b97f4a7c15ULL) * 14029467366897019727ULL;
+        }
+    };
+    mix(kind);
+    mix(name);
+    MetaCoreAssetGuid result;
+    for (std::size_t index = 0; index < 8; ++index) {
+        result.Bytes[index] = static_cast<std::uint8_t>(first >> (index * 8U));
+        result.Bytes[index + 8] = static_cast<std::uint8_t>(second >> (index * 8U));
+    }
+    result.Bytes[6] = static_cast<std::uint8_t>((result.Bytes[6] & 0x0FU) | 0x50U);
+    result.Bytes[8] = static_cast<std::uint8_t>((result.Bytes[8] & 0x3FU) | 0x80U);
+    return result;
+}
+
+static void NormalizeSceneDocumentIdentity(MetaCoreSceneDocument& document) {
+    if (!document.SceneGuid.IsValid()) document.SceneGuid = BuildLegacyDocumentGuid("scene:", document.Name);
+    std::unordered_map<MetaCoreId, MetaCoreAssetGuid> stableIds;
+    for (auto& object : document.GameObjects) {
+        object.SceneGuid = document.SceneGuid;
+        if (!object.StableObjectGuid.IsValid())
+            object.StableObjectGuid = MetaCoreBuildDeterministicGuid(document.SceneGuid, object.Id);
+        stableIds[object.Id] = object.StableObjectGuid;
+    }
+    for (auto& object : document.GameObjects) {
+        if (object.PhysicsConstraint) {
+            auto& reference = object.PhysicsConstraint->TargetObjectReference;
+            if (!reference.IsValid()) {
+                if (const auto target = stableIds.find(object.PhysicsConstraint->TargetObjectId); target != stableIds.end()) {
+                    reference.SceneGuid = document.SceneGuid;
+                    reference.StableObjectGuid = target->second;
+                    reference.Strength = MetaCoreObjectReferenceStrength::Hard;
+                }
+            } else if (!reference.SceneGuid.IsValid()) reference.SceneGuid = document.SceneGuid;
+        }
+        if (object.TimelineDirector) {
+            for (auto& binding : object.TimelineDirector->Bindings) {
+                if (!binding.ObjectReference.IsValid()) {
+                    if (const auto target = stableIds.find(binding.ObjectId); target != stableIds.end()) {
+                        binding.ObjectReference.SceneGuid = document.SceneGuid;
+                        binding.ObjectReference.StableObjectGuid = target->second;
+                    }
+                } else if (!binding.ObjectReference.SceneGuid.IsValid()) binding.ObjectReference.SceneGuid = document.SceneGuid;
+            }
+        }
+    }
+    document.SchemaVersion = GMetaCoreSceneSchemaVersion;
+}
+
+static void NormalizePrefabDocumentIdentity(MetaCorePrefabDocument& document) {
+    if (!document.PrefabGuid.IsValid()) document.PrefabGuid = BuildLegacyDocumentGuid("prefab:", document.Name);
+    for (auto& object : document.GameObjects) {
+        if (!object.StableObjectGuid.IsValid())
+            object.StableObjectGuid = MetaCoreBuildDeterministicGuid(document.PrefabGuid, object.Id);
+    }
+    document.SchemaVersion = GMetaCorePrefabSchemaVersion;
+}
+
 bool MetaCoreSceneSerializer::SaveSceneToJson(
     const std::filesystem::path& absolutePath,
     const MetaCoreSceneDocument& sceneDocument,
     const MetaCoreTypeRegistry& registry
 ) {
     try {
+        MetaCoreSceneDocument normalized = sceneDocument;
+        NormalizeSceneDocumentIdentity(normalized);
         json sceneJson;
+        sceneJson["SchemaVersion"] = normalized.SchemaVersion;
+        sceneJson["SceneGuid"] = GuidToString(normalized.SceneGuid);
 
         // 验证 MetaCoreSceneDocument 反射注册
         const MetaCoreStructDescriptor* sceneDesc = registry.FindStruct<MetaCoreSceneDocument>();
@@ -620,26 +770,55 @@ bool MetaCoreSceneSerializer::SaveSceneToJson(
 
         for (const auto& field : sceneDesc->Fields) {
             if (field.Name == "Name") {
-                sceneJson["SceneName"] = sceneDocument.Name;
+                sceneJson["SceneName"] = normalized.Name;
             } else if (field.Name == "Environment") {
-                sceneJson["Environment"] = SceneEnvironmentToJson(sceneDocument.Environment);
+                sceneJson["Environment"] = SceneEnvironmentToJson(normalized.Environment);
             } else if (field.Name == "Selection") {
                 const MetaCoreStructDescriptor* selDesc = registry.FindStruct<MetaCoreEditorSelectionSnapshot>();
                 if (selDesc) {
                     json selJson = json::object();
                     for (const auto& selField : selDesc->Fields) {
-                        if (selField.Name == "SelectedObjectIds") selJson["SelectedObjectIds"] = sceneDocument.Selection.SelectedObjectIds;
-                        else if (selField.Name == "ActiveObjectId") selJson["ActiveObjectId"] = sceneDocument.Selection.ActiveObjectId;
-                        else if (selField.Name == "SelectionAnchorId") selJson["SelectionAnchorId"] = sceneDocument.Selection.SelectionAnchorId;
+                        if (selField.Name == "SelectedObjectIds") selJson["SelectedObjectIds"] = normalized.Selection.SelectedObjectIds;
+                        else if (selField.Name == "ActiveObjectId") selJson["ActiveObjectId"] = normalized.Selection.ActiveObjectId;
+                        else if (selField.Name == "SelectionAnchorId") selJson["SelectionAnchorId"] = normalized.Selection.SelectionAnchorId;
                     }
                     sceneJson["Selection"] = selJson;
                 }
             } else if (field.Name == "GameObjects") {
                 json gameObjectsArray = json::array();
-                for (const auto& obj : sceneDocument.GameObjects) {
+                for (const auto& obj : normalized.GameObjects) {
                     gameObjectsArray.push_back(GameObjectDataToJson(obj, registry));
                 }
                 sceneJson["GameObjects"] = gameObjectsArray;
+            } else if (field.Name == "SubScenes") {
+                sceneJson["SubScenes"] = json::array();
+                for (const auto& subScene : normalized.SubScenes) {
+                    sceneJson["SubScenes"].push_back({
+                        {"SceneGuid", GuidToString(subScene.SceneGuid)},
+                        {"ScenePath", subScene.ScenePath.generic_string()},
+                        {"LoadPolicy", static_cast<int>(subScene.LoadPolicy)},
+                        {"BoundsCenter", Vec3ToJson(subScene.BoundsCenter)},
+                        {"BoundsExtent", Vec3ToJson(subScene.BoundsExtent)},
+                        {"CellCoordinate", Vec3ToJson(subScene.CellCoordinate)},
+                        {"PreloadDistance", subScene.PreloadDistance},
+                        {"UnloadDistance", subScene.UnloadDistance},
+                        {"Priority", subScene.Priority}
+                    });
+                }
+            } else if (field.Name == "PrefabInstances") {
+                sceneJson["PrefabInstances"] = json::array();
+                for (const auto& instance : normalized.PrefabInstances) {
+                    json overrides = json::array();
+                    for (const auto& entry : instance.Overrides) overrides.push_back(PrefabOverrideToJson(entry));
+                    sceneJson["PrefabInstances"].push_back({
+                        {"InstanceGuid", GuidToString(instance.InstanceGuid)},
+                        {"PrefabAssetGuid", GuidToString(instance.PrefabAssetGuid)},
+                        {"ParentObjectGuid", GuidToString(instance.ParentObjectGuid)},
+                        {"Overrides", std::move(overrides)}
+                    });
+                }
+            } else if (field.Name == "ComponentVersions") {
+                sceneJson["ComponentVersions"] = SchemaVersionsToJson(normalized.ComponentVersions);
             }
         }
 
@@ -672,6 +851,10 @@ std::optional<MetaCoreSceneDocument> MetaCoreSceneSerializer::LoadSceneFromJson(
         file >> sceneJson;
 
         MetaCoreSceneDocument sceneDocument;
+        const std::uint32_t sourceVersion = sceneJson.value("SchemaVersion", 1U);
+        if (sourceVersion > GMetaCoreSceneSchemaVersion) return std::nullopt;
+        sceneDocument.SchemaVersion = sourceVersion;
+        if (sceneJson.contains("SceneGuid")) sceneDocument.SceneGuid = StringToGuid(sceneJson["SceneGuid"].get<std::string>());
 
         // 验证 MetaCoreSceneDocument 反射注册
         const MetaCoreStructDescriptor* sceneDesc = registry.FindStruct<MetaCoreSceneDocument>();
@@ -703,9 +886,35 @@ std::optional<MetaCoreSceneDocument> MetaCoreSceneSerializer::LoadSceneFromJson(
                 for (const auto& objJson : sceneJson["GameObjects"]) {
                     sceneDocument.GameObjects.push_back(JsonToGameObjectData(objJson, registry));
                 }
+            } else if (field.Name == "SubScenes" && sceneJson.contains("SubScenes") && sceneJson["SubScenes"].is_array()) {
+                for (const auto& value : sceneJson["SubScenes"]) {
+                    MetaCoreSubSceneDocument subScene;
+                    subScene.SceneGuid = StringToGuid(value.value("SceneGuid", std::string{}));
+                    subScene.ScenePath = value.value("ScenePath", std::string{});
+                    subScene.LoadPolicy = static_cast<MetaCoreSubSceneLoadPolicy>(value.value("LoadPolicy", 0));
+                    if (value.contains("BoundsCenter")) subScene.BoundsCenter = JsonToVec3(value["BoundsCenter"]);
+                    if (value.contains("BoundsExtent")) subScene.BoundsExtent = JsonToVec3(value["BoundsExtent"]);
+                    if (value.contains("CellCoordinate")) subScene.CellCoordinate = JsonToVec3(value["CellCoordinate"]);
+                    subScene.PreloadDistance = value.value("PreloadDistance", 100.0F);
+                    subScene.UnloadDistance = value.value("UnloadDistance", 125.0F);
+                    subScene.Priority = value.value("Priority", 0);
+                    sceneDocument.SubScenes.push_back(std::move(subScene));
+                }
+            } else if (field.Name == "PrefabInstances" && sceneJson.contains("PrefabInstances") && sceneJson["PrefabInstances"].is_array()) {
+                for (const auto& value : sceneJson["PrefabInstances"]) {
+                    MetaCorePrefabInstanceDocument instance;
+                    instance.InstanceGuid = StringToGuid(value.value("InstanceGuid", std::string{}));
+                    instance.PrefabAssetGuid = StringToGuid(value.value("PrefabAssetGuid", std::string{}));
+                    instance.ParentObjectGuid = StringToGuid(value.value("ParentObjectGuid", std::string{}));
+                    if (value.contains("Overrides")) for (const auto& entry : value["Overrides"]) instance.Overrides.push_back(JsonToPrefabOverride(entry));
+                    sceneDocument.PrefabInstances.push_back(std::move(instance));
+                }
+            } else if (field.Name == "ComponentVersions" && sceneJson.contains("ComponentVersions")) {
+                sceneDocument.ComponentVersions = JsonToSchemaVersions(sceneJson["ComponentVersions"]);
             }
         }
 
+        NormalizeSceneDocumentIdentity(sceneDocument);
         return sceneDocument;
     } catch (const std::exception& e) {
         std::cerr << "LoadSceneFromJson: 发生异常 - " << e.what() << std::endl;
@@ -720,13 +929,32 @@ bool MetaCoreSceneSerializer::SavePrefabToJson(
     const MetaCoreTypeRegistry& registry
 ) {
     try {
+        MetaCorePrefabDocument normalized = prefabDocument;
+        NormalizePrefabDocumentIdentity(normalized);
         json prefabJson;
-        prefabJson["PrefabName"] = prefabDocument.Name;
+        prefabJson["SchemaVersion"] = normalized.SchemaVersion;
+        prefabJson["PrefabGuid"] = GuidToString(normalized.PrefabGuid);
+        prefabJson["BasePrefabGuid"] = GuidToString(normalized.BasePrefabGuid);
+        prefabJson["PrefabName"] = normalized.Name;
         json gameObjectsArray = json::array();
-        for (const auto& obj : prefabDocument.GameObjects) {
+        for (const auto& obj : normalized.GameObjects) {
             gameObjectsArray.push_back(GameObjectDataToJson(obj, registry));
         }
         prefabJson["GameObjects"] = gameObjectsArray;
+        prefabJson["Overrides"] = json::array();
+        for (const auto& value : normalized.Overrides) prefabJson["Overrides"].push_back(PrefabOverrideToJson(value));
+        prefabJson["NestedPrefabs"] = json::array();
+        for (const auto& nested : normalized.NestedPrefabs) {
+            json overrides = json::array();
+            for (const auto& value : nested.Overrides) overrides.push_back(PrefabOverrideToJson(value));
+            prefabJson["NestedPrefabs"].push_back({
+                {"MountNodeGuid", GuidToString(nested.MountNodeGuid)},
+                {"PrefabAssetGuid", GuidToString(nested.PrefabAssetGuid)},
+                {"InstanceGuid", GuidToString(nested.InstanceGuid)},
+                {"Overrides", std::move(overrides)}
+            });
+        }
+        prefabJson["ComponentVersions"] = SchemaVersionsToJson(normalized.ComponentVersions);
 
         std::ofstream file(absolutePath);
         if (!file.is_open()) {
@@ -752,6 +980,11 @@ std::optional<MetaCorePrefabDocument> MetaCoreSceneSerializer::LoadPrefabFromJso
         file >> prefabJson;
 
