io_scene_fbx/__init__.py

@@ -5,7 +5,7 @@
 bl_info = {
     "name": "FBX format",
     "author": "Campbell Barton, Bastien Montagne, Jens Restemeier, @Mysteryem",
-    "version": (5, 8, 0),
+    "version": (5, 8, 1),
     "blender": (3, 6, 0),
     "location": "File > Import-Export",
     "description": "FBX IO meshes, UVs, vertex colors, materials, textures, cameras, lamps and actions",

io_scene_fbx/export_fbx_bin.py

@@ -2592,7 +2592,6 @@ def fbx_data_from_scene(scene, depsgraph, settings):
         if ob_obj.type not in BLENDER_OBJECT_TYPES_MESHLIKE:
             continue
         ob = ob_obj.bdata
-        use_org_data = True
         org_ob_obj = None
 
         # Do not want to systematically recreate a new mesh for dupliobject instances, kind of break purpose of those.
@@ -2602,16 +2601,28 @@ def fbx_data_from_scene(scene, depsgraph, settings):
                 data_meshes[ob_obj] = data_meshes[org_ob_obj]
                 continue
 
-        is_ob_material = any(ms.link == 'OBJECT' for ms in ob.material_slots)
+        # There are 4 different cases for what we need to do with the original data of each Object:
+        # 1) The original data can be used without changes.
+        # 2) A copy of the original data needs to be made.
+        #  - If an export option modifies the data, e.g. Triangulate Faces is enabled.
+        #  - If the Object has Object-linked materials. This is because our current mapping of materials to FBX requires
+        #    that multiple Objects sharing a single mesh must have the same materials.
+        # 3) The Object needs to be converted to a mesh.
+        #  - All mesh-like Objects that are not meshes need to be converted to a mesh in order to be exported.
+        # 4) The Object needs to be evaluated and then converted to a mesh.
+        #  - Whenever use_mesh_modifiers is enabled and either there are modifiers to apply or the Object needs to be
+        #    converted to a mesh.
+        # If multiple cases apply to an Object, then only the last applicable case is relevant.
+        do_copy = any(ms.link == 'OBJECT' for ms in ob.material_slots) or settings.use_triangles
+        do_convert = ob.type in BLENDER_OTHER_OBJECT_TYPES
+        do_evaluate = do_convert and settings.use_mesh_modifiers
 
-        if settings.use_mesh_modifiers or settings.use_triangles or ob.type in BLENDER_OTHER_OBJECT_TYPES or is_ob_material:
-            # We cannot use default mesh in that case, or material would not be the right ones...
-            use_org_data = not (is_ob_material or ob.type in BLENDER_OTHER_OBJECT_TYPES)
+        # If the Object is a mesh, and we're applying modifiers, check if there are actually any modifiers to apply.
+        # If there are then the mesh will need to be evaluated, and we may need to make some temporary changes to the
+        # modifiers or scene before the mesh is evaluated.
         backup_pose_positions = []
         tmp_mods = []
-            if use_org_data and ob.type == 'MESH':
-                if settings.use_triangles:
-                    use_org_data = False
+        if ob.type == 'MESH' and settings.use_mesh_modifiers:
             # No need to create a new mesh in this case, if no modifier is active!
             last_subsurf = None
             for mod in ob.modifiers:
@@ -2636,34 +2647,26 @@ def fbx_data_from_scene(scene, depsgraph, settings):
                     # found applicable subsurf modifier.
                     if settings.use_subsurf and mod.type == 'SUBSURF' and mod.subdivision_type == 'CATMULL_CLARK':
                         if last_subsurf:
-                                use_org_data = False
+                            do_evaluate = True
                         last_subsurf = mod
                     else:
-                            use_org_data = False
+                        do_evaluate = True
             if settings.use_subsurf and last_subsurf:
                 # XXX: When exporting with subsurf information temporarily disable
                 # the last subsurf modifier.
                 tmp_mods.append((last_subsurf, last_subsurf.show_render, last_subsurf.show_viewport))
-                    last_subsurf.show_render = False
-                    last_subsurf.show_viewport = False
-            if not use_org_data:
+
+        if do_evaluate:
             # If modifiers has been altered need to update dependency graph.
             if backup_pose_positions or tmp_mods:
                 depsgraph.update()
-                ob_to_convert = ob.evaluated_get(depsgraph) if settings.use_mesh_modifiers else ob
+            ob_to_convert = ob.evaluated_get(depsgraph)
             # NOTE: The dependency graph might be re-evaluating multiple times, which could
             # potentially free the mesh created early on. So we put those meshes to bmain and
-                # free them afterwards. Not ideal but ensures correct ownerwhip.
+            # free them afterwards. Not ideal but ensures correct ownership.
             tmp_me = bpy.data.meshes.new_from_object(
                 ob_to_convert, preserve_all_data_layers=True, depsgraph=depsgraph)
-                # Triangulate the mesh if requested
-                if settings.use_triangles:
-                    import bmesh
-                    bm = bmesh.new()
-                    bm.from_mesh(tmp_me)
-                    bmesh.ops.triangulate(bm, faces=bm.faces)
-                    bm.to_mesh(tmp_me)
-                    bm.free()
+
             # Usually the materials of the evaluated object will be the same, but modifiers, such as Geometry Nodes,
             # can change the materials.
             orig_mats = tuple(slot.material for slot in ob.material_slots)
@@ -2672,7 +2675,29 @@ def fbx_data_from_scene(scene, depsgraph, settings):
             if orig_mats != eval_mats:
                 # Override the default behaviour of getting materials from ob_obj.bdata.material_slots.
                 ob_obj.override_materials = eval_mats
+        elif do_convert:
+            tmp_me = bpy.data.meshes.new_from_object(ob, preserve_all_data_layers=True, depsgraph=depsgraph)
+        elif do_copy:
+            # bpy.data.meshes.new_from_object removes shape keys (see #104714), so create a copy of the mesh instead.
+            tmp_me = ob.data.copy()
+        else:
+            tmp_me = None
+
+        if tmp_me is None:
+            # Use the original data of this Object.
+            data_meshes[ob_obj] = (get_blenderID_key(ob.data), ob.data, False)
+        else:
+            # Triangulate the mesh if requested
+            if settings.use_triangles:
+                import bmesh
+                bm = bmesh.new()
+                bm.from_mesh(tmp_me)
+                bmesh.ops.triangulate(bm, faces=bm.faces)
+                bm.to_mesh(tmp_me)
+                bm.free()
+            # A temporary mesh was created for this Object, which should be deleted once the export is complete.
             data_meshes[ob_obj] = (get_blenderID_key(tmp_me), tmp_me, True)
+
         # Change armatures back.
         for armature, pose_position in backup_pose_positions:
             print((armature, pose_position))
@@ -2684,8 +2709,6 @@ def fbx_data_from_scene(scene, depsgraph, settings):
             mod.show_viewport = show_viewport
         if backup_pose_positions or tmp_mods:
             depsgraph.update()
-        if use_org_data:
-            data_meshes[ob_obj] = (get_blenderID_key(ob.data), ob.data, False)
 
         # In case "real" source object of that dupli did not yet still existed in data_meshes, create it now!
         if org_ob_obj is not None: