Fixed issue where parented bone collections would not be selectable in the bone collection list

Also fixed a bug where the normal export operator was exporting duplicate objects

.github/workflows/main.yml

@@ -6,25 +6,32 @@ on:
     branches: [ "main" ]
   pull_request:
     branches: [ "main" ]
-    
+
 jobs:
   build:
     runs-on: ubuntu-latest
     env:
-      BLENDER_VERSION: blender-4.2.0-beta+v42.d19d23e91f65-linux.x86_64-release
+      BLENDER_VERSION: blender-4.2.0-linux-x64
+      ADDON_NAME: io_scene_psk_psa
     steps:
       - uses: actions/checkout@v3
+      - uses: SebRollen/toml-action@v1.2.0
+        id: read_manifest
+        with:
+          file: '${{ env.ADDON_NAME }}/blender_manifest.toml'
+          field: 'version'
       - name: Set derived environment variables
         run: |
           echo "BLENDER_FILENAME=${{ env.BLENDER_VERSION }}.tar.xz" >> $GITHUB_ENV
-          echo "BLENDER_URL=https://cdn.builder.blender.org/download/daily/${{ env.BLENDER_VERSION }}.tar.xz" >> $GITHUB_ENV
+          echo "BLENDER_URL=https://mirrors.iu13.net/blender/release/Blender4.2/${{ env.BLENDER_VERSION }}.tar.xz" >> $GITHUB_ENV
       - name: Install Blender Dependencies
         run: |
           sudo apt-get install libxxf86vm-dev -y
           sudo apt-get install libxfixes3 -y
           sudo apt-get install libxi-dev -y
           sudo apt-get install libxkbcommon-x11-0 -y
-          sudo apt-get install libgl1-mesa-glx -y
+          sudo apt-get install libgl1 -y
+          sudo apt-get install libglx-mesa0 -y
       - name: Download & Extract Blender
         run: |
           wget -q $BLENDER_URL
@@ -35,14 +42,14 @@ jobs:
           echo "${{ github.workspace }}/${{ env.BLENDER_VERSION }}/" >> $GITHUB_PATH
       - name: Build extension
         run: |
-          pushd ./io_scene_psk_psa
+          pushd ./${{ env.ADDON_NAME }}
           blender --command extension build
           mkdir artifact
-          unzip -q io_scene_psk_psa.zip -d ./artifact
+          unzip -q ${{ env.ADDON_NAME }}-${{ steps.read_manifest.outputs.value }}.zip -d ./artifact
           popd
       - name: Archive addon
         uses: actions/upload-artifact@v4
         with:
-          name: io_scene_psk_psa-${{ github.ref_name }}-${{ github.sha }}
+          name: ${{ env.ADDON_NAME }}-${{ github.ref_name }}-${{ github.sha }}
           path: |
-            ./io_scene_psk_psa/artifact/*
+            ./${{ env.ADDON_NAME }}/artifact/*

README.md

@@ -8,35 +8,41 @@ This Blender addon allows you to import and export meshes and animations to and
 
 This software is licensed under the [GPLv3](https://www.gnu.org/licenses/gpl-3.0.html) license.
 
-# Compatibility
-
-| Blender Version | Addon Version | Long Term Support |
-|-|-|-|
-| [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 |
-
-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. 
-
 # Features
 * Full PSK/PSA import and export capabilities.
 * Non-standard file section data is supported for import only (vertex normals, extra UV channels, vertex colors, shape keys).
 * Fine-grained PSA sequence importing for efficient workflow when working with large PSA files.
-* PSA sequence metadata (e.g., frame rate, sequence name) is preserved on import, allowing this data to be reused on export.
+* PSA sequence metadata (e.g., frame rate) is preserved on import, allowing this data to be reused on export.
 * Specific bone collections can be excluded from PSK/PSA export (useful for excluding non-contributing bones such as IK controllers).
-* PSA sequences can be exported directly from actions or delineated using a scene's [timeline markers](https://docs.blender.org/manual/en/latest/animation/markers.html) or NLA track strips, allowing direct use of the [NLA](https://docs.blender.org/manual/en/latest/editors/nla/index.html) when creating sequences.
+* PSA sequences can be exported directly from actions or delineated using a scene's [timeline markers](https://docs.blender.org/manual/en/latest/animation/markers.html), pose markers, or NLA track strips, allowing direct use of the [NLA](https://docs.blender.org/manual/en/latest/editors/nla/index.html) when creating sequences.
 * Manual re-ordering of material slots when exporting multiple mesh objects.
 