         MetaCorePrefabDocument doc;
+        const std::uint32_t sourceVersion = prefabJson.value("SchemaVersion", 1U);
+        if (sourceVersion > GMetaCorePrefabSchemaVersion) return std::nullopt;
+        doc.SchemaVersion = sourceVersion;
+        doc.PrefabGuid = StringToGuid(prefabJson.value("PrefabGuid", std::string{}));
+        doc.BasePrefabGuid = StringToGuid(prefabJson.value("BasePrefabGuid", std::string{}));
         if (prefabJson.contains("PrefabName")) {
             doc.Name = prefabJson["PrefabName"].get<std::string>();
         }
@@ -760,6 +993,17 @@ std::optional<MetaCorePrefabDocument> MetaCoreSceneSerializer::LoadPrefabFromJso
                 doc.GameObjects.push_back(JsonToGameObjectData(objJson, registry));
             }
         }
+        if (prefabJson.contains("Overrides")) for (const auto& value : prefabJson["Overrides"]) doc.Overrides.push_back(JsonToPrefabOverride(value));
+        if (prefabJson.contains("NestedPrefabs")) for (const auto& value : prefabJson["NestedPrefabs"]) {
+            MetaCoreNestedPrefabDocument nested;
+            nested.MountNodeGuid = StringToGuid(value.value("MountNodeGuid", std::string{}));
+            nested.PrefabAssetGuid = StringToGuid(value.value("PrefabAssetGuid", std::string{}));
+            nested.InstanceGuid = StringToGuid(value.value("InstanceGuid", std::string{}));
+            if (value.contains("Overrides")) for (const auto& entry : value["Overrides"]) nested.Overrides.push_back(JsonToPrefabOverride(entry));
+            doc.NestedPrefabs.push_back(std::move(nested));
+        }
+        if (prefabJson.contains("ComponentVersions")) doc.ComponentVersions = JsonToSchemaVersions(prefabJson["ComponentVersions"]);
+        NormalizePrefabDocumentIdentity(doc);
         return doc;
     } catch (...) {
         return std::nullopt;
diff --git a/Source/MetaCoreScene/Private/MetaCoreSceneWorld.cpp b/Source/MetaCoreScene/Private/MetaCoreSceneWorld.cpp
new file mode 100644
index 0000000..7571c06
--- /dev/null
+++ b/Source/MetaCoreScene/Private/MetaCoreSceneWorld.cpp
@@ -0,0 +1,565 @@
+#include "MetaCoreScene/MetaCoreSceneWorld.h"
+
+#include <algorithm>
+#include <cmath>
+#include <thread>
+
+namespace MetaCore {
+
+namespace {
+
+void HashBytes(std::uint64_t& hash, const std::uint8_t* bytes, std::size_t count) {
+    for (std::size_t index = 0; index < count; ++index) {
+        hash ^= bytes[index];
+        hash *= 1099511628211ULL;
+    }
+}
+
+float DistanceToBounds(const glm::vec3& point, const glm::vec3& center, const glm::vec3& extent) {
+    const glm::vec3 delta = glm::abs(point - center) - glm::max(extent, glm::vec3(0.0F));
+    const glm::vec3 outside = glm::max(delta, glm::vec3(0.0F));
+    return glm::length(outside);
+}
+
+void RemapLegacyObjectReferences(MetaCoreGameObjectData& object, const std::unordered_map<MetaCoreId, MetaCoreId>& ids) {
+    if (const auto parent = ids.find(object.ParentId); parent != ids.end()) object.ParentId = parent->second;
+    else object.ParentId = 0;
+    if (object.PhysicsConstraint) {
+        if (const auto target = ids.find(object.PhysicsConstraint->TargetObjectId); target != ids.end())
+            object.PhysicsConstraint->TargetObjectId = target->second;
+        else object.PhysicsConstraint->TargetObjectId = 0;
+    }
+    if (object.TimelineDirector) {
+        for (auto& binding : object.TimelineDirector->Bindings) {
+            if (const auto target = ids.find(binding.ObjectId); target != ids.end()) binding.ObjectId = target->second;
+            else binding.ObjectId = 0;
+        }
+    }
+}
+
+}  // namespace
+
+struct MetaCoreSceneWorld::PendingLoad {
+    std::uint64_t RequestId = 0;
+    MetaCoreAssetGuid SceneGuid{};
+    MetaCoreSceneLoadMode Mode = MetaCoreSceneLoadMode::Additive;
+    std::int32_t Priority = 0;
+    bool Cancelled = false;
+    std::future<std::optional<MetaCoreSceneDocument>> Future{};
+};
+
+MetaCoreAssetGuid MetaCoreBuildDeterministicGuid(const MetaCoreAssetGuid& namespaceGuid, const MetaCoreAssetGuid& localGuid) {
+    std::uint64_t first = 1469598103934665603ULL;
+    HashBytes(first, namespaceGuid.Bytes.data(), namespaceGuid.Bytes.size());
+    HashBytes(first, localGuid.Bytes.data(), localGuid.Bytes.size());
+    std::uint64_t second = 1099511628211ULL ^ first;
+    HashBytes(second, localGuid.Bytes.data(), localGuid.Bytes.size());
+    HashBytes(second, namespaceGuid.Bytes.data(), namespaceGuid.Bytes.size());
+    MetaCoreAssetGuid result;
+    for (std::size_t index = 0; index < 8; ++index) {
+        result.Bytes[index] = static_cast<std::uint8_t>((first >> (index * 8U)) & 0xFFU);
+        result.Bytes[index + 8] = static_cast<std::uint8_t>((second >> (index * 8U)) & 0xFFU);
+    }
+    result.Bytes[6] = static_cast<std::uint8_t>((result.Bytes[6] & 0x0FU) | 0x50U);
+    result.Bytes[8] = static_cast<std::uint8_t>((result.Bytes[8] & 0x3FU) | 0x80U);
+    return result;
+}
+
+MetaCoreAssetGuid MetaCoreBuildDeterministicGuid(const MetaCoreAssetGuid& namespaceGuid, std::uint64_t localValue) {
+    MetaCoreAssetGuid local;
+    for (std::size_t index = 0; index < 8; ++index)
+        local.Bytes[index] = static_cast<std::uint8_t>((localValue >> (index * 8U)) & 0xFFU);
+    return MetaCoreBuildDeterministicGuid(namespaceGuid, local);
+}
+
+std::size_t MetaCoreSceneWorld::ObjectKeyHasher::operator()(const ObjectKey& value) const noexcept {
+    MetaCoreAssetGuidHasher hasher;
+    return hasher(value.SceneGuid) ^ (hasher(value.ObjectGuid) + 0x9e3779b97f4a7c15ULL);
+}
+
+MetaCoreSceneWorld::MetaCoreSceneWorld(SceneLoader loader, MetaCoreSceneWorldSettings settings)
+    : Loader_(std::move(loader)), Settings_(settings), OwnedScene_(std::make_unique<MetaCoreScene>()), Scene_(OwnedScene_.get()) {}
+
+MetaCoreSceneWorld::MetaCoreSceneWorld(MetaCoreScene& scene, SceneLoader loader, MetaCoreSceneWorldSettings settings)
+    : Loader_(std::move(loader)), Settings_(settings), Scene_(&scene) {}
+
+MetaCoreSceneWorld::~MetaCoreSceneWorld() = default;
+
+void MetaCoreSceneWorld::SetSceneLoader(SceneLoader loader) { Loader_ = std::move(loader); }
+
+std::uint64_t MetaCoreSceneWorld::RequestLoad(
+    const MetaCoreAssetGuid& sceneGuid,
+    MetaCoreSceneLoadMode mode,
+    std::int32_t priority
+) {
+    for (const auto& pending : PendingLoads_) {
+        if (!pending->Cancelled && pending->SceneGuid == sceneGuid) return pending->RequestId;
+    }
+    const std::uint64_t requestId = NextRequestId_++;
+    MetaCoreSceneLoadStatus status{requestId, sceneGuid, MetaCoreSceneLoadState::Loading, {}};
+    if (!sceneGuid.IsValid() || !Loader_) {
+        status.State = MetaCoreSceneLoadState::Failed;
+        status.Error = !sceneGuid.IsValid() ? "Scene GUID is invalid" : "Scene loader is not configured";
+        LoadStatuses_[requestId] = std::move(status);
+        return requestId;
+    }
+    if (IsSceneLoaded(sceneGuid)) {
+        status.State = MetaCoreSceneLoadState::Loaded;
+        LoadStatuses_[requestId] = std::move(status);
+        return requestId;
+    }
+    auto pending = std::make_unique<PendingLoad>();
+    pending->RequestId = requestId;
+    pending->SceneGuid = sceneGuid;
+    pending->Mode = mode;
+    pending->Priority = priority;
+    SceneLoader loader = Loader_;
+    pending->Future = std::async(std::launch::async, [loader = std::move(loader), sceneGuid] {
+        return loader(sceneGuid);
+    });
+    PendingLoads_.push_back(std::move(pending));
+    LoadStatuses_[requestId] = std::move(status);
+    return requestId;
+}
+
+bool MetaCoreSceneWorld::CancelLoad(std::uint64_t requestId) {
+    const auto iterator = std::find_if(PendingLoads_.begin(), PendingLoads_.end(), [&](const auto& pending) {
+        return pending->RequestId == requestId;
+    });
+    if (iterator == PendingLoads_.end()) return false;
+    (*iterator)->Cancelled = true;
+    auto& status = LoadStatuses_[requestId];
+    status.State = MetaCoreSceneLoadState::Cancelled;
+    status.Error = "Load request cancelled";
+    return true;
+}
+
+void MetaCoreSceneWorld::Tick() {
+    std::stable_sort(PendingLoads_.begin(), PendingLoads_.end(), [](const auto& lhs, const auto& rhs) {
+        return lhs->Priority > rhs->Priority;
+    });
+    for (auto iterator = PendingLoads_.begin(); iterator != PendingLoads_.end();) {
+        auto& pending = **iterator;
+        if (pending.Future.wait_for(std::chrono::milliseconds(0)) != std::future_status::ready) {
+            ++iterator;
+            continue;
+        }
+        std::optional<MetaCoreSceneDocument> document = pending.Future.get();
+        auto& status = LoadStatuses_[pending.RequestId];
+        if (pending.Cancelled) {
+            status.State = MetaCoreSceneLoadState::Cancelled;
+        } else if (!document) {
+            status.State = MetaCoreSceneLoadState::Failed;
+            status.Error = "Scene loader returned no document";
+        } else {
+            if (!document->SceneGuid.IsValid()) document->SceneGuid = pending.SceneGuid;
+            std::string error;
+            if (CommitDocument(std::move(*document), pending.Mode, &error)) status.State = MetaCoreSceneLoadState::Loaded;
+            else {
+                status.State = MetaCoreSceneLoadState::Failed;
+                status.Error = std::move(error);
+            }
+        }
+        iterator = PendingLoads_.erase(iterator);
+    }
+}
+
+bool MetaCoreSceneWorld::LoadDocumentNow(MetaCoreSceneDocument document, MetaCoreSceneLoadMode mode, std::string* error) {
+    return CommitDocument(std::move(document), mode, error);
+}
+
+bool MetaCoreSceneWorld::CommitDocument(MetaCoreSceneDocument document, MetaCoreSceneLoadMode mode, std::string* error) {
+    if (document.SchemaVersion > GMetaCoreSceneSchemaVersion) {
+        if (error) *error = "Scene schema is newer than this engine";
+        return false;
+    }
+    if (!document.SceneGuid.IsValid()) {
+        if (error) *error = "Scene document has no stable GUID";
+        return false;
+    }
+    if (IsSceneLoaded(document.SceneGuid)) {
+        if (error) *error = "Scene is already loaded";
+        return false;
+    }
+    if (mode == MetaCoreSceneLoadMode::Replace) {
+        std::vector<MetaCoreAssetGuid> loaded;
+        loaded.reserve(LoadedScenes_.size());
+        for (const auto& [guid, scene] : LoadedScenes_) {
+            (void)scene;
+            loaded.push_back(guid);
+        }
+        for (const auto& guid : loaded) (void)UnloadScene(guid, true);
+        if (LoadedScenes_.empty() && !Scene_->GetGameObjects().empty()) {
+            Scene_->RestoreSnapshot(MetaCoreSceneSnapshot{});
+        }
+    }
+
+    std::unordered_map<MetaCoreId, MetaCoreId> ids;
+    for (const auto& object : document.GameObjects) ids.emplace(object.Id, MetaCoreIdGenerator::Generate());
+
+    LoadedScene record;
+    record.Source = document;
+    record.Source.SchemaVersion = GMetaCoreSceneSchemaVersion;
+    record.LoadMode = mode;
+    MetaCoreSceneSnapshot combined = Scene_->CaptureSnapshot();
+    if (LoadedScenes_.empty()) combined.Environment = document.Environment;
+    for (auto object : document.GameObjects) {
+        const MetaCoreId serializedId = object.Id;
+        object.Id = ids.at(serializedId);
+        object.SceneGuid = document.SceneGuid;
+        if (!object.StableObjectGuid.IsValid())
+            object.StableObjectGuid = MetaCoreBuildDeterministicGuid(document.SceneGuid, serializedId);
+        RemapLegacyObjectReferences(object, ids);
+        record.RuntimeObjectIds.push_back(object.Id);
+        record.RuntimeToSerializedId.emplace(object.Id, serializedId);
+        combined.GameObjects.push_back(std::move(object));
+    }
+    Scene_->RestoreSnapshot(combined);
+    const MetaCoreAssetGuid sceneGuid = document.SceneGuid;
+    LoadedScenes_.emplace(sceneGuid, std::move(record));
+    if (!ActiveSceneGuid_.IsValid() || mode == MetaCoreSceneLoadMode::Replace) ActiveSceneGuid_ = sceneGuid;
+    RebuildObjectIndex();
+    for (auto object : Scene_->GetGameObjects()) {
+        if (object.HasComponent<MetaCorePhysicsConstraintComponent>()) {
+            auto& constraint = object.GetComponent<MetaCorePhysicsConstraintComponent>();
+            if (constraint.TargetObjectReference.IsValid()) {
+                const auto target = ResolveObject(constraint.TargetObjectReference);
+                constraint.TargetObjectId = target ? target.GetId() : 0;
+            }
+        }
+        if (object.HasComponent<MetaCoreTimelineDirectorComponent>()) {
+            for (auto& binding : object.GetComponent<MetaCoreTimelineDirectorComponent>().Bindings) {
+                if (binding.ObjectReference.IsValid()) {
+                    const auto target = ResolveObject(binding.ObjectReference);
+                    binding.ObjectId = target ? target.GetId() : 0;
+                }
+            }
+        }
+    }
+    RebuildHardResidency();
+    Publish({MetaCoreSceneLifecycleEventType::AfterLoad, sceneGuid, LoadedScenes_.at(sceneGuid).RuntimeObjectIds});
+
+    for (const auto& subScene : document.SubScenes) {
+        if (subScene.LoadPolicy == MetaCoreSubSceneLoadPolicy::AlwaysLoaded && !IsSceneLoaded(subScene.SceneGuid))
+            (void)RequestLoad(subScene.SceneGuid, MetaCoreSceneLoadMode::SubScene, subScene.Priority);
+    }
+    return true;
+}
+
+bool MetaCoreSceneWorld::UnloadScene(const MetaCoreAssetGuid& sceneGuid, bool force) {
+    auto iterator = LoadedScenes_.find(sceneGuid);
+    if (iterator == LoadedScenes_.end()) return false;
+    if (!force && HardResidentScenes_.contains(sceneGuid)) return false;
+    const auto objectIds = iterator->second.RuntimeObjectIds;
+    Publish({MetaCoreSceneLifecycleEventType::BeforeUnload, sceneGuid, objectIds});
+    (void)Scene_->DeleteGameObjects(objectIds);
+    LoadedScenes_.erase(iterator);
+    HardResidentScenes_.erase(sceneGuid);
+    if (ActiveSceneGuid_ == sceneGuid)
+        ActiveSceneGuid_ = LoadedScenes_.empty() ? MetaCoreAssetGuid{} : LoadedScenes_.begin()->first;
+    RebuildObjectIndex();
+    RebuildHardResidency();
+    Publish({MetaCoreSceneLifecycleEventType::AfterUnload, sceneGuid, objectIds});
+    return true;
+}
+
+bool MetaCoreSceneWorld::SetActiveScene(const MetaCoreAssetGuid& sceneGuid) {
+    if (!IsSceneLoaded(sceneGuid)) return false;
+    ActiveSceneGuid_ = sceneGuid;
+    return true;
+}
+
+bool MetaCoreSceneWorld::IsSceneLoaded(const MetaCoreAssetGuid& sceneGuid) const {
+    return LoadedScenes_.contains(sceneGuid);
+}
+
+std::vector<MetaCoreLoadedSceneInfo> MetaCoreSceneWorld::GetLoadedScenes() const {
+    std::vector<MetaCoreLoadedSceneInfo> result;
+    result.reserve(LoadedScenes_.size());
+    for (const auto& [guid, scene] : LoadedScenes_) {
+        result.push_back({guid, scene.Source.Name, scene.LoadMode, guid == ActiveSceneGuid_, scene.Dirty,
+            HardResidentScenes_.contains(guid), scene.RuntimeObjectIds});
+    }
+    std::sort(result.begin(), result.end(), [](const auto& lhs, const auto& rhs) {
+        if (lhs.Active != rhs.Active) return lhs.Active;
+        return lhs.Name < rhs.Name;
+    });
+    return result;
+}
+
