Fix combined mesh export transforms and child selection (v2.6.9)

src/addons/send2ue/__init__.py

@@ -11,7 +11,7 @@
 bl_info = {
     "name": "Send to Unreal",
     "author": "Epic Games Inc (now a community fork)",
-    "version": (2, 6, 8),
+    "version": (2, 6, 9),
     "blender": (3, 6, 0),
     "location": "Header > Pipeline > Send to Unreal",
     "description": "Sends an asset to the first open Unreal Editor instance on your machine.",

src/addons/send2ue/core/io/fbx_b4.py

@@ -466,8 +466,9 @@ def fbx_data_object_elements(root, ob_obj, scene_data):
             if bpy.context.scene.send2ue.use_object_origin:
                 loc = Vector((0, 0, 0))
 
-        elif ob_obj.type == 'Ellipsis':
-            loc = Vector((loc[0] * SCALE_FACTOR, loc[1] * SCALE_FACTOR, loc[2] * SCALE_FACTOR))
+        elif ob_obj.type == 'EMPTY':
+            if bpy.context.scene.send2ue.use_object_origin:
+                loc = Vector((0, 0, 0))
         elif ob_obj.type == 'MESH':
             # centers mesh object by their object origin
             if bpy.context.scene.send2ue.use_object_origin:
@@ -486,13 +487,66 @@ def fbx_data_object_elements(root, ob_obj, scene_data):
                     # https://github.com/EpicGamesExt/BlenderTools/issues/627
                     empty_object_name = asset_data.get('empty_object_name')
                     if empty_object_name:
-                        empty_object = bpy.data.objects.get(empty_object_name)
-                        empty_world_location = empty_object.matrix_world.to_translation()
-                        loc = Vector((
-                            (object_world_location[0] - empty_world_location[0]) * SCALE_FACTOR,
-                            (object_world_location[1] - empty_world_location[1]) * SCALE_FACTOR,
-                            (object_world_location[2] - empty_world_location[2]) * SCALE_FACTOR
-                        ))
+                        # Check if this is a collision mesh (UBX_, UCP_, USP_, UCX_)
+                        _is_collision = any(
+                            current_object.name.startswith(token + '_')
+                            for token in ('UBX', 'UCP', 'USP', 'UCX')
+                        )
+                        if _is_collision:
+                            import math
+                            _gm = scene_data.settings.global_matrix
+                            empty_object = bpy.data.objects.get(empty_object_name)
+                            _parent_is_empty = (
+                                ob_obj.parent and ob_obj.parent.name == empty_object_name
+                            )
+                            if ob_obj.parent and not _parent_is_empty:
+                                # Child collision (parented to visual mesh, grandchild
+                                # of EMPTY): fbx_object_tx is contaminated because
+                                # fbx_object_matrix's parent correction (lines 1790-1796
+                                # in fbx_utils.py) uses matrix_local which contains
+                                # EMPTY_world^-1 via matrix_parent_inverse. The EMPTY's
+                                # non-uniform display scale leaks into loc/rot/scale.
+                                # Compute clean local transform using matrix_world
+                                # (where EMPTY's influence is fully cancelled) via
+                                # global_space=True which takes the clean is_global path.
+                                _desired_fbx = ob_obj.fbx_object_matrix(scene_data, global_space=True)
+                                _par_world = ob_obj.parent.fbx_object_matrix(
+                                    scene_data, global_space=True
+                                )
+                                _local = _par_world.inverted_safe() @ _desired_fbx
+                                _l, _r, _s = _local.decompose()
+                                loc = Vector(_l)
+                                rot = tuple(math.degrees(a) for a in _r.to_euler('XYZ'))
+                                scale = Vector(_s)
+                            else:
+                                # Root collision (parented to EMPTY or no parent):
+                                # fbx_object_tx IS clean here because the EMPTY is not
+                                # in the export set, so fbx_object_matrix takes the
+                                # is_global path which uses matrix_world (clean).
+                                # Just adjust loc to be EMPTY-relative.
+                                _empty_fbx_pos = _gm @ empty_object.matrix_world.to_translation()
+                                loc = Vector((
+                                    loc[0] - _empty_fbx_pos[0],
+                                    loc[1] - _empty_fbx_pos[1],
+                                    loc[2] - _empty_fbx_pos[2]
+                                ))
+                                # scale from fbx_object_tx already includes
+                                # the unit conversion (100x from global_matrix)
+                                # for root nodes. No additional factor needed.
+                        else:
+                            # Non-collision visual meshes: root FBX nodes with
+                            # correct fbx_object_tx world transforms. Adjust loc
+                            # to center the combined mesh around the EMPTY's
+                            # position (ignoring EMPTY rot/scale which are for
+                            # display only).
+                            empty_object = bpy.data.objects.get(empty_object_name)
+                            _gm = scene_data.settings.global_matrix
+                            _empty_fbx_pos = _gm @ empty_object.matrix_world.to_translation()
+                            loc = Vector((
+                                loc[0] - _empty_fbx_pos[0],
+                                loc[1] - _empty_fbx_pos[1],
+                                loc[2] - _empty_fbx_pos[2]
+                            ))
                     else:
                         asset_world_location = asset_object.matrix_world.to_translation()
                         loc = Vector((
@@ -646,4 +700,4 @@ def fbx_data_bindpose_element(root, me_obj, me, scene_data, arm_obj=None, mat_wo
         export_fbx_bin.fbx_animations_do = original_fbx_animations_do
         export_fbx_bin.fbx_data_armature_elements = original_fbx_data_armature_elements
         export_fbx_bin.fbx_data_object_elements = original_fbx_data_object_elements
-        export_fbx_bin.fbx_data_bindpose_element = original_fbx_data_bindpose_element
+        export_fbx_bin.fbx_data_bindpose_element = original_fbx_data_bindpose_element

