Fix for wrong "this"

src/Collisions/babylon.collisionWorker.js

@@ -162,6 +162,7 @@ var BABYLON;
             postMessage(reply, undefined);
         };
         CollisionDetectorTransferable.prototype.onUpdate = function (payload) {
+            var _this = this;
             var replay = {
                 error: BABYLON.WorkerReplyType.SUCCESS,
                 taskType: BABYLON.WorkerTaskType.UPDATE
@@ -178,10 +179,10 @@ var BABYLON;
                     }
                 }
                 payload.removedGeometries.forEach(function (id) {
-                    this._collisionCache.removeGeometry(id);
+                    _this._collisionCache.removeGeometry(id);
                 });
                 payload.removedMeshes.forEach(function (uniqueId) {
-                    this._collisionCache.removeMesh(uniqueId);
+                    _this._collisionCache.removeMesh(uniqueId);
                 });
             }
             catch (x) {

src/Collisions/babylon.collisionWorker.ts

@@ -217,11 +217,11 @@ module BABYLON {
 					}
 				}
 				
-				payload.removedGeometries.forEach(function(id) {
+				payload.removedGeometries.forEach((id) => {
 					this._collisionCache.removeGeometry(id);
 				});
 				
-				payload.removedMeshes.forEach(function(uniqueId) {
+				payload.removedMeshes.forEach((uniqueId) => {
 					this._collisionCache.removeMesh(uniqueId);
 				});