Fixed duplicate code issue

# Conflicts:
#	io_scene_psk_psa/psa/importer.py

README.md

@@ -5,11 +5,12 @@
 
 This Blender addon allows you to import and export meshes and animations to and from the [PSK and PSA file formats](https://wiki.beyondunreal.com/PSK_%26_PSA_file_formats) used in many versions of the Unreal Engine.
 
-## Compatibility
+# Compatibility
 
 | Blender Version                                            | Addon Version                                                                  | Long Term Support |
-|--------------------------------------------------------------|--------------------------------------------------------------------------------|-------------------|
+|------------------------------------------------------------|--------------------------------------------------------------------------------|-------------------|
-| 4.0+                                                         | [latest](https://github.com/DarklightGames/io_scene_psk_psa/releases/latest)   | TBD               |
+| [4.1](https://www.blender.org/download/releases/4-1/)      | [latest](https://github.com/DarklightGames/io_scene_psk_psa/releases/latest)   | TBD               |
+| [4.0](https://www.blender.org/download/releases/4-0/)      | [6.2.1](https://github.com/DarklightGames/io_scene_psk_psa/releases/tag/6.2.1) | TBD               |                                      
 | [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 |
 

io_scene_psk_psa/__init__.py

@@ -3,8 +3,8 @@ from bpy.app.handlers import persistent
 bl_info = {
     'name': 'PSK/PSA Importer/Exporter',
     'author': 'Colin Basnett, Yurii Ti',
-    'version': (6, 2, 0),
+    'version': (7, 0, 0),
-    'blender': (4, 0, 0),
+    'blender': (4, 1, 0),
     'description': 'PSK/PSA Import/Export (.psk/.psa)',
     'warning': '',
     'doc_url': 'https://github.com/DarklightGames/io_scene_psk_psa',

io_scene_psk_psa/psa/config.py

@@ -14,7 +14,7 @@ class PsaConfig:
 
 
 def _load_config_file(file_path: str) -> ConfigParser:
-    '''
+    """
     UEViewer exports a dialect of INI files that is not compatible with Python's ConfigParser.
     Specifically, it allows values in this format:
 
@@ -24,7 +24,7 @@ def _load_config_file(file_path: str) -> ConfigParser:
 
     This is not allowed in Python's ConfigParser, which requires a '=' character after each key name.
     To work around this, we'll modify the file to add the '=' character after each key name if it is missing.
-    '''
+    """
     with open(file_path, 'r') as f:
         lines = f.read().split('\n')
 
@@ -41,7 +41,7 @@ def _load_config_file(file_path: str) -> ConfigParser:
 def _get_bone_flags_from_value(value: str) -> int:
     match value:
         case 'all':
-            return (REMOVE_TRACK_LOCATION | REMOVE_TRACK_ROTATION)
+            return REMOVE_TRACK_LOCATION | REMOVE_TRACK_ROTATION
         case 'trans':
             return REMOVE_TRACK_LOCATION
         case 'rot':

io_scene_psk_psa/psa/export/operators.py

@@ -91,14 +91,15 @@ def update_actions_and_timeline_markers(context: Context, armature: Armature):
 
 
 def get_sequence_fps(context: Context, fps_source: str, fps_custom: float, actions: Iterable[Action]) -> float:
-    if fps_source == 'SCENE':
+    match fps_source:
+        case 'SCENE':
             return context.scene.render.fps
-    elif fps_source == 'CUSTOM':
+        case 'CUSTOM':
             return fps_custom
-    elif fps_source == 'ACTION_METADATA':
+        case 'ACTION_METADATA':
             # Get the minimum value of action metadata FPS values.
             return min([action.psa_export.fps for action in actions])
-    else:
+        case _:
             raise RuntimeError(f'Invalid FPS source "{fps_source}"')
 
