diff --git a/source/engine/main.js b/source/engine/main.js
index 91a6deb..87404b7 100644
--- a/source/engine/main.js
+++ b/source/engine/main.js
@@ -66,7 +66,7 @@ import { Unit } from './model/unit.js';
 import { ParameterListBuilder, ParameterListParser, CreateUrlBuilder, CreateUrlParser, CreateModelUrlParameters, ParameterConverter } from './parameters/parameterlist.js';
 import { ModelToThreeConversionParams, ModelToThreeConversionOutput, ThreeConversionStateHandler, ThreeNodeTree, ThreeMaterialHandler, ThreeMeshMaterialHandler, ConvertModelToThreeObject, MaterialGeometryType } from './threejs/threeconverter.js';
 import { ThreeModelLoader } from './threejs/threemodelloader.js';
-import { ThreeColorConverter, ThreeLinearToSRGBColorConverter, ThreeSRGBToLinearColorConverter, HasHighpDriverIssue, GetShadingType, ConvertThreeColorToColor, ConvertColorToThreeColor, ConvertThreeGeometryToMesh, CreateHighlightMaterial, CreateHighlightMaterials, DisposeThreeObjects, ShadingType } from './threejs/threeutils.js';
+import { ThreeColorConverter, ThreeLinearToSRGBColorConverter, ThreeSRGBToLinearColorConverter, HasHighpDriverIssue, GetShadingType, ConvertThreeColorToColor, ConvertColorToThreeColor, ConvertThreeGeometryToMesh, CreateHighlightMaterial, CreateHighlightMaterials, DisposeThreeObjects, GetLineSegmentsProjectedDistance, ShadingType } from './threejs/threeutils.js';
 import { Camera, CameraIsEqual3D, NavigationMode, ProjectionMode } from './viewer/camera.js';
 import { GetIntegerFromStyle, GetDomElementExternalWidth, GetDomElementExternalHeight, GetDomElementInnerDimensions, GetDomElementClientCoordinates, CreateDomElement, AddDomElement, AddDiv, ClearDomElement, InsertDomElementBefore, InsertDomElementAfter, ShowDomElement, IsDomElementVisible, SetDomElementWidth, SetDomElementHeight, GetDomElementOuterWidth, GetDomElementOuterHeight, SetDomElementOuterWidth, SetDomElementOuterHeight, CreateDiv } from './viewer/domutils.js';
 import { EmbeddedViewer, Init3DViewerFromUrlList, Init3DViewerFromFileList, Init3DViewerElements } from './viewer/embeddedviewer.js';
@@ -305,6 +305,7 @@ export {
     CreateHighlightMaterial,
     CreateHighlightMaterials,
     DisposeThreeObjects,
+    GetLineSegmentsProjectedDistance,
     ShadingType,
     Camera,
     CameraIsEqual3D,
diff --git a/source/engine/threejs/threeutils.js b/source/engine/threejs/threeutils.js
index 132373b..7e54f34 100644
--- a/source/engine/threejs/threeutils.js
+++ b/source/engine/threejs/threeutils.js
@@ -1,5 +1,6 @@
 import { Coord2D } from '../geometry/coord2d.js';
 import { Coord3D } from '../geometry/coord3d.js';
+import { Segment2D, SegmentPointDistance2D } from '../geometry/line2d.js';
 import { RGBColorFromFloatComponents } from '../model/color.js';
 import { MaterialType } from '../model/material.js';
 import { Mesh } from '../model/mesh.js';
@@ -272,3 +273,33 @@ export function DisposeThreeObjects (mainObject)
         }
     });
 }
+
+export function GetLineSegmentsProjectedDistance (camera, canvasWidth, canvasHeight, lineSegments, screenPoint)
+{
+    function GetProjectedVertex (camera, canvasWidth, canvasHeight, lineSegments, vertices, index)
+    {
+        let vertex = new THREE.Vector3 (
+            vertices[3 * index],
+            vertices[3 * index + 1],
+            vertices[3 * index + 2]
+        );
+        vertex.applyMatrix4 (lineSegments.matrixWorld);
+        let projected = vertex.project (camera);
+        return new Coord2D (
+            (projected.x + 1.0) * canvasWidth / 2.0,
+            -(projected.y - 1.0) * canvasHeight / 2.0
+        );
+    }
+
+    let vertices = lineSegments.geometry.attributes.position.array;
+    let segmentCount = vertices.length / 6;
+    let distance = Infinity;
+    for (let segmentIndex = 0; segmentIndex < segmentCount; segmentIndex++) {
+        let segment = new Segment2D (
+            GetProjectedVertex (camera, canvasWidth, canvasHeight, lineSegments, vertices, 2 * segmentIndex),
+            GetProjectedVertex (camera, canvasWidth, canvasHeight, lineSegments, vertices, 2 * segmentIndex + 1)
+        );
+        distance = Math.min (distance, SegmentPointDistance2D (segment, screenPoint));
+    }
+    return distance;
+}
diff --git a/source/engine/viewer/viewermodel.js b/source/engine/viewer/viewermodel.js
index 0e128c5..c210af3 100644
--- a/source/engine/viewer/viewermodel.js
+++ b/source/engine/viewer/viewermodel.js
@@ -1,8 +1,10 @@
 import { RGBColor } from '../model/color.js';
-import { ConvertColorToThreeColor, DisposeThreeObjects } from '../threejs/threeutils.js';
+import { ConvertColorToThreeColor, DisposeThreeObjects, GetLineSegmentsProjectedDistance } from '../threejs/threeutils.js';
 
