[ADDED] you can now export RectTransforms

Author: AJubrey

Assets/FbxExporters/Editor/FbxExporter.cs

@@ -683,21 +683,41 @@ protected void ExportTransform (UnityEngine.Transform unityTransform, FbxNode fb
                 FbxDouble3 fbxRotate;
                 UnityEngine.Vector3 unityScale;
 
+                RectTransform uiComponent = unityTransform.gameObject.GetComponent<RectTransform>();
+
                 switch (exportType) {
                 case TransformExportType.Reset:
                     unityTranslate = Vector3.zero;
                     fbxRotate = new FbxDouble3 (0);
                     unityScale = Vector3.one;
+                    if (uiComponent != null) // if this component is a RectTransform
+                        {
+                        unityTranslate = uiComponent.localPosition;
+                        fbxRotate = ConvertQuaternionToXYZEuler(uiComponent.localRotation);
+                        unityScale = uiComponent.localScale;
+                    }
                     break;
                 case TransformExportType.Global:
                     unityTranslate = GetRecenteredTranslation(unityTransform, newCenter);
                     fbxRotate = ConvertQuaternionToXYZEuler(unityTransform.rotation);
                     unityScale = unityTransform.lossyScale;
+                    if (uiComponent != null) // if this component is a RectTransform
+                    {
+                        unityTranslate = GetRecenteredTranslation(uiComponent.transform, newCenter);
+                        fbxRotate = ConvertQuaternionToXYZEuler(uiComponent.rotation);
+                        unityScale = uiComponent.lossyScale;
+                    }
                     break;
                 default: /*case TransformExportType.Local*/
                     unityTranslate = unityTransform.localPosition;
                     fbxRotate = ConvertQuaternionToXYZEuler(unityTransform.localRotation);
                     unityScale = unityTransform.localScale;
+                    if(uiComponent != null) // if this component is a RectTransform
+                        {
+                        unityTranslate = uiComponent.localPosition;
+                        fbxRotate = ConvertQuaternionToXYZEuler(uiComponent.localRotation);
+                        unityScale = uiComponent.localScale;
+                    }
                     break;
                 }
 

Assets/FbxExporters/Editor/FbxPrefabAutoUpdater.cs

@@ -983,13 +983,24 @@ public HashSet<GameObject> ImplementUpdates(FbxPrefab prefabInstance)
                                 prefabComponent = prefabXfo.gameObject.AddComponent(fbxComponent.t);
                                 Log("created component {0}:{1}", nodeName, fbxComponent.t);
                             }
-                            // Check that the component exists before copying to it.
-                            // This happens for Rect Transform components as the fbx
-                            // contains a Transform which it tries to add/update on the
-                            // prefab, but fails because you cannot have both a Transform
-                            // and a Rect Transform
-                            // UNI-29179 TODO: better handling of Rect Transforms
+
                             if (!prefabComponent) {
+                                
+                                index = prefabComponents.FindIndex(x => x.GetType() == typeof(RectTransform));
+                                prefabComponent = prefabComponents[index];
+                                prefabComponents.RemoveAt(index);
+
+                                GameObject tempGameObject = new GameObject();
+                                Transform tempTransform = tempGameObject.transform;
+
+                                UnityEditor.EditorJsonUtility.FromJsonOverwrite(fbxComponent.jsonValue, tempTransform);
+
+                                prefabComponent.gameObject.GetComponent<RectTransform>().rotation = tempTransform.rotation;
+                                prefabComponent.gameObject.GetComponent<RectTransform>().position = tempTransform.position;
+                                prefabComponent.gameObject.GetComponent<RectTransform>().localScale = tempTransform.localScale;
+                                GameObject.DestroyImmediate(tempGameObject);
+
+                                Log("updated component {0}:{1}", nodeName, typeof(RectTransform));
                                 continue;
                             }
                             // Now set the values.