 # Installation
-1. Download the zip file for the latest version from the [releases](https://github.com/DarklightGames/io_export_psk_psa/releases) page.
+For Blender 4.2 and higher, it is recommended to download the latest version from the [Blender Extensions](https://extensions.blender.org/add-ons/io-scene-psk-psa/) platform.
-2. Open Blender 4.0.0 or later.
+
+For Blender 4.1 and lower, you can install the addon manually by following these steps:
+
+1. Download the .zip file of the latest compatible version for your Blender version (see [Legacy Compatibility](#legacy-compatibility)).
+2. Open Blender.
 3. Navigate to the Blender Preferences (`Edit` > `Preferences`).
 4. Select the `Add-ons` tab.
 5. Click the `Install...` button.
 6. Select the .zip file that you downloaded earlier and click `Install Add-on`.
 7. Enable the newly added `Import-Export: PSK/PSA Importer/Exporter` addon.
 
+# Legacy Compatibility
+
+Below is a table of the latest addon versions that are compatible with older versions of Blender. These versions are no longer maintained and may contain bugs that have been fixed in newer versions. It is recommended to use the latest version of the addon for the best experience.
+
+Critical bug fixes may 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 the releases will still be available for download.
+
+| Blender Version| Addon Version                                                                  | Long Term Support |
+|-|--------------------------------------------------------------------------------|-----------------|
+| [4.1](https://www.blender.org/download/releases/4-1/)        | [7.0.0](https://github.com/DarklightGames/io_scene_psk_psa/releases/tag/7.0.0) | No              |
+| [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) | No              |
+| [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  |
+
 # Usage
 ## Exporting a PSK
 1. Select the mesh objects you wish to export.
@@ -71,3 +77,5 @@ The PSA importer creates [Actions](https://docs.blender.org/manual/en/latest/ani
 If preserving the mesh normals of models is important for your workflow, it is *not recommended* to export PSK files from UE Viewer. This is because UE Viewer makes no attempt to reconstruct the original [smoothing groups](https://en.wikipedia.org/wiki/Smoothing_group). As a result, the normals of imported PSK files will be incorrect when imported into Blender and will need to be manually fixed.
 
 As a workaround, it is recommended to export [glTF](https://en.wikipedia.org/wiki/GlTF) meshes out of UE Viewer instead, since the glTF format has support for explicit normals and UE Viewer can correctly preserve the mesh normals on export. Note, however, that the imported glTF armature may have it's bones oriented incorrectly when imported into Blender. To mitigate this, you can combine the armature of PSK and the mesh of the glTF for best results.
+
+There is also an open pull request to add support for exporting explicit normals from UE Viewer in the future: https://github.com/gildor2/UEViewer/pull/277.

io_scene_psk_psa/__init__.py

@@ -6,6 +6,8 @@ if 'bpy' in locals():
     importlib.reload(shared_data)
     importlib.reload(shared_helpers)
     importlib.reload(shared_types)
+    importlib.reload(shared_dfs)
+    importlib.reload(shared_ui)
 
     importlib.reload(psk_data)
     importlib.reload(psk_reader)
@@ -33,6 +35,7 @@ if 'bpy' in locals():
     importlib.reload(psa_import_ui)
 else:
     from .shared import data as shared_data, types as shared_types, helpers as shared_helpers
+    from .shared import dfs as shared_dfs, ui as shared_ui
     from .psk import data as psk_data, builder as psk_builder, writer as psk_writer, \
     importer as psk_importer, properties as psk_properties
     from .psk import reader as psk_reader, ui as psk_ui