 

io_scene_psk_psa/psa/export/ui.py

@@ -32,7 +32,6 @@ class PSA_UL_export_sequences(UIList):
         subrow = row.row(align=True)
         subrow.prop(pg, 'sequence_filter_name', text='')
         subrow.prop(pg, 'sequence_use_filter_invert', text='', icon='ARROW_LEFTRIGHT')
-        # subrow.prop(pg, 'sequence_use_filter_sort_reverse', text='', icon='SORT_ASC')
 
         if pg.sequence_source == 'ACTIONS':
             subrow = row.row(align=True)
@@ -44,7 +43,6 @@ class PSA_UL_export_sequences(UIList):
         pg = getattr(context.scene, 'psa_export')
         actions = getattr(data, prop)
         flt_flags = filter_sequences(pg, actions)
-        # flt_neworder = bpy.types.UI_UL_list.sort_items_by_name(actions, 'name')
         flt_neworder = list(range(len(actions)))
         return flt_flags, flt_neworder
 

io_scene_psk_psa/psa/import_/operators.py

@@ -2,7 +2,7 @@ import os
 from pathlib import Path
 
 from bpy.props import StringProperty
-from bpy.types import Operator, Event, Context
+from bpy.types import Operator, Event, Context, FileHandler
 from bpy_extras.io_utils import ImportHelper
 
 from .properties import get_visible_sequences
@@ -89,23 +89,6 @@ class PSA_OT_import_sequences_deselect_all(Operator):
         return {'FINISHED'}
 
 
-class PSA_OT_import_select_file(Operator):
-    bl_idname = 'psa_import.select_file'
-    bl_label = 'Select'
-    bl_options = {'INTERNAL'}
-    bl_description = 'Select a PSA file from which to import animations'
-    filepath: StringProperty(subtype='FILE_PATH')
-    filter_glob: StringProperty(default='*.psa', options={'HIDDEN'})
-
-    def execute(self, context):
-        getattr(context.scene, 'psa_import').psa_file_path = self.filepath
-        return {'FINISHED'}
-
-    def invoke(self, context, event):
-        context.window_manager.fileselect_add(self)
-        return {'RUNNING_MODAL'}
-
-
 def load_psa_file(context, filepath: str):
     pg = context.scene.psa_import
     pg.sequence_list.clear()
@@ -207,18 +190,18 @@ class PSA_OT_import(Operator, ImportHelper):
         layout = self.layout
         pg = getattr(context.scene, 'psa_import')
 
+        sequences_header, sequences_panel = layout.panel('sequences_panel_id', default_closed=False)
+        sequences_header.label(text='Sequences')
+
+        if sequences_panel:
             if pg.psa_error:
-            row = layout.row()
+                row = sequences_panel.row()
                 row.label(text='Select a PSA file', icon='ERROR')
             else:
-            box = layout.box()
-
-            box.label(text=f'Sequences ({len(pg.sequence_list)})', icon='ARMATURE_DATA')
-
                 # Select buttons.
                 rows = max(3, min(len(pg.sequence_list), 10))
 
-            row = box.row()
+                row = sequences_panel.row()
                 col = row.column()
 
                 row2 = col.row(align=True)
@@ -230,44 +213,59 @@ class PSA_OT_import(Operator, ImportHelper):
                 col = col.row()
                 col.template_list('PSA_UL_import_sequences', '', pg, 'sequence_list', pg, 'sequence_list_index', rows=rows)
 
-        col = layout.column(heading='')
+            col = sequences_panel.column(heading='')
             col.use_property_split = True
             col.use_property_decorate = False
+            col.prop(pg, 'fps_source')
+            if pg.fps_source == 'CUSTOM':
+                col.prop(pg, 'fps_custom')
             col.prop(pg, 'should_overwrite')
+            col.prop(pg, 'should_use_action_name_prefix')
+            if pg.should_use_action_name_prefix:
+                col.prop(pg, 'action_name_prefix')
 
-        col = layout.column(heading='Write')
+        data_header, data_panel = layout.panel('data_panel_id', default_closed=False)
+        data_header.label(text='Data')
+
+        if data_panel:
+            col = data_panel.column(heading='Write')
             col.use_property_split = True
             col.use_property_decorate = False
             col.prop(pg, 'should_write_keyframes')
             col.prop(pg, 'should_write_metadata')
 