+std::optional<MetaCoreSceneLoadStatus> MetaCoreSceneWorld::GetLoadStatus(std::uint64_t requestId) const {
+    const auto iterator = LoadStatuses_.find(requestId);
+    return iterator == LoadStatuses_.end() ? std::nullopt : std::optional(iterator->second);
+}
+
+MetaCoreGameObject MetaCoreSceneWorld::ResolveObject(const MetaCoreObjectReference& reference) {
+    if (!reference.IsValid()) return {};
+    MetaCoreAssetGuid sceneGuid = reference.SceneGuid.IsValid() ? reference.SceneGuid : ActiveSceneGuid_;
+    const auto iterator = ObjectIndex_.find({sceneGuid, reference.StableObjectGuid});
+    if (iterator != ObjectIndex_.end()) return Scene_->FindGameObject(iterator->second);
+    if (reference.Strength == MetaCoreObjectReferenceStrength::Hard && sceneGuid.IsValid()) {
+        HardResidentScenes_.insert(sceneGuid);
+        if (!IsSceneLoaded(sceneGuid)) (void)RequestLoad(sceneGuid, MetaCoreSceneLoadMode::SubScene);
+    }
+    return {};
+}
+
+MetaCoreGameObject MetaCoreSceneWorld::ResolveObject(const MetaCoreObjectReference& reference) const {
+    if (!reference.IsValid()) return {};
+    const MetaCoreAssetGuid sceneGuid = reference.SceneGuid.IsValid() ? reference.SceneGuid : ActiveSceneGuid_;
+    const auto iterator = ObjectIndex_.find({sceneGuid, reference.StableObjectGuid});
+    return iterator == ObjectIndex_.end() ? MetaCoreGameObject{} : Scene_->FindGameObject(iterator->second);
+}
+
+MetaCoreObjectReference MetaCoreSceneWorld::BuildObjectReference(
+    MetaCoreId runtimeObjectId,
+    MetaCoreObjectReferenceStrength strength
+) const {
+    const MetaCoreGameObject object = Scene_->FindGameObject(runtimeObjectId);
+    if (!object || !object.HasComponent<MetaCoreSceneObjectIdentityComponent>()) return {};
+    const auto& identity = object.GetComponent<MetaCoreSceneObjectIdentityComponent>();
+    return {identity.SceneGuid, identity.StableObjectGuid, strength};
+}
+
+bool MetaCoreSceneWorld::MoveSubtreeToScene(MetaCoreId rootObjectId, const MetaCoreAssetGuid& targetSceneGuid) {
+    if (!IsSceneLoaded(targetSceneGuid)) return false;
+    const auto ids = Scene_->GetSubtreeObjectIds(rootObjectId);
+    if (ids.empty()) return false;
+    MetaCoreAssetGuid sourceSceneGuid{};
+    for (MetaCoreId id : ids) {
+        auto object = Scene_->FindGameObject(id);
+        if (!object) return false;
+        if (!object.HasComponent<MetaCoreSceneObjectIdentityComponent>())
+            object.AddComponent<MetaCoreSceneObjectIdentityComponent>();
+        if (!sourceSceneGuid.IsValid())
+            sourceSceneGuid = object.GetComponent<MetaCoreSceneObjectIdentityComponent>().SceneGuid;
+        object.GetComponent<MetaCoreSceneObjectIdentityComponent>().SceneGuid = targetSceneGuid;
+    }
+    for (auto& [guid, scene] : LoadedScenes_) {
+        for (MetaCoreId id : ids) std::erase(scene.RuntimeObjectIds, id);
+        if (guid == sourceSceneGuid || guid == targetSceneGuid) scene.Dirty = true;
+    }
+    auto& target = LoadedScenes_.at(targetSceneGuid);
+    target.RuntimeObjectIds.insert(target.RuntimeObjectIds.end(), ids.begin(), ids.end());
+    RebuildObjectIndex();
+    Scene_->IncrementRevision();
+    return true;
+}
+
+std::optional<MetaCoreSceneDocument> MetaCoreSceneWorld::CaptureSceneDocument(const MetaCoreAssetGuid& sceneGuid) const {
+    const auto loaded = LoadedScenes_.find(sceneGuid);
+    if (loaded == LoadedScenes_.end()) return std::nullopt;
+    MetaCoreSceneDocument result = loaded->second.Source;
+    result.SchemaVersion = GMetaCoreSceneSchemaVersion;
+    result.SceneGuid = sceneGuid;
+    result.GameObjects.clear();
+    result.PrefabInstances.clear();
+    const auto snapshot = Scene_->CaptureSnapshot();
+    std::unordered_map<MetaCoreId, MetaCoreId> runtimeToSerialized = loaded->second.RuntimeToSerializedId;
+    std::unordered_set<MetaCoreId> usedSerializedIds;
+    for (const auto& [runtimeId, serializedId] : runtimeToSerialized) {
+        (void)runtimeId;
+        usedSerializedIds.insert(serializedId);
+    }
+    MetaCoreId nextSerializedId = 1;
+    for (const auto& object : snapshot.GameObjects) {
+        if (object.SceneGuid != sceneGuid || runtimeToSerialized.contains(object.Id)) continue;
+        while (usedSerializedIds.contains(nextSerializedId)) ++nextSerializedId;
+        runtimeToSerialized.emplace(object.Id, nextSerializedId);
+        usedSerializedIds.insert(nextSerializedId++);
+    }
+    for (auto object : snapshot.GameObjects) {
+        if (object.SceneGuid != sceneGuid) continue;
+        if (object.PrefabInstance &&
+            object.PrefabInstance->PrefabInstanceRootId == object.Id &&
+            object.PrefabInstance->InstanceGuid.IsValid()) {
+            MetaCorePrefabInstanceDocument instance;
+            instance.InstanceGuid = object.PrefabInstance->InstanceGuid;
+            instance.PrefabAssetGuid = object.PrefabInstance->PrefabAssetGuid;
+            if (object.ParentId != 0) {
+                const auto parent = std::find_if(snapshot.GameObjects.begin(), snapshot.GameObjects.end(),
+                    [&](const auto& candidate) { return candidate.Id == object.ParentId; });
+                if (parent != snapshot.GameObjects.end()) instance.ParentObjectGuid = parent->StableObjectGuid;
+            }
+            result.PrefabInstances.push_back(std::move(instance));
+        }
+        object.Id = runtimeToSerialized.at(object.Id);
+        if (object.ParentId != 0) {
+            const auto parent = runtimeToSerialized.find(object.ParentId);
+            object.ParentId = parent == runtimeToSerialized.end() ? 0 : parent->second;
+        }
+        result.GameObjects.push_back(std::move(object));
+    }
+    return result;
+}
+
+MetaCoreSceneWorldSnapshot MetaCoreSceneWorld::CaptureWorldSnapshot() const {
+    MetaCoreSceneWorldSnapshot snapshot;
+    snapshot.CompositeScene = Scene_->CaptureSnapshot();
+    snapshot.ActiveSceneGuid = ActiveSceneGuid_;
+    snapshot.Scenes.reserve(LoadedScenes_.size());
+    for (const auto& [sceneGuid, loaded] : LoadedScenes_) {
+        if (auto document = CaptureSceneDocument(sceneGuid))
+            snapshot.Scenes.push_back({std::move(*document), loaded.LoadMode, loaded.Dirty});
+    }
+    return snapshot;
+}
+
+void MetaCoreSceneWorld::RestoreWorldSnapshot(const MetaCoreSceneWorldSnapshot& snapshot) {
+    for (auto& pending : PendingLoads_) {
+        pending->Cancelled = true;
+        auto& status = LoadStatuses_[pending->RequestId];
+        status.State = MetaCoreSceneLoadState::Cancelled;
+        status.Error = "Load request cancelled by world restore";
+    }
+    Scene_->RestoreSnapshot(snapshot.CompositeScene);
+    LoadedScenes_.clear();
+    for (const auto& entry : snapshot.Scenes) {
+        LoadedScene loaded;
+        loaded.Source = entry.Document;
+        loaded.LoadMode = entry.LoadMode;
+        loaded.Dirty = entry.Dirty;
+        std::unordered_map<MetaCoreAssetGuid, MetaCoreId, MetaCoreAssetGuidHasher> serializedIds;
+        for (const auto& object : entry.Document.GameObjects)
+            serializedIds[object.StableObjectGuid] = object.Id;
+        for (const auto object : Scene_->GetGameObjects()) {
+            if (!object.HasComponent<MetaCoreSceneObjectIdentityComponent>()) continue;
+            const auto& identity = object.GetComponent<MetaCoreSceneObjectIdentityComponent>();
+            if (identity.SceneGuid != entry.Document.SceneGuid) continue;
+            loaded.RuntimeObjectIds.push_back(object.GetId());
+            if (const auto serialized = serializedIds.find(identity.StableObjectGuid); serialized != serializedIds.end())
+                loaded.RuntimeToSerializedId.emplace(object.GetId(), serialized->second);
+        }
+        LoadedScenes_.emplace(entry.Document.SceneGuid, std::move(loaded));
+    }
+    ActiveSceneGuid_ = LoadedScenes_.contains(snapshot.ActiveSceneGuid)
+        ? snapshot.ActiveSceneGuid
+        : (LoadedScenes_.empty() ? MetaCoreAssetGuid{} : LoadedScenes_.begin()->first);
+    RebuildObjectIndex();
+    RebuildHardResidency();
+}
+
+std::vector<std::string> MetaCoreSceneWorld::ValidateDependencies(const MetaCoreSceneDocument& root) const {
+    std::vector<std::string> issues;
+    std::unordered_set<MetaCoreAssetGuid, MetaCoreAssetGuidHasher> visited;
+    std::unordered_set<MetaCoreAssetGuid, MetaCoreAssetGuidHasher> active;
+    std::function<void(const MetaCoreSceneDocument&)> visit = [&](const MetaCoreSceneDocument& document) {
+        if (active.contains(document.SceneGuid)) {
+            issues.push_back("Scene dependency cycle at " + document.SceneGuid.ToString());
+            return;
+        }
+        if (!visited.insert(document.SceneGuid).second) return;
+        active.insert(document.SceneGuid);
+        std::unordered_set<MetaCoreAssetGuid, MetaCoreAssetGuidHasher> localDependencies;
+        std::vector<MetaCoreAssetGuid> dependencies;
+        for (const auto& subScene : document.SubScenes) {
+            if (!subScene.SceneGuid.IsValid()) {
+                issues.push_back("SubScene has no GUID: " + subScene.ScenePath.generic_string());
+                continue;
+            }
+            if (!localDependencies.insert(subScene.SceneGuid).second)
+                issues.push_back("Duplicate SubScene dependency: " + subScene.SceneGuid.ToString());
+            dependencies.push_back(subScene.SceneGuid);
+            if (subScene.LoadPolicy == MetaCoreSubSceneLoadPolicy::Distance &&
+                (subScene.PreloadDistance < 0.0F || subScene.UnloadDistance < subScene.PreloadDistance))
+                issues.push_back("Distance SubScene has invalid preload/unload thresholds: " + subScene.SceneGuid.ToString());
+        }
+        for (const auto& object : document.GameObjects) {
+            if (object.PhysicsConstraint) {
+                const auto& reference = object.PhysicsConstraint->TargetObjectReference;
+                if (reference.IsValid() && reference.Strength == MetaCoreObjectReferenceStrength::Hard)
+                    dependencies.push_back(reference.SceneGuid);
+            }
+            if (object.TimelineDirector) for (const auto& binding : object.TimelineDirector->Bindings) {
+                if (binding.ObjectReference.IsValid() &&
+                    binding.ObjectReference.Strength == MetaCoreObjectReferenceStrength::Hard)
+                    dependencies.push_back(binding.ObjectReference.SceneGuid);
+            }
+        }
+        for (const auto& dependency : dependencies) {
+            if (active.contains(dependency)) {
+                issues.push_back("Scene dependency cycle: " + document.SceneGuid.ToString() + " -> " + dependency.ToString());
+                continue;
+            }
+            if (visited.contains(dependency) || !Loader_) continue;
+            auto child = Loader_(dependency);
+            if (!child) issues.push_back("Missing scene dependency: " + dependency.ToString());
+            else visit(*child);
+        }
+        active.erase(document.SceneGuid);
+    };
+    visit(root);
+    return issues;
+}
+
+void MetaCoreSceneWorld::UpdateStreaming(const std::vector<glm::vec3>& sourcePositions) {
+    std::vector<MetaCoreSubSceneDocument> subScenes;
+    for (const auto& [guid, scene] : LoadedScenes_) {
+        (void)guid;
+        subScenes.insert(subScenes.end(), scene.Source.SubScenes.begin(), scene.Source.SubScenes.end());
+    }
+    for (const auto& subScene : subScenes) {
+        if (!subScene.SceneGuid.IsValid() || subScene.LoadPolicy == MetaCoreSubSceneLoadPolicy::Manual) continue;
+        bool near = subScene.LoadPolicy == MetaCoreSubSceneLoadPolicy::AlwaysLoaded;
+        bool far = !sourcePositions.empty();
+        for (const auto& source : sourcePositions) {
+            const float distance = DistanceToBounds(source, subScene.BoundsCenter, subScene.BoundsExtent);
+            near = near || distance <= subScene.PreloadDistance;
+            far = far && distance > subScene.UnloadDistance;
+        }
+        if (near && !IsSceneLoaded(subScene.SceneGuid))
+            (void)RequestLoad(subScene.SceneGuid, MetaCoreSceneLoadMode::SubScene, subScene.Priority);
+        else if (far && IsSceneLoaded(subScene.SceneGuid) && !HardResidentScenes_.contains(subScene.SceneGuid))
+            (void)UnloadScene(subScene.SceneGuid);
+    }
+}
+
+std::uint64_t MetaCoreSceneWorld::AddLifecycleListener(LifecycleListener listener) {
+    const std::uint64_t id = NextListenerId_++;
+    Listeners_.emplace(id, std::move(listener));
+    return id;
+}
+
+void MetaCoreSceneWorld::RemoveLifecycleListener(std::uint64_t listenerId) { Listeners_.erase(listenerId); }
+
+void MetaCoreSceneWorld::Publish(MetaCoreSceneLifecycleEvent event) {
+    for (const auto& [id, listener] : Listeners_) {
+        (void)id;
+        if (listener) listener(event);
+    }
+}
+
+void MetaCoreSceneWorld::RebuildObjectIndex() {
+    ObjectIndex_.clear();
+    for (const auto object : Scene_->GetGameObjects()) {
+        if (!object.HasComponent<MetaCoreSceneObjectIdentityComponent>()) continue;
+        const auto& identity = object.GetComponent<MetaCoreSceneObjectIdentityComponent>();
+        if (identity.SceneGuid.IsValid() && identity.StableObjectGuid.IsValid())
+            ObjectIndex_[{identity.SceneGuid, identity.StableObjectGuid}] = object.GetId();
+    }
+}
+
+void MetaCoreSceneWorld::RebuildHardResidency() {
+    HardResidentScenes_.clear();
+    for (const auto object : Scene_->GetGameObjects()) {
+        MetaCoreAssetGuid sourceSceneGuid{};
+        if (object.HasComponent<MetaCoreSceneObjectIdentityComponent>())
+            sourceSceneGuid = object.GetComponent<MetaCoreSceneObjectIdentityComponent>().SceneGuid;
+        if (object.HasComponent<MetaCorePhysicsConstraintComponent>()) {
+            const auto& reference = object.GetComponent<MetaCorePhysicsConstraintComponent>().TargetObjectReference;
+            if (reference.IsValid() && reference.Strength == MetaCoreObjectReferenceStrength::Hard &&
+                reference.SceneGuid != sourceSceneGuid)
+                HardResidentScenes_.insert(reference.SceneGuid);
+        }
+        if (object.HasComponent<MetaCoreTimelineDirectorComponent>()) {
+            for (const auto& binding : object.GetComponent<MetaCoreTimelineDirectorComponent>().Bindings) {
+                if (binding.ObjectReference.IsValid() &&
+                    binding.ObjectReference.Strength == MetaCoreObjectReferenceStrength::Hard &&
+                    binding.ObjectReference.SceneGuid != sourceSceneGuid)
+                    HardResidentScenes_.insert(binding.ObjectReference.SceneGuid);
+            }
+        }
+    }
+}
+
+}  // namespace MetaCore
diff --git a/Source/MetaCoreScene/Public/MetaCoreScene/MetaCoreComponents.h b/Source/MetaCoreScene/Public/MetaCoreScene/MetaCoreComponents.h
index 5b5d2fc..93c5829 100644
--- a/Source/MetaCoreScene/Public/MetaCoreScene/MetaCoreComponents.h
+++ b/Source/MetaCoreScene/Public/MetaCoreScene/MetaCoreComponents.h
@@ -4,6 +4,7 @@
 #include "MetaCoreFoundation/MetaCoreId.h"
 #include "MetaCoreFoundation/MetaCoreReflection.h"
 #include "MetaCoreRendering/MetaCoreRendering.h"
+#include "MetaCoreScene/MetaCoreObjectReference.h"
 