src/addons/send2ue/core/utilities.py

@@ -1202,20 +1202,26 @@ def report_path_error_message(layout, send2ue_property, report_text):
 
 def select_all_children(scene_object, object_type, exclude_postfix_tokens=False):
     """
-    Selects all of an objects children.
+    Selects all of an objects children that are in the Export collection hierarchy.
 
     :param object scene_object: A object.
     :param str object_type: The type of object to select.
     :param bool exclude_postfix_tokens: Whether or not to exclude objects that have a postfix token.
     """
+    export_collection = bpy.data.collections.get(ToolInfo.EXPORT_COLLECTION.value)
+    export_objects = set(export_collection.all_objects) if export_collection else set()
     children = scene_object.children or get_meshes_using_armature_modifier(scene_object)
     for child_object in children:
         if child_object.type == object_type:
             if exclude_postfix_tokens:
                 if any(child_object.name.startswith(f'{token.value}_') for token in PreFixToken):
                     continue
 
-            child_object.select_set(True)
+            if child_object not in export_objects:
+                continue
+
+            if child_object.name in bpy.context.view_layer.objects:
+                child_object.select_set(True)
             if child_object.children:
                 select_all_children(child_object, object_type, exclude_postfix_tokens)
 

src/addons/send2ue/release_notes.md

@@ -1,3 +1,12 @@
+## Bug Fixes
+* Fixed combined mesh collision transforms not matching visual mesh positions
+  * [188](https://github.com/poly-hammer/BlenderTools/pull/188)
+* Fixed combined mesh visual mesh transforms when using object origin centering
+* Fixed distortion of rotated instanced meshes when parent EMPTY has display transforms
+* Added EMPTY type check to prevent non-EMPTY parents from entering combined mesh path
+* Fixed crash when child objects exist outside the current View Layer
+* Fixed non-export-collection children being included in combined mesh exports
+
 ## Patch Changes
 * Lowered aggressiveness of socket names
   * [173](https://github.com/poly-hammer/BlenderTools/issues/173)
@@ -6,5 +15,5 @@
 @Daerst
 
 ## Tests Passing On
-* Blender `3.6`, `4.2` (installed from blender.org)
+* Blender `3.6`, `4.2`, `5.0` (installed from blender.org)
 * Unreal `5.3`, `5.4`