-        col = layout.column()
+            if pg.should_write_keyframes:
+                col = col.column(heading='Keyframes')
+                col.use_property_split = True
+                col.use_property_decorate = False
+                col.prop(pg, 'should_convert_to_samples')
+
+        advanced_header, advanced_panel = layout.panel('advanced_panel_id', default_closed=True)
+        advanced_header.label(text='Advanced')
+
+        if advanced_panel:
+            col = advanced_panel.column()
             col.use_property_split = True
             col.use_property_decorate = False
             col.prop(pg, 'bone_mapping_mode')
 
-        if pg.should_write_keyframes:
+            col = advanced_panel.column(heading='Options')
-            col = layout.column(heading='Keyframes')
-            col.use_property_split = True
-            col.use_property_decorate = False
-            col.prop(pg, 'should_convert_to_samples')
-            col.separator()
-            # FPS
-            col.prop(pg, 'fps_source')
-            if pg.fps_source == 'CUSTOM':
-                col.prop(pg, 'fps_custom')
-
-        col = layout.column(heading='Options')
             col.use_property_split = True
             col.use_property_decorate = False
             col.prop(pg, 'should_use_fake_user')
             col.prop(pg, 'should_stash')
             col.prop(pg, 'should_use_config_file')
 
-        col.prop(pg, 'should_use_action_name_prefix')
 
-        if pg.should_use_action_name_prefix:
+class PSA_FH_import(FileHandler):
-            col.prop(pg, 'action_name_prefix')
+    bl_idname = 'PSA_FH_import'
+    bl_label = 'File handler for Unreal PSA import'
+    bl_import_operator = 'psa_import.import'
+    bl_file_extensions = '.psa'
+
+    @classmethod
+    def poll_drop(cls, context: Context):
+        return context.area and context.area.type == 'VIEW_3D'
 
 
 classes = (
@@ -275,5 +273,5 @@ classes = (
     PSA_OT_import_sequences_deselect_all,
     PSA_OT_import_sequences_from_text,
     PSA_OT_import,
-    PSA_OT_import_select_file,
+    PSA_FH_import,
 )

io_scene_psk_psa/psa/import_/properties.py

@@ -71,17 +71,18 @@ class PSA_PG_import(PropertyGroup):
             ('EXACT', 'Exact', 'Bone names must match exactly.', 'EXACT', 0),
             ('CASE_INSENSITIVE', 'Case Insensitive', 'Bones names must match, ignoring case (e.g., the bone PSA bone '
              '\'root\' can be mapped to the armature bone \'Root\')', 'CASE_INSENSITIVE', 1),
-        )
+        ),
+        default='CASE_INSENSITIVE'
     )
     fps_source: EnumProperty(name='FPS Source', items=(
         ('SEQUENCE', 'Sequence', 'The sequence frame rate matches the original frame rate', 'ACTION', 0),
-        ('SCENE', 'Scene', 'The sequence frame rate dilates to match that of the scene', 'SCENE_DATA', 1),
+        ('SCENE', 'Scene', 'The sequence is resampled to the frame rate of the scene', 'SCENE_DATA', 1),
-        ('CUSTOM', 'Custom', 'The sequence frame rate dilates to match a custom frame rate', 2),
+        ('CUSTOM', 'Custom', 'The sequence is resampled to a custom frame rate', 2),
     ))
     fps_custom: FloatProperty(
         default=30.0,
         name='Custom FPS',
-        description='The frame rate to which the imported actions will be converted',
+        description='The frame rate to which the imported sequences will be resampled to',
         options=empty_set,
         min=1.0,
         soft_min=1.0,

io_scene_psk_psa/psa/importer.py

@@ -2,7 +2,7 @@ import typing
 from typing import List, Optional
 
 import bpy
-import numpy
+import numpy as np
 from bpy.types import FCurve, Object, Context
 from mathutils import Vector, Quaternion
 