 #include <glm/vec3.hpp>
 #include <glm/gtc/quaternion.hpp>
@@ -309,6 +310,8 @@ struct MetaCoreTimelineBinding {
     std::string Slot{};
     MC_PROPERTY()
     MetaCoreId ObjectId = 0;
+    MC_PROPERTY()
+    MetaCoreObjectReference ObjectReference{};
 };
 
 MC_STRUCT()
@@ -467,6 +470,8 @@ struct MetaCorePhysicsConstraintComponent {
     MC_PROPERTY()
     MetaCoreId TargetObjectId = 0;
     MC_PROPERTY()
+    MetaCoreObjectReference TargetObjectReference{};
+    MC_PROPERTY()
     glm::vec3 Anchor{0.0F};
     MC_PROPERTY()
     glm::vec3 TargetAnchor{0.0F};
diff --git a/Source/MetaCoreScene/Public/MetaCoreScene/MetaCoreGameObject.h b/Source/MetaCoreScene/Public/MetaCoreScene/MetaCoreGameObject.h
index 184ac53..98d5c9c 100644
--- a/Source/MetaCoreScene/Public/MetaCoreScene/MetaCoreGameObject.h
+++ b/Source/MetaCoreScene/Public/MetaCoreScene/MetaCoreGameObject.h
@@ -25,6 +25,25 @@ struct MetaCorePrefabInstanceMetadata {
 
     MC_PROPERTY()
     MetaCoreId PrefabInstanceRootId = 0;
+
+    MC_PROPERTY()
+    MetaCoreAssetGuid InstanceGuid{};
+
+    MC_PROPERTY()
+    MetaCoreAssetGuid PrefabNodeGuid{};
+};
+
+// Runtime ownership metadata. StableObjectGuid is persisted through
+// MetaCoreGameObjectData while RuntimeId remains process-local.
+MC_STRUCT()
+struct MetaCoreSceneObjectIdentityComponent {
+    MC_GENERATED_BODY()
+
+    MC_PROPERTY()
+    MetaCoreAssetGuid SceneGuid{};
+
+    MC_PROPERTY()
+    MetaCoreAssetGuid StableObjectGuid{};
 };
 
 // Component structs for basic properties
@@ -116,6 +135,10 @@ struct MetaCoreGameObjectData {
     MC_PROPERTY()
     MetaCoreId ParentId = 0;
     MC_PROPERTY()
+    MetaCoreAssetGuid SceneGuid{};
+    MC_PROPERTY()
+    MetaCoreAssetGuid StableObjectGuid{};
+    MC_PROPERTY()
     std::string Name;
     MC_PROPERTY()
     MetaCoreTransformComponent Transform{};
diff --git a/Source/MetaCoreScene/Public/MetaCoreScene/MetaCoreObjectReference.h b/Source/MetaCoreScene/Public/MetaCoreScene/MetaCoreObjectReference.h
new file mode 100644
index 0000000..114d285
--- /dev/null
+++ b/Source/MetaCoreScene/Public/MetaCoreScene/MetaCoreObjectReference.h
@@ -0,0 +1,30 @@
+#pragma once
+
+#include "MetaCoreFoundation/MetaCoreAssetGuid.h"
+#include "MetaCoreFoundation/MetaCoreReflection.h"
+
+namespace MetaCore {
+
+MC_ENUM()
+enum class MetaCoreObjectReferenceStrength {
+    Soft = 0,
+    Hard
+};
+
+MC_STRUCT()
+struct MetaCoreObjectReference {
+    MC_GENERATED_BODY()
+
+    MC_PROPERTY()
+    MetaCoreAssetGuid SceneGuid{};
+
+    MC_PROPERTY()
+    MetaCoreAssetGuid StableObjectGuid{};
+
+    MC_PROPERTY()
+    MetaCoreObjectReferenceStrength Strength = MetaCoreObjectReferenceStrength::Soft;
+
+    [[nodiscard]] bool IsValid() const { return StableObjectGuid.IsValid(); }
+};
+
+}  // namespace MetaCore
diff --git a/Source/MetaCoreScene/Public/MetaCoreScene/MetaCorePrefab.h b/Source/MetaCoreScene/Public/MetaCoreScene/MetaCorePrefab.h
new file mode 100644
index 0000000..7998b83
--- /dev/null
+++ b/Source/MetaCoreScene/Public/MetaCoreScene/MetaCorePrefab.h
@@ -0,0 +1,64 @@
+#pragma once
+
+#include "MetaCoreScene/MetaCoreSceneDocument.h"
+
+#include <functional>
+#include <optional>
+#include <unordered_map>
+
+namespace MetaCore {
+
+struct MetaCoreResolvedPrefab {
+    MetaCorePrefabDocument Document{};
+    std::vector<MetaCorePrefabOverrideDocument> OrphanOverrides{};
+    std::vector<MetaCoreAssetGuid> DependencyChain{};
+};
+
+class MetaCorePrefabOverrideRegistry {
+public:
+    using PropertyHandler = std::function<bool(MetaCoreGameObjectData&, std::string_view, std::string_view)>;
+
+    MetaCorePrefabOverrideRegistry();
+    void RegisterPropertyHandler(std::string componentTypeId, PropertyHandler handler);
+    [[nodiscard]] bool Apply(
+        MetaCorePrefabDocument& document,
+        const MetaCorePrefabOverrideDocument& overrideValue
+    ) const;
+
+private:
+    std::unordered_map<std::string, PropertyHandler> PropertyHandlers_{};
+};
+
+class MetaCorePrefabResolver {
+public:
+    using PrefabLoader = std::function<std::optional<MetaCorePrefabDocument>(const MetaCoreAssetGuid&)>;
+
+    explicit MetaCorePrefabResolver(
+        PrefabLoader loader,
+        MetaCorePrefabOverrideRegistry registry = MetaCorePrefabOverrideRegistry{}
+    );
+
+    [[nodiscard]] std::optional<MetaCoreResolvedPrefab> Resolve(
+        const MetaCoreAssetGuid& prefabGuid,
+        std::string* error = nullptr
+    ) const;
+    [[nodiscard]] std::optional<std::vector<MetaCoreGameObjectData>> Instantiate(
+        const MetaCoreAssetGuid& prefabGuid,
+        const MetaCoreAssetGuid& instanceGuid,
+        const std::vector<MetaCorePrefabOverrideDocument>& instanceOverrides = {},
+        std::string* error = nullptr
+    ) const;
+    [[nodiscard]] std::vector<std::string> ValidateDependencies(const MetaCoreAssetGuid& prefabGuid) const;
+
+private:
+    [[nodiscard]] std::optional<MetaCoreResolvedPrefab> ResolveInternal(
+        const MetaCoreAssetGuid& prefabGuid,
+        std::vector<MetaCoreAssetGuid>& stack,
+        std::string* error
+    ) const;
+
+    PrefabLoader Loader_{};
+    MetaCorePrefabOverrideRegistry OverrideRegistry_{};
+};
+
+}  // namespace MetaCore
diff --git a/Source/MetaCoreScene/Public/MetaCoreScene/MetaCoreSceneDocument.h b/Source/MetaCoreScene/Public/MetaCoreScene/MetaCoreSceneDocument.h
index 24cb0dc..dc4c50c 100644
--- a/Source/MetaCoreScene/Public/MetaCoreScene/MetaCoreSceneDocument.h
+++ b/Source/MetaCoreScene/Public/MetaCoreScene/MetaCoreSceneDocument.h
@@ -5,6 +5,7 @@
 #include "MetaCoreFoundation/MetaCoreAssetGuid.h"
 #include "MetaCoreFoundation/MetaCoreAssetTypes.h"
 #include "MetaCoreScene/MetaCoreGameObject.h"
+#include "MetaCoreScene/MetaCoreObjectReference.h"
 #include <glm/vec3.hpp>
 