io_scene_psk_psa/blender_manifest.toml

@@ -1,6 +1,6 @@
 schema_version = "1.0.0"
 id = "io_scene_psk_psa"
-version = "7.1.0"
+version = "8.0.0"
 name = "Unreal PSK/PSA (.psk/.psa)"
 tagline = "Import and export PSK and PSA files used in Unreal Engine"
 maintainer = "Colin Basnett <cmbasnett@gmail.com>"

io_scene_psk_psa/psa/builder.py

@@ -1,6 +1,7 @@
 from typing import Optional
 
-from bpy.types import Armature, Bone, Action, PoseBone
+from bpy.types import Bone, Action, PoseBone
+from mathutils import Vector
 
 from .data import *
 from ..shared.helpers import *
@@ -13,7 +14,9 @@ class PsaBuildSequence:
             self.frame_start: int = 0
             self.frame_end: int = 0
 
-    def __init__(self):
+    def __init__(self, armature_object: Object, anim_data: AnimData):
+        self.armature_object = armature_object
+        self.anim_data = anim_data
         self.name: str = ''
         self.nla_state: PsaBuildSequence.NlaState = PsaBuildSequence.NlaState()
         self.compression_ratio: float = 1.0
@@ -27,10 +30,11 @@ class PsaBuildOptions:
         self.sequences: List[PsaBuildSequence] = []
         self.bone_filter_mode: str = 'ALL'
         self.bone_collection_indices: List[int] = []
-        self.should_enforce_bone_name_restrictions: bool = False
         self.sequence_name_prefix: str = ''
         self.sequence_name_suffix: str = ''
         self.root_motion: bool = False
+        self.scale = 1.0
+        self.sampling_mode: str = 'INTERPOLATED'  # One of ('INTERPOLATED', 'SUBFRAME')
 
 
 def _get_pose_bone_location_and_rotation(pose_bone: PoseBone, armature_object: Object, options: PsaBuildOptions):
@@ -49,6 +53,8 @@ def _get_pose_bone_location_and_rotation(pose_bone: PoseBone, armature_object: O
     location = pose_bone_matrix.to_translation()
     rotation = pose_bone_matrix.to_quaternion().normalized()
 
+    location *= options.scale
+
     if pose_bone.parent is not None:
         rotation.conjugate()
 
@@ -68,9 +74,6 @@ def build_psa(context: bpy.types.Context, options: PsaBuildOptions) -> Psa:
     # As a result, we need to reconstruct the list of pose bones in the same order as the
     # armature bones.
     bone_names = [x.name for x in bones]
-    pose_bones = [(bone_names.index(bone.name), bone) for bone in armature_object.pose.bones]
-    pose_bones.sort(key=lambda x: x[0])
-    pose_bones = [x[1] for x in pose_bones]
 
     # Get a list of all the bone indices and instigator bones for the bone filter settings.
     export_bone_names = get_export_bone_names(armature_object, options.bone_filter_mode, options.bone_collection_indices)
@@ -78,16 +81,11 @@ def build_psa(context: bpy.types.Context, options: PsaBuildOptions) -> Psa:
 
     # Make the bone lists contain only the bones that are going to be exported.
     bones = [bones[bone_index] for bone_index in bone_indices]
-    pose_bones = [pose_bones[bone_index] for bone_index in bone_indices]
 
     # No bones are going to be exported.
     if len(bones) == 0:
         raise RuntimeError('No bones available for export')
 
-    # Check that all bone names are valid.
-    if options.should_enforce_bone_name_restrictions:
-        check_bone_names(map(lambda bone: bone.name, bones))
-        
     # Build list of PSA bones.
     for bone in bones:
         psa_bone = Psa.Bone()
@@ -145,8 +143,14 @@ def build_psa(context: bpy.types.Context, options: PsaBuildOptions) -> Psa:
     context.window_manager.progress_begin(0, len(options.sequences))
 