@@ -46,16 +46,16 @@ def _calculate_fcurve_data(import_bone: ImportBone, key_data: typing.Iterable[fl
     key_location = Vector(key_data[4:])
     q = import_bone.post_rotation.copy()
     q.rotate(import_bone.original_rotation)
-    quat = q
+    rotation = q
     q = import_bone.post_rotation.copy()
     if import_bone.parent is None:
         q.rotate(key_rotation.conjugated())
     else:
         q.rotate(key_rotation)
-    quat.rotate(q.conjugated())
+    rotation.rotate(q.conjugated())
-    loc = key_location - import_bone.original_location
+    location = key_location - import_bone.original_location
-    loc.rotate(import_bone.post_rotation.conjugated())
+    location.rotate(import_bone.post_rotation.conjugated())
-    return quat.w, quat.x, quat.y, quat.z, loc.x, loc.y, loc.z
+    return rotation.w, rotation.x, rotation.y, rotation.z, location.x, location.y, location.z
 
 
 class PsaImportResult:
@@ -64,12 +64,12 @@ class PsaImportResult:
 
 
 def _get_armature_bone_index_for_psa_bone(psa_bone_name: str, armature_bone_names: List[str], bone_mapping_mode: str = 'EXACT') -> Optional[int]:
-    '''
+    """
     @param psa_bone_name: The name of the PSA bone.
     @param armature_bone_names: The names of the bones in the armature.
     @param bone_mapping_mode: One of 'EXACT' or 'CASE_INSENSITIVE'.
     @return: The index of the armature bone that corresponds to the given PSA bone, or None if no such bone exists.
-    '''
+    """
     for armature_bone_index, armature_bone_name in enumerate(armature_bone_names):
         if bone_mapping_mode == 'CASE_INSENSITIVE':
             if armature_bone_name.lower() == psa_bone_name.lower():
@@ -79,6 +79,51 @@ def _get_armature_bone_index_for_psa_bone(psa_bone_name: str, armature_bone_name
                 return armature_bone_index
     return None
 
+def _get_sample_frame_times(source_frame_count: int, frame_step: float) -> typing.Iterable[float]:
+    # TODO: for correctness, we should also emit the target frame time as well (because the last frame can be a
+    #  fractional frame).
+    time = 0.0
+    while time < source_frame_count - 1:
+        yield time
+        time += frame_step
+    yield source_frame_count - 1
+
+def _resample_sequence_data_matrix(sequence_data_matrix: np.ndarray, frame_step: float = 1.0) -> np.ndarray:
+    """
+    Resamples the sequence data matrix to the target frame count.
+    @param sequence_data_matrix: FxBx7 matrix where F is the number of frames, B is the number of bones, and X is the
+    number of data elements per bone.
+    @param frame_step: The step between frames in the resampled sequence.
+    @return: The resampled sequence data matrix, or sequence_data_matrix if no resampling is necessary.
+    """
+    if frame_step == 1.0:
+        # No resampling is necessary.
+        return sequence_data_matrix
+
+    source_frame_count, bone_count = sequence_data_matrix.shape[:2]
+    sample_frame_times = list(_get_sample_frame_times(source_frame_count, frame_step))
+    target_frame_count = len(sample_frame_times)
+    resampled_sequence_data_matrix = np.zeros((target_frame_count, bone_count, 7), dtype=float)
+
+    for sample_frame_index, sample_frame_time in enumerate(sample_frame_times):
+        frame_index = int(sample_frame_time)
+        if sample_frame_time % 1.0 == 0.0:
+            # Sample time has no fractional part, so just copy the frame.
+            resampled_sequence_data_matrix[sample_frame_index, :, :] = sequence_data_matrix[frame_index, :, :]
+        else:
+            # Sample time has a fractional part, so interpolate between two frames.
+            next_frame_index = frame_index + 1
+            for bone_index in range(bone_count):
+                source_frame_1_data = sequence_data_matrix[frame_index, bone_index, :]
+                source_frame_2_data = sequence_data_matrix[next_frame_index, bone_index, :]
+                factor = sample_frame_time - frame_index
+                q = Quaternion((source_frame_1_data[:4])).slerp(Quaternion((source_frame_2_data[:4])), factor)
+                q.normalize()
+                l = Vector(source_frame_1_data[4:]).lerp(Vector(source_frame_2_data[4:]), factor)
+                resampled_sequence_data_matrix[sample_frame_index, bone_index, :] = q.w, q.x, q.y, q.z, l.x, l.y, l.z
+
+    return resampled_sequence_data_matrix
+
 