 #include <filesystem>
@@ -13,6 +14,125 @@
 
 namespace MetaCore {
 
+inline constexpr std::uint32_t GMetaCoreSceneSchemaVersion = 2U;
+inline constexpr std::uint32_t GMetaCorePrefabSchemaVersion = 2U;
+
+MC_ENUM()
+enum class MetaCoreSubSceneLoadPolicy {
+    AlwaysLoaded = 0,
+    Manual,
+    Distance
+};
+
+MC_STRUCT()
+struct MetaCoreSubSceneDocument {
+    MC_GENERATED_BODY()
+
+    MC_PROPERTY()
+    MetaCoreAssetGuid SceneGuid{};
+
+    MC_PROPERTY()
+    std::filesystem::path ScenePath{};
+
+    MC_PROPERTY()
+    MetaCoreSubSceneLoadPolicy LoadPolicy = MetaCoreSubSceneLoadPolicy::AlwaysLoaded;
+
+    MC_PROPERTY()
+    glm::vec3 BoundsCenter{0.0F};
+
+    MC_PROPERTY()
+    glm::vec3 BoundsExtent{0.0F};
+
+    MC_PROPERTY()
+    glm::vec3 CellCoordinate{0.0F};
+
+    MC_PROPERTY()
+    float PreloadDistance = 100.0F;
+
+    MC_PROPERTY()
+    float UnloadDistance = 125.0F;
+
+    MC_PROPERTY()
+    std::int32_t Priority = 0;
+};
+
+MC_STRUCT()
+struct MetaCoreSchemaVersionEntry {
+    MC_GENERATED_BODY()
+
+    MC_PROPERTY()
+    std::string TypeId{};
+
+    MC_PROPERTY()
+    std::uint32_t Version = 1U;
+};
+
+MC_ENUM()
+enum class MetaCorePrefabOverrideOperation {
+    SetProperty = 0,
+    AddComponent,
+    RemoveComponent,
+    AddChild,
+    RemoveChild,
+    Reparent
+};
+
+MC_STRUCT()
+struct MetaCorePrefabOverrideDocument {
+    MC_GENERATED_BODY()
+
+    MC_PROPERTY()
+    MetaCoreAssetGuid TargetNodeGuid{};
+
+    MC_PROPERTY()
+    std::string ComponentTypeId{};
+
+    MC_PROPERTY()
+    std::string PropertyPath{};
+
+    MC_PROPERTY()
+    MetaCorePrefabOverrideOperation Operation = MetaCorePrefabOverrideOperation::SetProperty;
+
+    // Canonical JSON value. Keeping the value self-describing allows component
+    // serializers to migrate it without coupling prefab documents to C++ layout.
+    MC_PROPERTY()
+    std::string ValueJson{};
+};
+
+MC_STRUCT()
+struct MetaCoreNestedPrefabDocument {
+    MC_GENERATED_BODY()
+
+    MC_PROPERTY()
+    MetaCoreAssetGuid MountNodeGuid{};
+
+    MC_PROPERTY()
+    MetaCoreAssetGuid PrefabAssetGuid{};
+
+    MC_PROPERTY()
+    MetaCoreAssetGuid InstanceGuid{};
+
+    MC_PROPERTY()
+    std::vector<MetaCorePrefabOverrideDocument> Overrides{};
+};
+
+MC_STRUCT()
+struct MetaCorePrefabInstanceDocument {
+    MC_GENERATED_BODY()
+
+    MC_PROPERTY()
+    MetaCoreAssetGuid InstanceGuid{};
+
+    MC_PROPERTY()
+    MetaCoreAssetGuid PrefabAssetGuid{};
+
+    MC_PROPERTY()
+    MetaCoreAssetGuid ParentObjectGuid{};
+
+    MC_PROPERTY()
+    std::vector<MetaCorePrefabOverrideDocument> Overrides{};
+};
+
 MC_STRUCT()
 struct MetaCoreEditorSelectionSnapshot {
     MC_GENERATED_BODY()
@@ -69,6 +189,12 @@ MC_STRUCT()
 struct MetaCoreSceneDocument {
     MC_GENERATED_BODY()
 
+    MC_PROPERTY()
+    std::uint32_t SchemaVersion = GMetaCoreSceneSchemaVersion;
+
+    MC_PROPERTY()
+    MetaCoreAssetGuid SceneGuid{};
+
     MC_PROPERTY()
     std::string Name{};
 
@@ -78,6 +204,15 @@ struct MetaCoreSceneDocument {
     MC_PROPERTY()
     std::vector<MetaCoreGameObjectData> GameObjects{};
 
+    MC_PROPERTY()
+    std::vector<MetaCoreSubSceneDocument> SubScenes{};
+
+    MC_PROPERTY()
+    std::vector<MetaCorePrefabInstanceDocument> PrefabInstances{};
+
+    MC_PROPERTY()
+    std::vector<MetaCoreSchemaVersionEntry> ComponentVersions{};
+
     MC_PROPERTY()
     MetaCoreEditorSelectionSnapshot Selection{};
 };
@@ -86,11 +221,29 @@ MC_STRUCT()
 struct MetaCorePrefabDocument {
     MC_GENERATED_BODY()
 
+    MC_PROPERTY()
+    std::uint32_t SchemaVersion = GMetaCorePrefabSchemaVersion;
+
+    MC_PROPERTY()
+    MetaCoreAssetGuid PrefabGuid{};
+
+    MC_PROPERTY()
+    MetaCoreAssetGuid BasePrefabGuid{};
+
     MC_PROPERTY()
     std::string Name{};
 
     MC_PROPERTY()
     std::vector<MetaCoreGameObjectData> GameObjects{};
+
+    MC_PROPERTY()
+    std::vector<MetaCoreNestedPrefabDocument> NestedPrefabs{};
+
+    MC_PROPERTY()
+    std::vector<MetaCorePrefabOverrideDocument> Overrides{};
+
+    MC_PROPERTY()
+    std::vector<MetaCoreSchemaVersionEntry> ComponentVersions{};
 };
 
 MC_ENUM()
diff --git a/Source/MetaCoreScene/Public/MetaCoreScene/MetaCoreSceneWorld.h b/Source/MetaCoreScene/Public/MetaCoreScene/MetaCoreSceneWorld.h
new file mode 100644
index 0000000..5f7819f
--- /dev/null
+++ b/Source/MetaCoreScene/Public/MetaCoreScene/MetaCoreSceneWorld.h
@@ -0,0 +1,175 @@
+#pragma once
+
+#include "MetaCoreScene/MetaCoreScene.h"
+
+#include <chrono>
+#include <functional>
+#include <future>
+#include <memory>
+#include <optional>
+#include <unordered_map>
+#include <unordered_set>
+
+namespace MetaCore {
+
+enum class MetaCoreSceneLoadMode {
+    Replace = 0,
+    Additive,
+    SubScene
+};
+
+enum class MetaCoreSceneLoadState {
+    Unloaded = 0,
+    Loading,
+    Loaded,
+    Failed,
+    Cancelled
+};
+
+enum class MetaCoreSceneLifecycleEventType {
+    BeforeUnload = 0,
+    AfterUnload,
+    AfterLoad
+};
+
+struct MetaCoreSceneLifecycleEvent {
+    MetaCoreSceneLifecycleEventType Type = MetaCoreSceneLifecycleEventType::AfterLoad;
+    MetaCoreAssetGuid SceneGuid{};
+    std::vector<MetaCoreId> ObjectIds{};
+};
+
+struct MetaCoreSceneLoadStatus {
+    std::uint64_t RequestId = 0;
+    MetaCoreAssetGuid SceneGuid{};
+    MetaCoreSceneLoadState State = MetaCoreSceneLoadState::Unloaded;
+    std::string Error{};
+};
+
+struct MetaCoreSceneWorldSettings {
+    double MainThreadCommitBudgetMilliseconds = 2.0;
+    std::size_t MemoryBudgetBytes = 512U * 1024U * 1024U;
+};
+
+struct MetaCoreLoadedSceneInfo {
+    MetaCoreAssetGuid SceneGuid{};
+    std::string Name{};
+    MetaCoreSceneLoadMode LoadMode = MetaCoreSceneLoadMode::Additive;
+    bool Active = false;
+    bool Dirty = false;
+    bool HardResident = false;
+    std::vector<MetaCoreId> RuntimeObjectIds{};
+};
+
+struct MetaCoreSceneWorldSnapshotEntry {
+    MetaCoreSceneDocument Document{};
+    MetaCoreSceneLoadMode LoadMode = MetaCoreSceneLoadMode::Additive;
+    bool Dirty = false;
+};
+
+struct MetaCoreSceneWorldSnapshot {
+    MetaCoreSceneSnapshot CompositeScene{};
+    MetaCoreAssetGuid ActiveSceneGuid{};
+    std::vector<MetaCoreSceneWorldSnapshotEntry> Scenes{};
+};
+
+class MetaCoreSceneWorld {
+public:
+    using SceneLoader = std::function<std::optional<MetaCoreSceneDocument>(const MetaCoreAssetGuid&)>;
+    using LifecycleListener = std::function<void(const MetaCoreSceneLifecycleEvent&)>;
+
+    explicit MetaCoreSceneWorld(SceneLoader loader = {}, MetaCoreSceneWorldSettings settings = {});
+    MetaCoreSceneWorld(MetaCoreScene& scene, SceneLoader loader = {}, MetaCoreSceneWorldSettings settings = {});
+    ~MetaCoreSceneWorld();
+
+    MetaCoreSceneWorld(const MetaCoreSceneWorld&) = delete;
+    MetaCoreSceneWorld& operator=(const MetaCoreSceneWorld&) = delete;
+
+    [[nodiscard]] MetaCoreScene& GetScene() { return *Scene_; }
+    [[nodiscard]] const MetaCoreScene& GetScene() const { return *Scene_; }
+
+    void SetSceneLoader(SceneLoader loader);
+    [[nodiscard]] std::uint64_t RequestLoad(
+        const MetaCoreAssetGuid& sceneGuid,
+        MetaCoreSceneLoadMode mode = MetaCoreSceneLoadMode::Additive,
+        std::int32_t priority = 0
+    );
+    [[nodiscard]] bool CancelLoad(std::uint64_t requestId);
+    void Tick();
+    void UpdateStreaming(const std::vector<glm::vec3>& sourcePositions);
+
+    [[nodiscard]] bool LoadDocumentNow(
+        MetaCoreSceneDocument document,
+        MetaCoreSceneLoadMode mode = MetaCoreSceneLoadMode::Additive,
+        std::string* error = nullptr
+    );
+    [[nodiscard]] bool UnloadScene(const MetaCoreAssetGuid& sceneGuid, bool force = false);
+    [[nodiscard]] bool SetActiveScene(const MetaCoreAssetGuid& sceneGuid);
+    [[nodiscard]] MetaCoreAssetGuid GetActiveSceneGuid() const { return ActiveSceneGuid_; }
+    [[nodiscard]] bool IsSceneLoaded(const MetaCoreAssetGuid& sceneGuid) const;
+    [[nodiscard]] std::vector<MetaCoreLoadedSceneInfo> GetLoadedScenes() const;
+    [[nodiscard]] std::optional<MetaCoreSceneLoadStatus> GetLoadStatus(std::uint64_t requestId) const;
+
+    [[nodiscard]] MetaCoreGameObject ResolveObject(const MetaCoreObjectReference& reference);
+    [[nodiscard]] MetaCoreGameObject ResolveObject(const MetaCoreObjectReference& reference) const;
+    [[nodiscard]] MetaCoreObjectReference BuildObjectReference(
+        MetaCoreId runtimeObjectId,
+        MetaCoreObjectReferenceStrength strength = MetaCoreObjectReferenceStrength::Soft
+    ) const;
+
+    [[nodiscard]] bool MoveSubtreeToScene(MetaCoreId rootObjectId, const MetaCoreAssetGuid& targetSceneGuid);
+    [[nodiscard]] std::optional<MetaCoreSceneDocument> CaptureSceneDocument(const MetaCoreAssetGuid& sceneGuid) const;
+    [[nodiscard]] MetaCoreSceneWorldSnapshot CaptureWorldSnapshot() const;
+    void RestoreWorldSnapshot(const MetaCoreSceneWorldSnapshot& snapshot);
+    [[nodiscard]] std::vector<std::string> ValidateDependencies(const MetaCoreSceneDocument& root) const;
+
+    std::uint64_t AddLifecycleListener(LifecycleListener listener);
+    void RemoveLifecycleListener(std::uint64_t listenerId);
+
+private:
+    struct ObjectKey {
+        MetaCoreAssetGuid SceneGuid{};
+        MetaCoreAssetGuid ObjectGuid{};
+        bool operator==(const ObjectKey&) const = default;
+    };
+    struct ObjectKeyHasher {
+        std::size_t operator()(const ObjectKey& value) const noexcept;
+    };
+    struct LoadedScene {
+        MetaCoreSceneDocument Source{};
+        MetaCoreSceneLoadMode LoadMode = MetaCoreSceneLoadMode::Additive;
+        std::vector<MetaCoreId> RuntimeObjectIds{};
+        std::unordered_map<MetaCoreId, MetaCoreId> RuntimeToSerializedId{};
+        bool Dirty = false;
+    };
+    struct PendingLoad;
+
+    [[nodiscard]] bool CommitDocument(MetaCoreSceneDocument document, MetaCoreSceneLoadMode mode, std::string* error);
+    void Publish(MetaCoreSceneLifecycleEvent event);
+    void RebuildObjectIndex();
+    void RebuildHardResidency();
+
+    SceneLoader Loader_{};
+    MetaCoreSceneWorldSettings Settings_{};
+    std::unique_ptr<MetaCoreScene> OwnedScene_{};
+    MetaCoreScene* Scene_ = nullptr;
+    MetaCoreAssetGuid ActiveSceneGuid_{};
+    std::unordered_map<MetaCoreAssetGuid, LoadedScene, MetaCoreAssetGuidHasher> LoadedScenes_{};
+    std::unordered_map<ObjectKey, MetaCoreId, ObjectKeyHasher> ObjectIndex_{};
+    std::unordered_set<MetaCoreAssetGuid, MetaCoreAssetGuidHasher> HardResidentScenes_{};
+    std::vector<std::unique_ptr<PendingLoad>> PendingLoads_{};
+    std::unordered_map<std::uint64_t, MetaCoreSceneLoadStatus> LoadStatuses_{};
+    std::unordered_map<std::uint64_t, LifecycleListener> Listeners_{};
+    std::uint64_t NextRequestId_ = 1;
+    std::uint64_t NextListenerId_ = 1;
+};
+
+[[nodiscard]] MetaCoreAssetGuid MetaCoreBuildDeterministicGuid(
+    const MetaCoreAssetGuid& namespaceGuid,
+    const MetaCoreAssetGuid& localGuid
+);
+[[nodiscard]] MetaCoreAssetGuid MetaCoreBuildDeterministicGuid(
+    const MetaCoreAssetGuid& namespaceGuid,
+    std::uint64_t localValue
+);
+
+}  // namespace MetaCore
diff --git a/docs/designs/metacore-mature-engine-gap-and-work-plan.md b/docs/designs/metacore-mature-engine-gap-and-work-plan.md
index 2db764f..f11fc98 100644
--- a/docs/designs/metacore-mature-engine-gap-and-work-plan.md
+++ b/docs/designs/metacore-mature-engine-gap-and-work-plan.md
@@ -359,14 +359,25 @@ R8.1–R8.5 已落地的工程边界：
 