     for export_sequence_index, export_sequence in enumerate(options.sequences):
+        # Look up the pose bones for the bones that are going to be exported.
+        pose_bones = [(bone_names.index(bone.name), bone) for bone in export_sequence.armature_object.pose.bones]
+        pose_bones.sort(key=lambda x: x[0])
+        pose_bones = [x[1] for x in pose_bones]
+        pose_bones = [pose_bones[bone_index] for bone_index in bone_indices]
+
         # Link the action to the animation data and update view layer.
-        options.animation_data.action = export_sequence.nla_state.action
+        export_sequence.anim_data.action = export_sequence.nla_state.action
         context.view_layer.update()
 
         frame_start = export_sequence.nla_state.frame_start
@@ -155,7 +159,7 @@ def build_psa(context: bpy.types.Context, options: PsaBuildOptions) -> Psa:
         # Calculate the frame step based on the compression factor.
         frame_extents = abs(frame_end - frame_start)
         frame_count_raw = frame_extents + 1
-        frame_count = max(export_sequence.key_quota, int(frame_count_raw * export_sequence.compression_ratio))
+        frame_count = max(1, max(export_sequence.key_quota, int(frame_count_raw * export_sequence.compression_ratio)))
 
         try:
             frame_step = frame_extents / (frame_count - 1)
@@ -182,24 +186,83 @@ def build_psa(context: bpy.types.Context, options: PsaBuildOptions) -> Psa:
 
         frame = float(frame_start)
 
-        for _ in range(frame_count):
+        def add_key(location: Vector, rotation: Quaternion):
-            context.scene.frame_set(frame=int(frame), subframe=frame % 1.0)
+            key = Psa.Key()
+            key.location.x = location.x
+            key.location.y = location.y
+            key.location.z = location.z
+            key.rotation.x = rotation.x
+            key.rotation.y = rotation.y
+            key.rotation.z = rotation.z
+            key.rotation.w = rotation.w
+            key.time = 1.0 / psa_sequence.fps
+            psa.keys.append(key)
 
-            for pose_bone in pose_bones:
+        match options.sampling_mode:
-                location, rotation = _get_pose_bone_location_and_rotation(pose_bone, armature_object, options)
+            case 'INTERPOLATED':
+                # Used as a store for the last frame's pose bone locations and rotations.
+                last_frame: Optional[int] = None
+                last_frame_bone_poses: List[Tuple[Vector, Quaternion]] = []
 
-                key = Psa.Key()
+                next_frame: Optional[int] = None
-                key.location.x = location.x
+                next_frame_bone_poses: List[Tuple[Vector, Quaternion]] = []
-                key.location.y = location.y
-                key.location.z = location.z
-                key.rotation.x = rotation.x
-                key.rotation.y = rotation.y
-                key.rotation.z = rotation.z
-                key.rotation.w = rotation.w
-                key.time = 1.0 / psa_sequence.fps
-                psa.keys.append(key)
 
-            frame += frame_step
+                for _ in range(frame_count):
+                    if last_frame is None or last_frame != int(frame):
+                        # Populate the bone poses for frame A.
+                        last_frame = int(frame)
+
+                        # TODO: simplify this code and make it easier to follow!
+                        if next_frame == last_frame:
+                            # Simply transfer the data from next_frame to the last_frame so that we don't need to
+                            # resample anything.
+                            last_frame_bone_poses = next_frame_bone_poses.copy()
+                        else:
+                            last_frame_bone_poses.clear()
+                            context.scene.frame_set(frame=last_frame)
+                            for pose_bone in pose_bones:
+                                location, rotation = _get_pose_bone_location_and_rotation(pose_bone,
+                                                                                          export_sequence.armature_object,
+                                                                                          options)
+                                last_frame_bone_poses.append((location, rotation))
+
+                        next_frame = None
+                        next_frame_bone_poses.clear()
+
+                    # If this is not a subframe, just use the last frame's bone poses.
+                    if frame % 1.0 == 0:
+                        for i in range(len(pose_bones)):
+                            add_key(*last_frame_bone_poses[i])
+                    else:
+                        # Otherwise, this is a subframe, so we need to interpolate the pose between the next frame and the last frame.
+                        if next_frame is None:
+                            next_frame = last_frame + 1
+                            context.scene.frame_set(frame=next_frame)
+                            for pose_bone in pose_bones:
+                                location, rotation = _get_pose_bone_location_and_rotation(pose_bone, export_sequence.armature_object, options)
+                                next_frame_bone_poses.append((location, rotation))
+
+                        factor = frame % 1.0
+
+                        for i in range(len(pose_bones)):
+                            last_location, last_rotation = last_frame_bone_poses[i]
+                            next_location, next_rotation = next_frame_bone_poses[i]
+
+                            location = last_location.lerp(next_location, factor)
+                            rotation = last_rotation.slerp(next_rotation, factor)
+
+                            add_key(location, rotation)
+
+                    frame += frame_step
+            case 'SUBFRAME':
+                for _ in range(frame_count):
+                    context.scene.frame_set(frame=int(frame), subframe=frame % 1.0)
+
+                    for pose_bone in pose_bones:
+                        location, rotation = _get_pose_bone_location_and_rotation(pose_bone, export_sequence.armature_object, options)
+                        add_key(location, rotation)
+
+                    frame += frame_step
 