 def import_psa(context: Context, psa_reader: PsaReader, armature_object: Object, options: PsaImportOptions) -> PsaImportResult:
     result = PsaImportResult()
@@ -98,7 +143,7 @@ def import_psa(context: Context, psa_reader: PsaReader, armature_object: Object,
         if armature_bone_index is not None:
             # Ensure that no other PSA bone has been mapped to this armature bone yet.
             if armature_bone_index not in armature_to_psa_bone_indices:
-                psa_to_armature_bone_indices[psa_bone_index] = armature_bone_names.index(psa_bone_name)
+                psa_to_armature_bone_indices[psa_bone_index] = armature_bone_index
                 armature_to_psa_bone_indices[armature_bone_index] = psa_bone_index
             else:
                 # This armature bone has already been mapped to a PSA bone.
@@ -127,7 +172,7 @@ def import_psa(context: Context, psa_reader: PsaReader, armature_object: Object,
 
     # Create intermediate bone data for import operations.
     import_bones = []
-    import_bones_dict = dict()
+    psa_bone_names_to_import_bones = dict()
 
     for (psa_bone_index, psa_bone), psa_bone_name in zip(enumerate(psa_reader.bones), psa_bone_names):
         if psa_bone_index not in psa_to_armature_bone_indices:
@@ -137,15 +182,22 @@ def import_psa(context: Context, psa_reader: PsaReader, armature_object: Object,
         import_bone = ImportBone(psa_bone)
         import_bone.armature_bone = armature_data.bones[psa_bone_name]
         import_bone.pose_bone = armature_object.pose.bones[psa_bone_name]
-        import_bones_dict[psa_bone_name] = import_bone
+        psa_bone_names_to_import_bones[psa_bone_name] = import_bone
         import_bones.append(import_bone)
 
+    bones_with_missing_parents = []
+
     for import_bone in filter(lambda x: x is not None, import_bones):
         armature_bone = import_bone.armature_bone
-        if armature_bone.parent is not None and armature_bone.parent.name in psa_bone_names:
+        has_parent = armature_bone.parent is not None
-            import_bone.parent = import_bones_dict[armature_bone.parent.name]
+        if has_parent:
+            if armature_bone.parent.name in psa_bone_names:
+                import_bone.parent = psa_bone_names_to_import_bones[armature_bone.parent.name]
+            else:
+                # Add a warning if the parent bone is not in the PSA.
+                bones_with_missing_parents.append(armature_bone)
         # Calculate the original location & rotation of each bone (in world-space maybe?)
-        if import_bone.parent is not None:
+        if has_parent:
             import_bone.original_location = armature_bone.matrix_local.translation - armature_bone.parent.matrix_local.translation
             import_bone.original_location.rotate(armature_bone.parent.matrix_local.to_quaternion().conjugated())
             import_bone.original_rotation = armature_bone.matrix_local.to_quaternion()
@@ -153,9 +205,16 @@ 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()
 
+    # Warn about bones with missing parents.
+    if len(bones_with_missing_parents) > 0:
+        count = len(bones_with_missing_parents)
+        message = f'{count} bone(s) have parents that are not present in the PSA:\n' + str([x.name for x in bones_with_missing_parents])
+        result.warnings.append(message)
+
     context.window_manager.progress_begin(0, len(sequences))
 