 ### 10. Scene 与 Prefab
 
-需要补齐：
+已完成：
 
-- [ ] 多场景编辑、Additive Load、SubScene 和异步流式加载。
-- [ ] 大场景分区、按需加载和场景依赖检查。
-- [ ] 嵌套 Prefab、Prefab Variant 和实例同步。
-- [ ] 细粒度 Override 记录、可视化、Apply 和 Revert。
-- [ ] 跨场景对象引用规则。
-- [ ] Scene、Component、Prefab 的格式版本迁移机制。
+- [x] 多场景编辑、Additive Load、SubScene 和异步流式加载。
+- [x] 大场景分区、按需加载和场景依赖检查。
+- [x] 嵌套 Prefab、Prefab Variant 和实例同步。
+- [x] 细粒度 Override 记录、可视化、Apply 和 Revert。
+- [x] 跨场景对象引用规则。
+- [x] Scene、Component、Prefab 的格式版本迁移机制。
+
+实现与验收基线（2026-07-27）：
+
+- 新增 `MetaCoreSceneWorld`，在一个组合 ECS 上管理 Replace/Additive/SubScene、活动 Scene、Scene Set 快照、异步请求去重/取消、优先级、距离迟滞、Hard 驻留、生命周期事件和限定对象引用；Play/Stop 会恢复完整 Scene Set、活动 Scene、对象 ID、选择与 Dirty 状态。
+- Scene/Prefab Schema 升级到版本 2，持久化 Scene/Prefab/对象/Prefab 节点 GUID、SubScene Cell 元数据、组件版本、Prefab Base/嵌套关系和属性/组件/结构 Override。旧文档缺失 GUID 时使用确定性迁移，高版本文档拒绝加载，Cooked Package 同步写入 `CustomVersions` 与依赖表。
+- Prefab 解析顺序固定为 Base → Variant → 嵌套 Prefab → Scene Instance Override；循环与缺失依赖拒绝解析，孤立 Override 可诊断，相同 Instance GUID 重复展开得到相同稳定对象 GUID。Override 注册表覆盖属性、组件增删、子对象增删和重挂接，编辑器继续提供字段级 Apply/Revert 与 Override 标记。
+- Editor Hierarchy 按 Scene 分组并提供 Set Active、Unload、Save All 和 Additive Open；新对象归属活动 Scene，跨 Scene 直接父子关系被拒绝，跨场景移动通过 World 事务完成。根 Scene Environment 不被活动 Scene 覆盖。
+- Cook 从启动 Scene 遍历 SubScene、Hard Scene 引用和 Prefab Base/Variant/嵌套依赖，缺失或循环在打包阶段失败；运行时清单记录 Scene GUID、包路径、Hash 和依赖，Player 与 Editor 共用 `MetaCoreSceneWorld` 的 AlwaysLoaded/Distance 流式规则。
+- 新增 `MetaCoreSceneTests` 与 `MetaCoreSceneBenchmark`。Linux x86_64 Development 全量 CTest **14/14** 通过；10,000 对象基准实测 load **35.36–37.10 ms**、capture p95 **8.99–12.17 ms**、100 节点 Prefab 展开 p95 **0.027–0.031 ms**，持续门禁按签收上界约 120% 设置为 **45 ms / 15 ms / 0.04 ms**。
+
+首版边界保持为显式 SubScene 加可选网格 Cell，不做编辑器自动世界切分；正式关闭平台为 Linux x86_64，Windows 仅保留可编译接口。
 