 import * as THREE from 'three';
 
+const LineThresholdInPixels = 10.0;
+
 export const IntersectionMode =
 {
 	MeshOnly : 1,
@@ -127,7 +129,6 @@ export class ViewerMainModel
         this.edgeSettings = new EdgeSettings (false, new RGBColor (0, 0, 0), 1);
         this.hasLines = false;
         this.hasPolygonOffset = false;
-        this.fullBoundingBox = null;
     }
 
     SetMainObject (mainObject)
@@ -135,7 +136,6 @@ export class ViewerMainModel
         this.mainModel.SetRootObject (mainObject);
         this.hasLines = false;
         this.hasPolygonOffset = false;
-        this.fullBoundingBox = null;
 
         this.EnumerateLines ((line) => {
             this.hasLines = true;
@@ -200,17 +200,6 @@ export class ViewerMainModel
         this.UpdatePolygonOffset ();
     }
 
-    GetFullBoundingBox ()
-    {
-        if (this.fullBoundingBox !== null) {
-            return this.fullBoundingBox;
-        }
-        this.fullBoundingBox = this.GetBoundingBox (() => {
-            return true;
-        });
-        return this.fullBoundingBox;
-    }
-
     GetBoundingBox (needToProcess)
     {
         let hasMesh = false;
@@ -311,18 +300,6 @@ export class ViewerMainModel
 
     GetMeshIntersectionUnderMouse (intersectionMode, mouseCoords, camera, width, height)
     {
-        function CalculateLineThreshold (mousePos, camera, boundingBoxCenter)
-        {
-            let thresholdInScreenCoordinates = 15.0;
-            let frustumRange = camera.far - camera.near;
-            let cameraDistanceFromCenter = boundingBoxCenter.distanceTo (camera.position);
-            let distanceInFrustumRatio = cameraDistanceFromCenter / frustumRange;
-            let zValue = -1.0 + 2.0 * distanceInFrustumRatio;
-            let referencePoint1 = new THREE.Vector3 (mousePos.x, mousePos.y, zValue).unproject (camera);
-            let referencePoint2 = new THREE.Vector3 (mousePos.x + thresholdInScreenCoordinates, mousePos.y, zValue).unproject (camera);
-            return referencePoint1.distanceTo (referencePoint2);
-        }
-
         if (this.mainModel.IsEmpty ()) {
             return null;
         }
@@ -336,16 +313,9 @@ export class ViewerMainModel
         mousePos.y = -(mouseCoords.y / height) * 2 + 1;
 
         let raycaster = new THREE.Raycaster ();
-        if (this.hasLines) {
-            let boundingBox = this.GetFullBoundingBox ();
-            if (boundingBox !== null) {
-                let boundingBoxCenter = new THREE.Vector3 (0.0, 0.0, 0.0);
-                boundingBox.getCenter (boundingBoxCenter);
-                raycaster.params.Line.threshold = CalculateLineThreshold (mousePos, camera, boundingBoxCenter);
-            }
-        }
-
         raycaster.setFromCamera (mousePos, camera);
+        raycaster.params.Line.threshold = 10.0;
+
         let iSectObjects = raycaster.intersectObject (this.mainModel.GetRootObject (), true);
         for (let i = 0; i < iSectObjects.length; i++) {
             let iSectObject = iSectObjects[i];
@@ -355,7 +325,13 @@ export class ViewerMainModel
             if (intersectionMode === IntersectionMode.MeshOnly && iSectObject.object.isLineSegments) {
                 continue;
             }
-            if (iSectObject.object.isMesh || iSectObject.object.isLineSegments) {
+            if (iSectObject.object.isMesh) {
+                return iSectObject;
+            } else if (iSectObject.object.isLineSegments) {
+                let distance = GetLineSegmentsProjectedDistance (camera, width, height, iSectObject.object, mouseCoords);
+                if (distance > LineThresholdInPixels) {
+                    continue;
+                }
                 return iSectObject;
             }
         }