diff --git a/UnitTests/CoordinateSystem/HostCoordinateAdapterTests.cs b/UnitTests/CoordinateSystem/HostCoordinateAdapterTests.cs
index a5d7931..84496f3 100644
--- a/UnitTests/CoordinateSystem/HostCoordinateAdapterTests.cs
+++ b/UnitTests/CoordinateSystem/HostCoordinateAdapterTests.cs
@@ -213,25 +213,27 @@ namespace NavisworksTransport.UnitTests.CoordinateSystem
         }
 
         [TestMethod]
-        public void ZUp_HostRotationCorrection_ShouldKeepHostZAxisInvariantInHostSpace()
+        public void ZUp_HostRotationCorrection_YDegrees_ShouldKeepHostZAxisInvariant()
         {
+            // ZUp 下 YDegrees = up 轴(=Z)。绕 Z 转，Z 轴自身不变。
             var adapter = new HostCoordinateAdapter(CoordinateSystemType.ZUp);
             Quaternion hostCorrection = adapter.CreateHostRotationCorrection(
-                new LocalEulerRotationCorrection(0.0, 0.0, 90.0));
+                new LocalEulerRotationCorrection(0.0, 90.0, 0.0));
 
             Vector3 rotatedUp = Vector3.Transform(Vector3.UnitZ, hostCorrection);
             AssertVector(rotatedUp, 0.0, 0.0, 1.0);
         }
 
         [TestMethod]
-        public void ZUp_ComposeHostQuaternion_ShouldApplyHostZCorrectionAfterBaseline()
+        public void ZUp_ComposeHostQuaternion_YDegrees_ShouldApplyHostZAxisRotation()
         {
+            // ZUp 下 YDegrees = up 轴(=Z)。绕 Z 转 90°：X→Y, Y→-X, Z 不变。
             var adapter = new HostCoordinateAdapter(CoordinateSystemType.ZUp);
             var baseline = Quaternion.Identity;
 
             Quaternion composed = adapter.ComposeHostQuaternion(
                 baseline,
-                new LocalEulerRotationCorrection(0.0, 0.0, 90.0));
+                new LocalEulerRotationCorrection(0.0, 90.0, 0.0));
 
             Matrix4x4 linear = Matrix4x4.CreateFromQuaternion(composed);
 
diff --git a/UnitTests/CoordinateSystem/RotatedObjectExtentHelperTests.cs b/UnitTests/CoordinateSystem/RotatedObjectExtentHelperTests.cs
index ca93b9b..42e15b2 100644
--- a/UnitTests/CoordinateSystem/RotatedObjectExtentHelperTests.cs
+++ b/UnitTests/CoordinateSystem/RotatedObjectExtentHelperTests.cs
@@ -49,12 +49,14 @@ namespace NavisworksTransport.UnitTests.CoordinateSystem
         }
 
         [TestMethod]
-        public void ZUp_HostY90_ShouldPromoteForwardSizeToUpExtent()
+        public void ZUp_HostZDegrees_ShouldPromoteForwardSizeToUpExtent()
         {
+            // ZUp 下 ZDegrees = non-up 轴(=Y)。绕 Y 转 90°：X(forward)→-Z(up), Z(up)→X。
+            // forward(6) 提升到 up，up(2) 降到 forward。
             var adapter = new HostCoordinateAdapter(CoordinateSystemType.ZUp);
             var convention = ModelAxisConvention.CreateDefaultForHost(CoordinateSystemType.ZUp);
             Quaternion correction = adapter.CreateCanonicalRotationCorrection(
-                new LocalEulerRotationCorrection(0.0, 90.0, 0.0));
+                new LocalEulerRotationCorrection(0.0, 0.0, 90.0));
 
             var result = RotatedObjectExtentHelper.CalculateProjectedSemanticExtents(
                 convention,
@@ -69,12 +71,14 @@ namespace NavisworksTransport.UnitTests.CoordinateSystem
         }
 
         [TestMethod]
-        public void ZUp_HostZ90_ShouldKeepUpExtentUnchanged()
+        public void ZUp_HostYDegrees_ShouldKeepUpExtentUnchanged()
         {
+            // ZUp 下 YDegrees = up 轴(=Z)。绕 Z 转 90°：X→Y, Y→-X, Z(up) 不变。
+            // forward 和 side 互换，up 不变。
             var adapter = new HostCoordinateAdapter(CoordinateSystemType.ZUp);
             var convention = ModelAxisConvention.CreateDefaultForHost(CoordinateSystemType.ZUp);
             Quaternion correction = adapter.CreateCanonicalRotationCorrection(
-                new LocalEulerRotationCorrection(0.0, 0.0, 90.0));
+                new LocalEulerRotationCorrection(0.0, 90.0, 0.0));
 
             var result = RotatedObjectExtentHelper.CalculateProjectedSemanticExtents(
                 convention,
diff --git a/src/Utils/CoordinateSystem/ObjectPassageProjectionOptimizer.cs b/src/Utils/CoordinateSystem/ObjectPassageProjectionOptimizer.cs
index aaba055..29acaee 100644
--- a/src/Utils/CoordinateSystem/ObjectPassageProjectionOptimizer.cs
+++ b/src/Utils/CoordinateSystem/ObjectPassageProjectionOptimizer.cs
@@ -157,7 +157,9 @@ namespace NavisworksTransport.Utils.CoordinateSystem
             }
 
             LocalEulerRotationCorrection bestCorrection = LocalEulerRotationCorrection.Zero;
-            ObjectPassageProjectionScore bestScore = ObjectPassageProjectionScore.Invalid;
+            // 必须评估 correction=Zero 作为初始候选：当 baseline 已对齐路径时，
+            // Zero 就是最优解；若不评估，随机采样必然替换它，refine 也收敛不回 0。
+            ObjectPassageProjectionScore bestScore = evaluator(bestCorrection);
             Quaternion bestQuaternion = Quaternion.Identity;
 
             // S³ 均匀采样四元数 → 转 Euler → 覆盖 SO(3) 无万向节死锁