         frame_start_index += frame_count
 

io_scene_psk_psa/psa/config.py

@@ -1,8 +1,6 @@
 import re
 from configparser import ConfigParser
-from typing import Dict
+from typing import Dict, List
-
-from .reader import PsaReader
 
 REMOVE_TRACK_LOCATION = (1 << 0)
 REMOVE_TRACK_ROTATION = (1 << 1)
@@ -28,7 +26,7 @@ def _load_config_file(file_path: str) -> ConfigParser:
     with open(file_path, 'r') as f:
         lines = f.read().split('\n')
 
-    lines = [re.sub(r'^\s*(\w+)\s*$', r'\1=', line) for line in lines]
+    lines = [re.sub(r'^\s*([^=]+)\s*$', r'\1=', line) for line in lines]
 
     contents = '\n'.join(lines)
 
@@ -50,7 +48,7 @@ def _get_bone_flags_from_value(value: str) -> int:
             return 0
 
 
-def read_psa_config(psa_reader: PsaReader, file_path: str) -> PsaConfig:
+def read_psa_config(psa_sequence_names: List[str], file_path: str) -> PsaConfig:
     psa_config = PsaConfig()
 
     config = _load_config_file(file_path)
@@ -62,7 +60,6 @@ def read_psa_config(psa_reader: PsaReader, file_path: str) -> PsaConfig:
 
             # Map the sequence name onto the actual sequence name in the PSA file.
             try:
-                psa_sequence_names = list(psa_reader.sequences.keys())
                 lowercase_sequence_names = [sequence_name.lower() for sequence_name in psa_sequence_names]
                 sequence_name = psa_sequence_names[lowercase_sequence_names.index(sequence_name.lower())]
             except ValueError:

io_scene_psk_psa/psa/export/operators.py

@@ -1,6 +1,5 @@
-import re
 from collections import Counter
-from typing import List, Iterable, Dict, Tuple
+from typing import List, Iterable, Dict, Tuple, cast, Optional
 
 import bpy
 from bpy.props import StringProperty
@@ -8,32 +7,62 @@ from bpy.types import Context, Armature, Action, Object, AnimData, TimelineMarke
 from bpy_extras.io_utils import ExportHelper
 from bpy_types import Operator
 
-from .properties import PSA_PG_export, PSA_PG_export_action_list_item, filter_sequences
+from .properties import PSA_PG_export, PSA_PG_export_action_list_item, filter_sequences, \
+    get_sequences_from_name_and_frame_range
 from ..builder import build_psa, PsaBuildSequence, PsaBuildOptions
 from ..writer import write_psa
-from ...shared.helpers import populate_bone_collection_list, get_nla_strips_in_frame_range
+from ...shared.helpers import populate_bone_collection_list, get_nla_strips_in_frame_range, SemanticVersion
+from ...shared.ui import draw_bone_filter_mode
+
+
+def get_sequences_propnames_from_source(sequence_source: str) -> Optional[Tuple[str, str]]:
+    match sequence_source:
+        case 'ACTIONS':
+            return 'action_list', 'action_list_index'
+        case 'TIMELINE_MARKERS':
+            return 'marker_list', 'marker_list_index'
+        case 'NLA_TRACK_STRIPS':
+            return 'nla_strip_list', 'nla_strip_list_index'
+        case 'ACTIVE_ACTION':
+            return 'active_action_list', 'active_action_list_index'
+        case _:
+            raise ValueError(f'Unhandled sequence source: {sequence_source}')
 