     # Create and populate the data for new sequences.
@@ -186,12 +245,9 @@ def import_psa(context: Context, psa_reader: PsaReader, armature_object: Object,
             case _:
                 raise ValueError(f'Unknown FPS source: {options.fps_source}')
 
-        keyframe_time_dilation = target_fps / sequence.fps
-
         if options.should_write_keyframes:
-            # Remove existing f-curves (replace with action.fcurves.clear() in Blender 3.2)
+            # Remove existing f-curves.
-            while len(action.fcurves) > 0:
+            action.fcurves.clear()
-                action.fcurves.remove(action.fcurves[-1])
 
             # Create f-curves for the rotation and location of each bone.
             for psa_bone_index, armature_bone_index in psa_to_armature_bone_indices.items():
@@ -225,19 +281,25 @@ def import_psa(context: Context, psa_reader: PsaReader, armature_object: Object,
                     # Calculate the local-space key data for the bone.
                     sequence_data_matrix[frame_index, bone_index] = _calculate_fcurve_data(import_bone, key_data)
 
-            # Write the keyframes out.
+            # Resample the sequence data to the target FPS.
-            fcurve_data = numpy.zeros(2 * sequence.frame_count, dtype=float)
+            # If the target frame count is the same as the source frame count, this will be a no-op.
+            resampled_sequence_data_matrix = _resample_sequence_data_matrix(sequence_data_matrix,
+                                                                            frame_step=sequence.fps / target_fps)
+
+            # Write the keyframes out.
+            # Note that the f-curve data consists of alternating time and value data.
+            target_frame_count = resampled_sequence_data_matrix.shape[0]
+            fcurve_data = np.zeros(2 * target_frame_count, dtype=float)
+            fcurve_data[0::2] = range(0, target_frame_count)
 
-            # Populate the keyframe time data.
-            fcurve_data[0::2] = [x * keyframe_time_dilation for x in range(sequence.frame_count)]
             for bone_index, import_bone in enumerate(import_bones):
                 if import_bone is None:
                     continue
                 for fcurve_index, fcurve in enumerate(import_bone.fcurves):
                     if fcurve is None:
                         continue
-                    fcurve_data[1::2] = sequence_data_matrix[:, bone_index, fcurve_index]
+                    fcurve_data[1::2] = resampled_sequence_data_matrix[:, bone_index, fcurve_index]
-                    fcurve.keyframe_points.add(sequence.frame_count)
+                    fcurve.keyframe_points.add(target_frame_count)
                     fcurve.keyframe_points.foreach_set('co', fcurve_data)
                     for fcurve_keyframe in fcurve.keyframe_points:
                         fcurve_keyframe.interpolation = 'LINEAR'

io_scene_psk_psa/psa/reader.py

@@ -23,11 +23,11 @@ def _try_fix_cue4parse_issue_103(sequences) -> bool:
 
 
 class PsaReader(object):
-    '''
+    """
     This class reads the sequences and bone information immediately upon instantiation and holds onto a file handle.
     The keyframe data is not read into memory upon instantiation due to its potentially very large size.
     To read the key data for a particular sequence, call :read_sequence_keys.
-    '''
+    """
 
     def __init__(self, path):
         self.keys_data_offset: int = 0
@@ -43,11 +43,11 @@ class PsaReader(object):
         return self.psa.sequences
 
     def read_sequence_data_matrix(self, sequence_name: str) -> np.ndarray:
-        '''
+        """
         Reads and returns the data matrix for the given sequence.
         @param sequence_name: The name of the sequence.
         @return: An FxBx7 matrix where F is the number of frames, B is the number of bones.
-        '''
+        """
         sequence = self.psa.sequences[sequence_name]
         keys = self.read_sequence_keys(sequence_name)
         bone_count = len(self.bones)
@@ -60,12 +60,12 @@ class PsaReader(object):
         return matrix
 
     def read_sequence_keys(self, sequence_name: str) -> List[Psa.Key]:
-        '''
+        """
         Reads and returns the key data for a sequence.
 