 ### 11. 编辑器生产力与插件边界
 
diff --git a/tests/MetaCoreDeliveryTests.cpp b/tests/MetaCoreDeliveryTests.cpp
index 79686e1..7e57b20 100644
--- a/tests/MetaCoreDeliveryTests.cpp
+++ b/tests/MetaCoreDeliveryTests.cpp
@@ -52,6 +52,12 @@ int main() {
     delivery.BuildId = "test-build";
     delivery.StartupScene = "payload.bin";
     delivery.ScriptModules.push_back("Project/Scripts/TestScripts.so");
+    MetaCore::MetaCoreRuntimeDeliveryDocument::SceneEntry sceneEntry;
+    sceneEntry.SceneGuid = MetaCore::MetaCoreAssetGuid::Generate();
+    sceneEntry.PackagePath = "Content/Scenes/root.mcscene";
+    sceneEntry.SourceHash = 42;
+    sceneEntry.Dependencies.push_back(MetaCore::MetaCoreAssetGuid::Generate());
+    delivery.ScenePackages.push_back(sceneEntry);
     WriteText(package / delivery.ScriptModules.front(), "script");
     Expect(MetaCore::MetaCoreWriteRuntimeDeliveryDocument(package / "Project" / "MetaCore.runtimeproject", delivery), "write runtime delivery");
     MetaCore::MetaCoreReleaseManifestDocument manifest;
@@ -67,6 +73,10 @@ int main() {
     Expect(MetaCore::MetaCoreValidateReleasePackage(package).empty(), "valid package accepted");
     const auto readDelivery = MetaCore::MetaCoreReadRuntimeDeliveryDocument(package / "Project" / "MetaCore.runtimeproject");
     Expect(readDelivery.has_value() && readDelivery->ScriptModules == delivery.ScriptModules, "runtime delivery preserves script module paths");
+    Expect(readDelivery && readDelivery->ScenePackages.size() == 1 &&
+        readDelivery->ScenePackages[0].SceneGuid == sceneEntry.SceneGuid &&
+        readDelivery->ScenePackages[0].Dependencies == sceneEntry.Dependencies,
+        "runtime delivery preserves scene dependency manifest");
     WriteText(package / "payload.bin", "tampered");
     const auto corruptIssues = MetaCore::MetaCoreValidateReleasePackage(package);
     Expect(!corruptIssues.empty(), "corrupt package rejected");
diff --git a/tests/MetaCoreSceneBenchmark.cpp b/tests/MetaCoreSceneBenchmark.cpp
new file mode 100644
index 0000000..7dfb2a0
--- /dev/null
+++ b/tests/MetaCoreSceneBenchmark.cpp
@@ -0,0 +1,81 @@
+#include "MetaCoreScene/MetaCorePrefab.h"
+#include "MetaCoreScene/MetaCoreSceneWorld.h"
+
+#include <algorithm>
+#include <chrono>
+#include <cstdlib>
+#include <iostream>
+#include <vector>
+
+namespace {
+
+double MillisecondsSince(std::chrono::steady_clock::time_point begin) {
+    return std::chrono::duration<double, std::milli>(std::chrono::steady_clock::now() - begin).count();
+}
+
+}  // namespace
+
+int main() {
+    using namespace MetaCore;
+
+    MetaCoreSceneDocument largeScene;
+    largeScene.SceneGuid = MetaCoreAssetGuid::Generate();
+    largeScene.Name = "SceneBenchmark";
+    constexpr std::size_t objectCount = 10000;
+    largeScene.GameObjects.reserve(objectCount);
+    for (std::size_t index = 0; index < objectCount; ++index) {
+        MetaCoreGameObjectData object;
+        object.Id = index + 1;
+        object.ParentId = index == 0 ? 0 : (index / 10) + 1;
+        if (object.ParentId == object.Id) object.ParentId = 0;
+        object.SceneGuid = largeScene.SceneGuid;
+        object.StableObjectGuid = MetaCoreBuildDeterministicGuid(largeScene.SceneGuid, object.Id);
+        object.Name = "Object_" + std::to_string(index);
+        largeScene.GameObjects.push_back(std::move(object));
+    }
+
+    MetaCoreSceneWorld world;
+    const auto loadBegin = std::chrono::steady_clock::now();
+    if (!world.LoadDocumentNow(largeScene, MetaCoreSceneLoadMode::Replace)) return EXIT_FAILURE;
+    const double loadMilliseconds = MillisecondsSince(loadBegin);
+
+    std::vector<double> captureSamples;
+    captureSamples.reserve(40);
+    for (int sample = 0; sample < 40; ++sample) {
+        const auto begin = std::chrono::steady_clock::now();
+        if (!world.CaptureSceneDocument(largeScene.SceneGuid)) return EXIT_FAILURE;
+        captureSamples.push_back(MillisecondsSince(begin));
+    }
+    std::sort(captureSamples.begin(), captureSamples.end());
+    const double captureP95 = captureSamples[static_cast<std::size_t>(captureSamples.size() * 0.95)];
+
+    MetaCorePrefabDocument prefab;
+    prefab.PrefabGuid = MetaCoreAssetGuid::Generate();
+    prefab.Name = "BenchmarkPrefab";
+    prefab.GameObjects.assign(largeScene.GameObjects.begin(), largeScene.GameObjects.begin() + 100);
+    MetaCorePrefabResolver resolver([&](const MetaCoreAssetGuid& guid) -> std::optional<MetaCorePrefabDocument> {
+        return guid == prefab.PrefabGuid ? std::optional(prefab) : std::nullopt;
+    });
+    std::vector<double> prefabSamples;
+    prefabSamples.reserve(100);
+    for (int sample = 0; sample < 100; ++sample) {
+        const auto begin = std::chrono::steady_clock::now();
+        if (!resolver.Instantiate(prefab.PrefabGuid, MetaCoreAssetGuid::Generate())) return EXIT_FAILURE;
+        prefabSamples.push_back(MillisecondsSince(begin));
+    }
+    std::sort(prefabSamples.begin(), prefabSamples.end());
+    const double prefabP95 = prefabSamples[static_cast<std::size_t>(prefabSamples.size() * 0.95)];
+
+    std::cout << "SceneBenchmark objects=" << objectCount
+              << " load_ms=" << loadMilliseconds
+              << " capture_p95_ms=" << captureP95
+              << " prefab100_p95_ms=" << prefabP95 << '\n';
+    // Linux x86_64 signed baseline (2026-07-27): load 37.10 ms,
+    // capture p95 12.17 ms, prefab(100 nodes) p95 0.031 ms. Gates are
+    // rounded up from 120% to avoid sub-microsecond timer noise.
+    if (loadMilliseconds > 45.0 || captureP95 > 15.0 || prefabP95 > 0.04) {
+        std::cerr << "Scene/Prefab benchmark exceeded Linux x86_64 regression gate\n";
+        return EXIT_FAILURE;
+    }
+    return EXIT_SUCCESS;
+}
diff --git a/tests/MetaCoreSceneTests.cpp b/tests/MetaCoreSceneTests.cpp
new file mode 100644
index 0000000..4c0447d
--- /dev/null
+++ b/tests/MetaCoreSceneTests.cpp
@@ -0,0 +1,306 @@
+#include "MetaCoreScene/MetaCorePrefab.h"
+#include "MetaCoreScene/MetaCoreScenePackage.h"
+#include "MetaCoreScene/MetaCoreSceneSerializer.h"
+#include "MetaCoreScene/MetaCoreSceneWorld.h"
+#include "MetaCoreFoundation/MetaCorePackage.h"
+
+#include <chrono>
+#include <filesystem>
+#include <iostream>
+#include <thread>
+#include <unordered_map>
+
+namespace {
+
+using namespace MetaCore;
+
+void Expect(bool condition, const char* message) {
+    if (!condition) {
+        std::cerr << "FAILED: " << message << '\n';
+        std::exit(1);
+    }
+}
+
+MetaCoreSceneDocument MakeScene(const char* name, std::size_t objectCount = 1) {
+    MetaCoreSceneDocument document;
+    document.SceneGuid = MetaCoreAssetGuid::Generate();
+    document.Name = name;
+    for (std::size_t index = 0; index < objectCount; ++index) {
+        MetaCoreGameObjectData object;
+        object.Id = index + 1;
+        object.ParentId = index == 0 ? 0 : index;
+        object.SceneGuid = document.SceneGuid;
+        object.StableObjectGuid = MetaCoreBuildDeterministicGuid(document.SceneGuid, object.Id);
+        object.Name = std::string(name) + std::to_string(index);
+        document.GameObjects.push_back(std::move(object));
+    }
+    return document;
+}
+
+void TickUntilSettled(MetaCoreSceneWorld& world, std::uint64_t request) {
+    for (int iteration = 0; iteration < 1000; ++iteration) {
+        world.Tick();
+        const auto status = world.GetLoadStatus(request);
+        if (status && status->State != MetaCoreSceneLoadState::Loading) return;
+        std::this_thread::yield();
+    }
+    Expect(false, "asynchronous scene request did not settle");
+}
+
+void TestSceneJsonAndPackageVersions() {
+    const auto root = std::filesystem::temp_directory_path() / "MetaCoreSceneTests";
+    std::filesystem::create_directories(root);
+    const auto jsonPath = root / "Versioned.mcscene.json";
+    const auto packagePath = root / "Versioned.mcscene";
+    auto document = MakeScene("Versioned", 2);
+    MetaCoreSubSceneDocument sub;
+    sub.SceneGuid = MetaCoreAssetGuid::Generate();
+    sub.ScenePath = "Scenes/Cell.mcscene.json";
+    sub.LoadPolicy = MetaCoreSubSceneLoadPolicy::Distance;
+    sub.PreloadDistance = 25.0F;
+    sub.UnloadDistance = 30.0F;
+    document.SubScenes.push_back(sub);
+    document.ComponentVersions.push_back({"Transform", 2});
+
+    const auto registry = MetaCoreBuildScenePackageTypeRegistry();
+    Expect(MetaCoreSceneSerializer::SaveSceneToJson(jsonPath, document, registry), "versioned scene JSON save");
+    const auto jsonLoaded = MetaCoreSceneSerializer::LoadSceneFromJson(jsonPath, registry);
+    Expect(jsonLoaded && jsonLoaded->SchemaVersion == GMetaCoreSceneSchemaVersion, "scene JSON version round trip");
+    Expect(jsonLoaded->SceneGuid == document.SceneGuid, "scene GUID round trip");
+    Expect(jsonLoaded->GameObjects[1].StableObjectGuid == document.GameObjects[1].StableObjectGuid, "stable object GUID round trip");
+    Expect(jsonLoaded->SubScenes.size() == 1 && jsonLoaded->SubScenes[0].SceneGuid == sub.SceneGuid, "SubScene JSON round trip");
+
+    MetaCorePrefabDocument prefab;
+    prefab.Name = "VersionedPrefab";
+    prefab.PrefabGuid = MetaCoreAssetGuid::Generate();
+    prefab.GameObjects = document.GameObjects;
+    prefab.GameObjects[0].SceneGuid = {};
+    prefab.GameObjects[1].SceneGuid = {};
+    prefab.Overrides.push_back({
+        prefab.GameObjects[0].StableObjectGuid, "Name", "Value",
+        MetaCorePrefabOverrideOperation::SetProperty, "\"Renamed\""
+    });
+    const auto prefabPath = root / "Versioned.mcprefab.json";
+    Expect(MetaCoreSceneSerializer::SavePrefabToJson(prefabPath, prefab, registry), "versioned prefab JSON save");
+    const auto prefabLoaded = MetaCoreSceneSerializer::LoadPrefabFromJson(prefabPath, registry);
+    Expect(prefabLoaded && prefabLoaded->SchemaVersion == GMetaCorePrefabSchemaVersion,
+        "prefab JSON version round trip");
+    Expect(prefabLoaded->PrefabGuid == prefab.PrefabGuid && prefabLoaded->Overrides.size() == 1,
+        "prefab GUID and override round trip");
+
+    MetaCoreSceneDocument legacy;
+    legacy.Name = "LegacyDeterministic";
+    legacy.GameObjects.push_back(MetaCoreGameObjectData{});
+    legacy.GameObjects[0].Id = 42;
+    const auto legacyFirstPath = root / "LegacyFirst.mcscene.json";
+    const auto legacySecondPath = root / "LegacySecond.mcscene.json";
+    Expect(MetaCoreSceneSerializer::SaveSceneToJson(legacyFirstPath, legacy, registry), "legacy scene first migration save");
+    Expect(MetaCoreSceneSerializer::SaveSceneToJson(legacySecondPath, legacy, registry), "legacy scene second migration save");
+    const auto legacyFirst = MetaCoreSceneSerializer::LoadSceneFromJson(legacyFirstPath, registry);
+    const auto legacySecond = MetaCoreSceneSerializer::LoadSceneFromJson(legacySecondPath, registry);
+    Expect(legacyFirst && legacySecond && legacyFirst->SceneGuid == legacySecond->SceneGuid,
+        "legacy scene GUID migration is deterministic");
+    Expect(legacyFirst->GameObjects[0].StableObjectGuid == legacySecond->GameObjects[0].StableObjectGuid,
+        "legacy object GUID migration is deterministic");
+
+    Expect(MetaCoreWriteScenePackage(packagePath, document), "versioned scene package save");
+    const auto packageLoaded = MetaCoreReadScenePackage(packagePath);
+    Expect(packageLoaded && packageLoaded->SceneGuid == document.SceneGuid, "scene package round trip");
+    const auto package = MetaCoreReadPackageFile(packagePath, registry);
+    Expect(package && package->Header.PackageGuid == document.SceneGuid, "scene package uses scene GUID");
+    Expect(package->Dependencies.size() == 1 && package->Dependencies[0].AssetGuid == sub.SceneGuid, "scene package dependency table");
+    Expect(!package->CustomVersions.empty() && package->CustomVersions[0].Key == "MetaCore.Scene", "scene package custom version");
+}
+
+void TestAdditiveWorldAndQualifiedReferences() {
+    auto first = MakeScene("Root", 2);
+    auto second = MakeScene("Cell", 1);
+    first.GameObjects[0].PhysicsConstraint = MetaCorePhysicsConstraintComponent{};
+    first.GameObjects[0].PhysicsConstraint->TargetObjectReference = {
+        second.SceneGuid,
+        second.GameObjects[0].StableObjectGuid,
+        MetaCoreObjectReferenceStrength::Hard
+    };
+
+    std::unordered_map<MetaCoreAssetGuid, MetaCoreSceneDocument, MetaCoreAssetGuidHasher> documents;
+    documents.emplace(second.SceneGuid, second);
+    MetaCoreSceneWorld world([&](const MetaCoreAssetGuid& guid) -> std::optional<MetaCoreSceneDocument> {
+        const auto iterator = documents.find(guid);
+        return iterator == documents.end() ? std::nullopt : std::optional(iterator->second);
+    });
+
+    Expect(world.LoadDocumentNow(first, MetaCoreSceneLoadMode::Replace), "replace load root scene");
+    const auto sourceRoot = world.ResolveObject({
+        first.SceneGuid, first.GameObjects[0].StableObjectGuid, MetaCoreObjectReferenceStrength::Soft
+    });
+    Expect(sourceRoot, "source root resolves before additive load");
+    Expect(world.GetLoadedScenes().size() == 1 && world.GetScene().GetGameObjects().size() == 2, "root scene object count");
+    const auto requestStatusesBefore = world.GetLoadedScenes();
+    (void)requestStatusesBefore;
+    for (int iteration = 0; iteration < 1000 && !world.IsSceneLoaded(second.SceneGuid); ++iteration) {
+        world.Tick();
+        std::this_thread::yield();
+    }
+    Expect(world.IsSceneLoaded(second.SceneGuid), "hard reference loads target scene");
+    Expect(world.GetScene().GetGameObjects().size() == 3, "additive objects share composite ECS");
+    Expect(!world.UnloadScene(second.SceneGuid), "hard referenced scene cannot unload");
+
+    const auto targetReference = MetaCoreObjectReference{
+        second.SceneGuid,
+        second.GameObjects[0].StableObjectGuid,
+        MetaCoreObjectReferenceStrength::Soft
+    };
+    const auto target = world.ResolveObject(targetReference);
+    Expect(target, "qualified object reference resolves");
+    const auto rebuilt = world.BuildObjectReference(target.GetId());
+    Expect(rebuilt.SceneGuid == second.SceneGuid && rebuilt.StableObjectGuid == targetReference.StableObjectGuid,
+        "runtime object builds stable qualified reference");
+
+    const auto captured = world.CaptureSceneDocument(first.SceneGuid);
+    Expect(captured && captured->GameObjects.size() == 2, "capture filters one loaded scene");
+    Expect(world.SetActiveScene(second.SceneGuid) && world.GetActiveSceneGuid() == second.SceneGuid, "active additive scene");
+    Expect(world.MoveSubtreeToScene(sourceRoot.GetId(), second.SceneGuid), "move subtree across scenes");
+    const auto movedCapture = world.CaptureSceneDocument(second.SceneGuid);
+    Expect(movedCapture && movedCapture->GameObjects.size() == 3, "move subtree updates target scene ownership");
+    const auto worldSnapshot = world.CaptureWorldSnapshot();
+    Expect(world.UnloadScene(first.SceneGuid, true), "hard reference source can force unload");
+    Expect(world.UnloadScene(second.SceneGuid), "hard residency releases after reference source unloads");
+    world.RestoreWorldSnapshot(worldSnapshot);
+    Expect(world.GetLoadedScenes().size() == 2 && world.GetScene().GetGameObjects().size() == 3,
+        "world snapshot restores complete scene set");
+    Expect(world.GetActiveSceneGuid() == second.SceneGuid, "world snapshot restores active scene");
+}
+
+void TestAsynchronousLoadCancelAndStreaming() {
+    auto root = MakeScene("StreamingRoot");
+    auto cell = MakeScene("StreamingCell");
+    MetaCoreSubSceneDocument sub;
+    sub.SceneGuid = cell.SceneGuid;
+    sub.LoadPolicy = MetaCoreSubSceneLoadPolicy::Distance;
+    sub.BoundsCenter = {100.0F, 0.0F, 0.0F};
+    sub.BoundsExtent = {5.0F, 5.0F, 5.0F};
+    sub.PreloadDistance = 10.0F;
+    sub.UnloadDistance = 20.0F;
+    root.SubScenes.push_back(sub);
+
+    MetaCoreSceneWorld world([cell](const MetaCoreAssetGuid& guid) -> std::optional<MetaCoreSceneDocument> {
+        return guid == cell.SceneGuid ? std::optional(cell) : std::nullopt;
+    });
+    Expect(world.LoadDocumentNow(root, MetaCoreSceneLoadMode::Replace), "streaming root load");
+    world.UpdateStreaming({glm::vec3(90.0F, 0.0F, 0.0F)});
+    for (int iteration = 0; iteration < 1000 && !world.IsSceneLoaded(cell.SceneGuid); ++iteration) {
+        world.Tick();
+        std::this_thread::yield();
+    }
+    Expect(world.IsSceneLoaded(cell.SceneGuid), "distance cell loads near threshold");
+    world.UpdateStreaming({glm::vec3(111.0F, 0.0F, 0.0F)});
+    Expect(world.IsSceneLoaded(cell.SceneGuid), "distance hysteresis keeps cell before unload threshold");
+    world.UpdateStreaming({glm::vec3(130.0F, 0.0F, 0.0F)});
+    Expect(!world.IsSceneLoaded(cell.SceneGuid), "distance cell unloads beyond threshold");
+
+    const auto request = world.RequestLoad(cell.SceneGuid);
+    const auto duplicateRequest = world.RequestLoad(cell.SceneGuid);
+    Expect(duplicateRequest == request, "duplicate asynchronous scene requests are coalesced");
+    Expect(world.CancelLoad(request), "pending asynchronous load cancels");
+    TickUntilSettled(world, request);
+    Expect(world.GetLoadStatus(request)->State == MetaCoreSceneLoadState::Cancelled, "cancelled request remains cancelled");
+}
+
+void TestSceneDependencyValidation() {
+    auto root = MakeScene("DependencyRoot");
+    auto child = MakeScene("DependencyChild");
+    root.SubScenes.push_back({child.SceneGuid});
+    child.SubScenes.push_back({root.SceneGuid});
+    std::unordered_map<MetaCoreAssetGuid, MetaCoreSceneDocument, MetaCoreAssetGuidHasher> documents{
+        {root.SceneGuid, root}, {child.SceneGuid, child}
+    };
+    MetaCoreSceneWorld world([&](const MetaCoreAssetGuid& guid) -> std::optional<MetaCoreSceneDocument> {
+        const auto iterator = documents.find(guid);
+        return iterator == documents.end() ? std::nullopt : std::optional(iterator->second);
+    });
+    const auto issues = world.ValidateDependencies(root);
+    Expect(std::any_of(issues.begin(), issues.end(), [](const std::string& issue) {
+        return issue.find("cycle") != std::string::npos;
+    }), "recursive SubScene cycle is rejected");
+}
+
+void TestPrefabVariantNestedAndOverrides() {
+    MetaCorePrefabDocument base;
+    base.PrefabGuid = MetaCoreAssetGuid::Generate();
+    base.Name = "Base";
+    MetaCoreGameObjectData root;
+    root.Id = 1;
+    root.StableObjectGuid = MetaCoreBuildDeterministicGuid(base.PrefabGuid, 1);
+    root.Name = "BaseRoot";
+    base.GameObjects.push_back(root);
+
+    MetaCorePrefabDocument nested;
+    nested.PrefabGuid = MetaCoreAssetGuid::Generate();
+    nested.Name = "Nested";
+    MetaCoreGameObjectData nestedRoot;
+    nestedRoot.Id = 1;
+    nestedRoot.StableObjectGuid = MetaCoreBuildDeterministicGuid(nested.PrefabGuid, 1);
+    nestedRoot.Name = "NestedRoot";
+    nested.GameObjects.push_back(nestedRoot);
+
+    MetaCorePrefabDocument variant;
+    variant.PrefabGuid = MetaCoreAssetGuid::Generate();
+    variant.BasePrefabGuid = base.PrefabGuid;
+    variant.Name = "Variant";
+    variant.Overrides.push_back({
+        root.StableObjectGuid, "Transform", "Position", MetaCorePrefabOverrideOperation::SetProperty, "[1,2,3]"
+    });
+    MetaCoreNestedPrefabDocument nestedInstance;
+    nestedInstance.MountNodeGuid = root.StableObjectGuid;
+    nestedInstance.PrefabAssetGuid = nested.PrefabGuid;
+    nestedInstance.InstanceGuid = MetaCoreAssetGuid::Generate();
+    variant.NestedPrefabs.push_back(nestedInstance);
+
+    std::unordered_map<MetaCoreAssetGuid, MetaCorePrefabDocument, MetaCoreAssetGuidHasher> prefabs{
+        {base.PrefabGuid, base}, {nested.PrefabGuid, nested}, {variant.PrefabGuid, variant}
+    };
+    MetaCorePrefabResolver resolver([&](const MetaCoreAssetGuid& guid) -> std::optional<MetaCorePrefabDocument> {
+        const auto iterator = prefabs.find(guid);
+        return iterator == prefabs.end() ? std::nullopt : std::optional(iterator->second);
+    });
+
+    const auto resolved = resolver.Resolve(variant.PrefabGuid);
+    Expect(resolved && resolved->Document.GameObjects.size() == 2, "variant resolves base and nested prefab");
+    Expect(resolved->Document.GameObjects[0].Transform.Position == glm::vec3(1.0F, 2.0F, 3.0F), "variant property override");
+    Expect(resolved->Document.GameObjects[1].ParentId == resolved->Document.GameObjects[0].Id, "nested prefab mounts below target node");
+
+    const auto instanceGuid = MetaCoreAssetGuid::Generate();
+    const auto firstInstance = resolver.Instantiate(variant.PrefabGuid, instanceGuid);
+    const auto secondInstance = resolver.Instantiate(variant.PrefabGuid, instanceGuid);
+    Expect(firstInstance && secondInstance && firstInstance->size() == secondInstance->size(), "prefab instantiate succeeds");
+    for (std::size_t index = 0; index < firstInstance->size(); ++index)
+        Expect((*firstInstance)[index].StableObjectGuid == (*secondInstance)[index].StableObjectGuid,
+            "same instance GUID yields stable prefab object GUIDs");
+
+    const std::vector<MetaCorePrefabOverrideDocument> structuralOverrides{
+        {root.StableObjectGuid, "Camera", "", MetaCorePrefabOverrideOperation::AddComponent, "{}"},
+        {root.StableObjectGuid, "", "", MetaCorePrefabOverrideOperation::AddChild,
+            R"({"Name":"InstanceChild","Position":[4,5,6]})"}
+    };
+    const auto structuralInstance = resolver.Instantiate(
+        variant.PrefabGuid, MetaCoreAssetGuid::Generate(), structuralOverrides
+    );
+    Expect(structuralInstance && structuralInstance->size() == 3,
+        "instance structural override adds a child");
+    Expect((*structuralInstance)[0].Camera.has_value(), "instance component override adds a component");
+
+    prefabs[base.PrefabGuid].BasePrefabGuid = variant.PrefabGuid;
+    Expect(!resolver.Resolve(variant.PrefabGuid), "prefab inheritance cycle rejected");
+}
+
+}  // namespace
+
+int main() {
+    TestSceneJsonAndPackageVersions();
+    TestAdditiveWorldAndQualifiedReferences();
+    TestAsynchronousLoadCancelAndStreaming();
+    TestSceneDependencyValidation();
+    TestPrefabVariantNestedAndOverrides();
+    std::cout << "MetaCoreSceneTests passed\n";
+    return 0;
+}
diff --git a/tests/MetaCoreSmokeTests.cpp b/tests/MetaCoreSmokeTests.cpp
index f9c756a..acbc0c3 100644
--- a/tests/MetaCoreSmokeTests.cpp
+++ b/tests/MetaCoreSmokeTests.cpp
@@ -25,6 +25,7 @@
 #include "MetaCoreScene/MetaCoreTransformUtils.h"
 #include "MetaCoreFoundation/MetaCoreHash.h"
 #include "../Source/MetaCoreEditor/Private/MetaCoreGltfImporter.h"
+#include "../Source/MetaCoreEditor/Private/MetaCoreEditorCameraController.h"
 #include <nlohmann/json.hpp>
 
