generate unique names for nodes in 3d models

Assets/Scripts/Commands/BreakModelApartCommand.cs

@@ -14,6 +14,7 @@
 
 using System.Collections.Generic;
 using System.Linq;
+using System.Text;
 using UnityEngine;
 
 namespace TiltBrush
@@ -167,13 +168,16 @@ public BreakModelApartCommand(ModelWidget initialWidget, BaseCommand parent = nu
 
         private static string GetHierarchyPath(Transform root, Transform obj)
         {
-            string path = "/" + obj.name;
+            StringBuilder stringBuilder = new StringBuilder();
+            stringBuilder.Insert(0, "/" + obj.name);
+
             while (obj.transform.parent != root)
             {
                 obj = obj.transform.parent;
-                path = "/" + obj.name + path;
+                stringBuilder.Insert(0, "/" + obj.name);
             }
-            return path;
+
+            return stringBuilder.ToString();
         }
 
         protected override void OnRedo()

Assets/Scripts/Model.cs

@@ -21,6 +21,7 @@
 using System.Linq;
 using System.Threading.Tasks;
 using TiltBrushToolkit;
+using Unity.Profiling;
 using Unity.VectorGraphics;
 using Debug = UnityEngine.Debug;
 using UObject = UnityEngine.Object;
@@ -857,11 +858,44 @@ public void EndCreatePrefab(GameObject go, List<string> warnings)
             }
             m_ModelParent = go.transform;
 
+#if DEVELOPMENT_BUILD || UNITY_EDITOR
+            ProfilerMarker generateUniqueNamesPerfMarker = new ProfilerMarker("Model.GenerateUniqueNames");
+            generateUniqueNamesPerfMarker.Begin();
+#endif
+
+            GenerateUniqueNames(m_ModelParent);
+
+#if DEVELOPMENT_BUILD || UNITY_EDITOR
+            generateUniqueNamesPerfMarker.End();
+#endif
+
             // !!! Add to material dictionary here?
 
             m_Valid = true;
             DisplayWarnings(warnings);
+        }
+
+
+        // This method is called when the model has been loaded and the node tree is available
+        // This method is necessary because (1) nodes in e.g glTF files don't need to have unique names
+        // and (2) there's code in at least ModelWidget that searches for specific nodes using node names
+        private static void GenerateUniqueNames(Transform rootNode)
+        {
+            void SetUniqueNameForNode(Transform node)
+            {
+                // GetInstanceID returns a unique ID for every GameObject during a runtime session
+                node.name += " uid: " + node.gameObject.GetInstanceID();
+
+                foreach (Transform child in node)
+                {
+                    SetUniqueNameForNode(child);
+                }
+            }
 
+            foreach (Transform child in rootNode)
+            {
+                SetUniqueNameForNode(child);
+            }
         }
 
         public void UnloadModel()

Assets/Scripts/Widgets/ModelWidget.cs

@@ -13,6 +13,7 @@
 // limitations under the License.
 
 using System;
+using System.Collections.Generic;
 using UnityEngine;
 using System.Linq;
 using System.Threading.Tasks;
@@ -29,6 +30,18 @@ public class ModelWidget : MediaWidget
         [SerializeField] private float m_MaxBloat;
 
         private Model m_Model;
+
+
+        // What is Subtree?
+        // e.g. if we have 3d model with 3 chairs with the hierarchy below,
+        // then when the model is broken apart, we create a separate ModelWidget for each Chair1,Chair2,Chair3
+        // e.g for Chair1, Subtree = "Root/Chair1"
+        /*
+         Root (empty node) 
+            Chair1 (mesh)
+            Chair2 (mesh)
+            Chair3 (mesh)
+         */
         private string m_Subtree;
         public string Subtree
         {
@@ -322,6 +335,9 @@ public bool HasSubModels()
             return false;
         }
 
+        // Update the transform hierarchy of this ModelWidget to only contain m_Subtree
+        // e.g if Subtree = "CarBody/Floor/Wheel1", then this method will update the transform hierarchy to contain nodes
+        // starting at CarBody/Floor/Wheel1
         public void SyncHierarchyToSubtree(string previousSubtree = null)
         {
             if (string.IsNullOrEmpty(Subtree)) return;
@@ -355,9 +371,9 @@ public void SyncHierarchyToSubtree(string previousSubtree = null)
             bool excludeChildren = false;
             if (subpathToTraverse.EndsWith(".mesh"))
             {
-                subpathToTraverse = subpathToTraverse.Substring(0, subpathToTraverse.Length - 5);
+                subpathToTraverse = subpathToTraverse.Substring(0, subpathToTraverse.Length - ".mesh".Length);
                 excludeChildren = true;
-            }
+            } 
             if (node.name == subpathToTraverse)
             {
                 // We're already at the right node
@@ -366,7 +382,7 @@ public void SyncHierarchyToSubtree(string previousSubtree = null)
             }
             else
             {
-                // node will be null if not found
+                // - node will be null if not found
                 node = node.Find(subpathToTraverse);
             }