         @param sequence_name: The name of the sequence.
         @return: A list of Psa.Keys.
-        '''
+        """
         # Set the file reader to the beginning of the keys data
         sequence = self.psa.sequences[sequence_name]
         data_size = sizeof(Psa.Key)

io_scene_psk_psa/psk/export/properties.py

@@ -3,6 +3,7 @@ from bpy.types import PropertyGroup, Material
 
 from ...types import PSX_PG_bone_collection_list_item
 
+empty_set = set()
 
 class PSK_PG_material_list_item(PropertyGroup):
     material: PointerProperty(type=Material)
@@ -12,7 +13,7 @@ class PSK_PG_material_list_item(PropertyGroup):
 class PSK_PG_export(PropertyGroup):
     bone_filter_mode: EnumProperty(
         name='Bone Filter',
-        options=set(),
+        options=empty_set,
         description='',
         items=(
             ('ALL', 'All', 'All bones will be exported'),

io_scene_psk_psa/psk/import_/operators.py

@@ -2,7 +2,7 @@ import os
 import sys
 
 from bpy.props import StringProperty, BoolProperty, EnumProperty, FloatProperty
-from bpy.types import Operator
+from bpy.types import Operator, FileHandler, Context
 from bpy_extras.io_utils import ImportHelper
 
 from ..importer import PskImportOptions, import_psk
@@ -11,6 +11,17 @@ from ..reader import read_psk
 empty_set = set()
 
 
+class PSK_FH_import(FileHandler):
+    bl_idname = 'PSK_FH_import'
+    bl_label = 'File handler for Unreal PSK/PSKX import'
+    bl_import_operator = 'import_scene.psk'
+    bl_file_extensions = '.psk;.pskx'
+
+    @classmethod
+    def poll_drop(cls, context: Context):
+        return context.area and context.area.type == 'VIEW_3D'
+
+
 class PSK_OT_import(Operator, ImportHelper):
     bl_idname = 'import_scene.psk'
     bl_label = 'Import'
@@ -132,10 +143,11 @@ class PSK_OT_import(Operator, ImportHelper):
         col.use_property_decorate = False
         col.prop(self, 'scale')
 
-        layout.prop(self, 'should_import_mesh')
+        mesh_header, mesh_panel = layout.panel('mesh_panel_id', default_closed=False)
+        mesh_header.prop(self, 'should_import_mesh')
 
-        if self.should_import_mesh:
+        if mesh_panel and self.should_import_mesh:
-            row = layout.row()
+            row = mesh_panel.row()
             col = row.column()
             col.use_property_split = True
             col.use_property_decorate = False
@@ -147,9 +159,11 @@ class PSK_OT_import(Operator, ImportHelper):
                 col.prop(self, 'vertex_color_space')
             col.prop(self, 'should_import_shape_keys', text='Shape Keys')
 
-        layout.prop(self, 'should_import_skeleton')
+        skeleton_header, skeleton_panel = layout.panel('skeleton_panel_id', default_closed=False)
-        if self.should_import_skeleton:
+        skeleton_header.prop(self, 'should_import_skeleton')
-            row = layout.row()
+
+        if skeleton_panel and self.should_import_skeleton:
+            row = skeleton_panel.row()
             col = row.column()
             col.use_property_split = True
             col.use_property_decorate = False
@@ -158,4 +172,5 @@ class PSK_OT_import(Operator, ImportHelper):
 
 classes = (
     PSK_OT_import,
+    PSK_FH_import,
 )

io_scene_psk_psa/psk/importer.py

@@ -231,8 +231,6 @@ def import_psk(psk: Psk, context, options: PskImportOptions) -> PskImportResult:
             for vertex_normal in psk.vertex_normals:
                 normals.append(tuple(vertex_normal))
             mesh_data.normals_split_custom_set_from_vertices(normals)
-            # TODO: This has been removed in 4.1!
-            mesh_data.use_auto_smooth = True
         else:
             mesh_data.shade_smooth()