 #include <cstdlib>
@@ -1429,6 +1430,10 @@ void MetaCoreTestSceneRenderSyncBuildsRenderableCameraLightSnapshot() {
     for (const auto& renderable : snapshot.Renderables) {
         if (renderable.ObjectId == root.GetId()) {
             MetaCoreExpect(renderable.Visible == true, "RenderSync 根对象 Visible 应为 true");
+            MetaCoreExpect(
+                MetaCore::MetaCoreUsesNativeGltfVisibility(renderable),
+                "导入 glTF 应跳过 ECS 单位代理包围盒，交由 gltfio 使用真实几何包围盒剔除"
+            );
             MetaCoreExpectVec3Near(renderable.BaseColor, glm::vec3(0.5F, 0.6F, 0.7F), "RenderSync 根对象 BaseColor 应正确");
             MetaCoreExpect(std::abs(renderable.Metallic - 0.35F) < 0.0001F, "RenderSync 根对象 Metallic 应正确");
             MetaCoreExpect(std::abs(renderable.Roughness - 0.45F) < 0.0001F, "RenderSync 根对象 Roughness 应正确");
@@ -1442,6 +1447,10 @@ void MetaCoreTestSceneRenderSyncBuildsRenderableCameraLightSnapshot() {
             MetaCoreExpect(renderable.EmissiveTexturePath == "Assets/Textures/SyncEmissive.png", "RenderSync 根对象自发光贴图路径应正确");
             MetaCoreExpect(renderable.AoTexturePath == "Assets/Textures/SyncAo.png", "RenderSync 根对象 AO 贴图路径应正确");
         } else if (renderable.ObjectId == child.GetId()) {
+            MetaCoreExpect(
+                !MetaCore::MetaCoreUsesNativeGltfVisibility(renderable),
+                "普通内置网格仍应使用引擎可见性系统"
+            );
             MetaCoreExpect(renderable.Visible == false, "RenderSync 子对象 Visible 应为 false");
             MetaCoreExpectVec3Near(renderable.BaseColor, glm::vec3(0.1F, 0.2F, 0.3F), "RenderSync 子对象 BaseColor 应正确");
         }
@@ -1770,8 +1779,8 @@ void MetaCoreTestViewportPickingUsesMeshTrianglesBeforeHierarchyDepth() {
     shellMesh.IndexCount = 6;
     shellMesh.PayloadIndex = 1;
     shellMesh.PayloadSize = makePlanePayload(2.0F).size();
-    shellMesh.BoundingBoxMin = glm::vec3(-2.0F, -2.0F, 0.0F);
-    shellMesh.BoundingBoxMax = glm::vec3(2.0F, 2.0F, 0.0F);
+    shellMesh.BoundingBoxMin = glm::vec3(-2000.0F, -100.0F, -1000.0F);
+    shellMesh.BoundingBoxMax = glm::vec3(2000.0F, 100.0F, 1000.0F);
     document.GeneratedMeshAssets.push_back(shellMesh);
 
     MetaCore::MetaCoreMeshAssetDocument interiorMesh;
@@ -1841,6 +1850,12 @@ void MetaCoreTestViewportPickingUsesMeshTrianglesBeforeHierarchyDepth() {
     );
 
     MetaCoreExpect(pickedObjectId == shellObject.GetId(), "三角面拾取应选择可见的外壳，而不是层级更深的内部部件");
+    editorContext.SetSelectedObjectId(shellObject.GetId());
+    interactionService.FocusSelectedObject(editorContext);
+    const auto focusedView = editorContext.GetCameraController().BuildSceneView();
+    const float focusedDistance = glm::length(focusedView.CameraPosition - focusedView.CameraTarget);
+    MetaCoreExpect(focusedDistance > 5000.0F, "模型聚焦应采用资源真实包围盒，而不是根节点单位 Scale");
+    MetaCoreExpect(focusedView.FarClip > focusedDistance + 2000.0F, "模型聚焦应扩展 Far Clip 覆盖完整资源包围盒");
 
     coreServicesModule->Shutdown(moduleRegistry);
     moduleRegistry.ShutdownServices();
@@ -5493,6 +5508,16 @@ void MetaCoreTestParticleRenderableGrowthAndRemoval() {
 
 }  // namespace
 
+void MetaCoreTestLargeBoundsEditorCameraFraming() {
+    MetaCore::MetaCoreEditorCameraController camera;
+    camera.FocusBounds(glm::vec3(625.0F, -510.0F, 46.0F), 1600.0F);
+    const MetaCore::MetaCoreSceneView view = camera.BuildSceneView();
+    const float distance = glm::length(view.CameraPosition - view.CameraTarget);
+    MetaCoreExpect(distance > 5000.0F, "大模型聚焦距离不应被 100 单位上限截断");
+    MetaCoreExpect(view.FarClip > distance + 1600.0F, "大模型应完整位于动态 Far Clip 内");
+    MetaCoreExpect(view.NearClip >= 0.01F && view.NearClip <= 1.0F, "动态 Near Clip 应保持有效范围");
+}
+
 int main() {
     std::setvbuf(stdout, nullptr, _IONBF, 0);
     std::setvbuf(stderr, nullptr, _IONBF, 0);
@@ -5587,6 +5612,8 @@ int main() {
     MetaCoreTestCameraComponentJsonRoundTripAndLegacyDefaults();
     std::cout << "[RUN] MetaCoreTestCameraSelectionAndProjectionUtilities..." << std::endl;
     MetaCoreTestCameraSelectionAndProjectionUtilities();
+    std::cout << "[RUN] MetaCoreTestLargeBoundsEditorCameraFraming..." << std::endl;
+    MetaCoreTestLargeBoundsEditorCameraFraming();
     std::cout << "[RUN] MetaCoreTestViewportPickingPrefersModelChildNode..." << std::endl;
     MetaCoreTestViewportPickingPrefersModelChildNode();
     std::cout << "[RUN] MetaCoreTestViewportPickingUsesMeshTrianglesBeforeHierarchyDepth..." << std::endl;