Fix for root bone being incorrectly oriented if it wasn't at the identity rotation in the bind pose

umodel, for some reason, exports some models with no bones. For
compatibility and convenience, an armature with no bones may as well not
exist, so we treat it as though it doesn't on export, and a single fake
root bone is added for maximum compatibility.

README.md

@@ -10,7 +10,7 @@ This Blender addon allows you to import and export meshes and animations to and
 | Blender Version                                              | Addon Version                                                                  | Long Term Support |
 |--------------------------------------------------------------|--------------------------------------------------------------------------------|-------------------|
 | 4.0+                                                         | [latest](https://github.com/DarklightGames/io_scene_psk_psa/releases/latest)   | TBD               |
-| [3.4 - 3.6](https://www.blender.org/download/lts/3-6/)       | [5.0.5](https://github.com/DarklightGames/io_scene_psk_psa/releases/tag/5.0.5) | ✅️ June 2025      |
+| [3.4 - 3.6](https://www.blender.org/download/lts/3-6/)       | [5.0.6](https://github.com/DarklightGames/io_scene_psk_psa/releases/tag/5.0.6) | ✅️ June 2025      |
 | [2.93 - 3.3](https://www.blender.org/download/releases/3-3/) | [4.3.0](https://github.com/DarklightGames/io_scene_psk_psa/releases/tag/4.3.0) | ✅️ September 2024 |
 
 Bug fixes will be issued for legacy addon versions that are under [Blender's LTS maintenance period](https://www.blender.org/download/lts/). Once the LTS period has ended, legacy addon versions will no longer be supported by the maintainers of this repository, although we will accept pull requests for bug fixes. 

io_scene_psk_psa/__init__.py

@@ -36,6 +36,7 @@ if 'bpy' in locals():
     importlib.reload(psa_reader)
     importlib.reload(psa_writer)
     importlib.reload(psa_builder)
+    importlib.reload(psa_importer)
     importlib.reload(psa_export_properties)
     importlib.reload(psa_export_operators)
     importlib.reload(psa_export_ui)

io_scene_psk_psa/psa/importer.py

@@ -153,7 +153,8 @@ def import_psa(context: Context, psa_reader: PsaReader, armature_object: Object,
             import_bone.original_rotation.conjugate()
         else:
             import_bone.original_location = armature_bone.matrix_local.translation.copy()
-            import_bone.original_rotation = armature_bone.matrix_local.to_quaternion()
+            import_bone.original_rotation = armature_bone.matrix_local.to_quaternion().conjugated()
+
         import_bone.post_rotation = import_bone.original_rotation.conjugated()
 
     context.window_manager.progress_begin(0, len(sequences))

io_scene_psk_psa/psk/builder.py

@@ -76,9 +76,9 @@ def build_psk(context, options: PskBuildOptions) -> PskBuildResult:
     psk = Psk()
     bones = []
 
-    if armature_object is None:
-        # If the mesh has no armature object, simply assign it a dummy bone at the root to satisfy the requirement
-        # that a PSK file must have at least one bone.
+    if armature_object is None or len(armature_object.data.bones) == 0:
+        # If the mesh has no armature object or no bones, simply assign it a dummy bone at the root to satisfy the
+        # requirement that a PSK file must have at least one bone.
         psk_bone = Psk.Bone()
         psk_bone.name = bytes('root', encoding='windows-1252')
         psk_bone.flags = 0