Add HotFix, didn't stick the first time

Assets/SceneUnderstanding/Core/Understanding/Scripts/SceneUnderstandingManager.cs

@@ -171,7 +171,7 @@ namespace Microsoft.MixedReality.SceneUnderstanding.Samples.Unity
 
         private async void Start()
         {
-            SceneRoot = SceneRoot == null ? new GameObject("Root") : SceneRoot;
+            SceneRoot = SceneRoot == null ? new GameObject("Scene Root") : SceneRoot;
 
             // Considering that device is currently not supported in the editor means that
             // if the application is running in the editor it is for sure running on PC and
@@ -192,14 +192,14 @@ namespace Microsoft.MixedReality.SceneUnderstanding.Samples.Unity
 
                 if (!SceneUnderstanding.SceneObserver.IsSupported())
                 {
-                    Debug.LogError("SceneUnderstandingDataProvider.Start: Scene Understanding not supported.");
+                    Debug.LogError("SceneUnderstandingManager.Start: Scene Understanding not supported.");
                     return;
                 }
 
                 SceneObserverAccessStatus access = await SceneUnderstanding.SceneObserver.RequestAccessAsync();
                 if (access != SceneObserverAccessStatus.Allowed)
                 {
-                    Debug.LogError("SceneUnderstandingDataProvider.Start: Access to Scene Understanding has been denied.\n" +
+                    Debug.LogError("SceneUnderstandingManager.Start: Access to Scene Understanding has been denied.\n" +
                                    "Reason: " + access);
                     return;
                 }
@@ -323,7 +323,7 @@ namespace Microsoft.MixedReality.SceneUnderstanding.Samples.Unity
         /// <param name="lod">If world mesh is enabled, lod controls the resolution of the mesh returned.</param>
         private void RetrieveData(float boundingSphereRadiusInMeters, bool enableQuads, bool enableMeshes, bool enableInference, bool enableWorldMesh, SceneUnderstanding.SceneMeshLevelOfDetail lod)
         {
-            Debug.Log("SceneUnderstandingDataProvider.RetrieveData: Started.");
+            Debug.Log("SceneUnderstandingManager.RetrieveData: Started.");
 
             System.Diagnostics.Stopwatch stopwatch = new System.Diagnostics.Stopwatch();
             stopwatch.Start();
@@ -473,21 +473,21 @@ namespace Microsoft.MixedReality.SceneUnderstanding.Samples.Unity
 
             if (suScene != null)
             {
-                // If there was previously a scene displayed in the game world, destroy it
-                // to avoid overlap with the new scene about to be displayed
-                DestroyAllGameObjectsUnderParent(SceneRoot.transform);
-
-                // Allow from one frame to yield the coroutine back to the main thread
-                yield return null;
-
                 // Retrieve a transformation matrix that will allow us orient the Scene Understanding Objects into
                 // their correct corresponding position in the unity world
-                System.Numerics.Matrix4x4 sceneToUnityTransformAsMatrix4x4 = GetSceneToUnityTransformAsMatrix4x4(suScene);
+                System.Numerics.Matrix4x4? sceneToUnityTransformAsMatrix4x4 = GetSceneToUnityTransformAsMatrix4x4(suScene);
 
                 if (sceneToUnityTransformAsMatrix4x4 != null)
                 {
+                    // If there was previously a scene displayed in the game world, destroy it
+                    // to avoid overlap with the new scene about to be displayed
+                    DestroyAllGameObjectsUnderParent(SceneRoot.transform);
+
+                    // Allow from one frame to yield the coroutine back to the main thread
+                    yield return null;
+
                     // Using the transformation matrix generated above, port its values into the tranform of the scene root (Numerics.matrix -> GameObject.Transform)
-                    SetUnityTransformFromMatrix4x4(SceneRoot.transform, sceneToUnityTransformAsMatrix4x4, RunOnDevice);
+                    SetUnityTransformFromMatrix4x4(SceneRoot.transform, sceneToUnityTransformAsMatrix4x4.Value, RunOnDevice);
 
                     if (!RunOnDevice)
                     {
@@ -1064,7 +1064,7 @@ namespace Microsoft.MixedReality.SceneUnderstanding.Samples.Unity
         /// from the Scene Understanding Coordinate System to the Unity one
         /// </summary>
         /// <param name="scene"> Scene from which to get the Scene Understanding Coordinate System </param>
-        private System.Numerics.Matrix4x4 GetSceneToUnityTransformAsMatrix4x4(SceneUnderstanding.Scene scene)
+        private System.Numerics.Matrix4x4? GetSceneToUnityTransformAsMatrix4x4(SceneUnderstanding.Scene scene)
         {
             System.Numerics.Matrix4x4? sceneToUnityTransform = System.Numerics.Matrix4x4.Identity;
 
@@ -1086,7 +1086,7 @@ namespace Microsoft.MixedReality.SceneUnderstanding.Samples.Unity
                 }
             }
 
-            return sceneToUnityTransform.Value;
+            return sceneToUnityTransform;
         }
 
         /// <summary>
@@ -1245,11 +1245,11 @@ namespace Microsoft.MixedReality.SceneUnderstanding.Samples.Unity
 
                 if (suScene != null)
                 {
-                    System.Numerics.Matrix4x4 sceneToUnityTransformAsMatrix4x4 = GetSceneToUnityTransformAsMatrix4x4(suScene);
+                    System.Numerics.Matrix4x4? sceneToUnityTransformAsMatrix4x4 = GetSceneToUnityTransformAsMatrix4x4(suScene);
 
                     if (sceneToUnityTransformAsMatrix4x4 != null)
                     {
-                        SetUnityTransformFromMatrix4x4(SceneRoot.transform, sceneToUnityTransformAsMatrix4x4, RunOnDevice);
+                        SetUnityTransformFromMatrix4x4(SceneRoot.transform, sceneToUnityTransformAsMatrix4x4.Value, RunOnDevice);
 
                         if (!RunOnDevice)
                         {