Fix for error when exporting mesh with no armature

io_scene_psk_psa/psk/builder.py

@@ -130,7 +130,7 @@ def build_psk(context, input_objects: PskInputObjects, options: PskBuildOptions)
         psk_bone.children_count = 0
         psk_bone.parent_index = 0
         psk_bone.location = Vector3.zero()
-        psk_bone.rotation = coordinate_system_default_rotation
+        psk_bone.rotation = Quaternion.from_bpy_quaternion(coordinate_system_default_rotation)
         psk.bones.append(psk_bone)
     else:
         bone_names = get_export_bone_names(armature_object, options.bone_filter_mode, options.bone_collection_indices)

io_scene_psk_psa/shared/data.py

@@ -2,7 +2,7 @@ from ctypes import *
 from typing import Tuple
 
 from bpy.props import EnumProperty
-from mathutils import Vector, Matrix
+from mathutils import Vector, Matrix, Quaternion as BpyQuaternion
 
 
 class Color(Structure):
@@ -84,6 +84,15 @@ class Quaternion(Structure):
     def identity(cls):
         return Quaternion(0, 0, 0, 1)
 
+    @classmethod
+    def from_bpy_quaternion(cls, other: BpyQuaternion) -> BpyQuaternion:
+        quaternion = Quaternion()
+        quaternion.x = other.x
+        quaternion.y = other.y
+        quaternion.z = other.z
+        quaternion.w = other.w
+        return quaternion
+
 
 class Section(Structure):
     _fields_ = [