 
 def is_action_for_armature(armature: Armature, action: Action):
     if len(action.fcurves) == 0:
         return False
-    bone_names = set([x.name for x in armature.bones])
+
-    for fcurve in action.fcurves:
+    version = SemanticVersion(bpy.app.version)
-        match = re.match(r'pose\.bones\[\"([^\"]+)\"](\[\"([^\"]+)\"])?', fcurve.data_path)
+
-        if not match:
+    if version < SemanticVersion((4, 4, 0)):
-            continue
+        import re
-        bone_name = match.group(1)
+        bone_names = set([x.name for x in armature.bones])
-        if bone_name in bone_names:
+        for fcurve in action.fcurves:
-            return True
+            match = re.match(r'pose\.bones\[\"([^\"]+)\"](\[\"([^\"]+)\"])?', fcurve.data_path)
+            if not match:
+                continue
+            bone_name = match.group(1)
+            if bone_name in bone_names:
+                return True
+    else:
+        # Look up the armature by ID and check if its data block pointer matches the armature.
+        for slot in filter(lambda x: x.id_root == 'OBJECT', action.slots):
+            # Lop off the 'OB' prefix from the identifier for the lookup.
+            object = bpy.data.objects.get(slot.identifier[2:], None)
+            if object and object.data == armature:
+                return True
+
     return False
 
 
-def update_actions_and_timeline_markers(context: Context, armature: Armature):
+def update_actions_and_timeline_markers(context: Context):
     pg = getattr(context.scene, 'psa_export')
 
     # Clear actions and markers.
     pg.action_list.clear()
     pg.marker_list.clear()
+    pg.active_action_list.clear()
 
     # Get animation data.
     animation_data_object = get_animation_data_object(context)
@@ -42,9 +71,11 @@ def update_actions_and_timeline_markers(context: Context, armature: Armature):
     if animation_data is None:
         return
 
+    active_armature = cast(Armature, context.active_object.data)
+
     # Populate actions list.
     for action in bpy.data.actions:
-        if not is_action_for_armature(armature, action):
+        if not is_action_for_armature(active_armature, action):
             continue
 
         if action.name != '' and not action.name.startswith('#'):
@@ -89,6 +120,21 @@ def update_actions_and_timeline_markers(context: Context, armature: Armature):
             item.frame_start = frame_start
             item.frame_end = frame_end
 
+    # Populate the active action list.
+    for armature_object in context.selected_objects:
+        if armature_object.type != 'ARMATURE':
+            continue
+        action = armature_object.animation_data.action if armature_object.animation_data else None
+        if action is None:
+            continue
+        item = pg.active_action_list.add()
+        item.name = action.name
+        item.armature_object = armature_object
+        item.action = action
+        item.frame_start = int(item.action.frame_range[0])
+        item.frame_end = int(item.action.frame_range[1])
+        item.is_selected = True
+
 
 def get_sequence_fps(context: Context, fps_source: str, fps_custom: float, actions: Iterable[Action]) -> float:
     match fps_source:
@@ -103,6 +149,17 @@ def get_sequence_fps(context: Context, fps_source: str, fps_custom: float, actio
             raise RuntimeError(f'Invalid FPS source "{fps_source}"')
 
 
+def get_sequence_compression_ratio(compression_ratio_source: str, compression_ratio_custom: float, actions: Iterable[Action]) -> float:
+    match compression_ratio_source:
+        case 'ACTION_METADATA':
+            # Get the minimum value of action metadata compression ratio values.
+            return min([action.psa_export.compression_ratio for action in actions])
+        case 'CUSTOM':
+            return compression_ratio_custom
+        case _:
+            raise RuntimeError(f'Invalid compression ratio source "{compression_ratio_source}"')
+
+
 def get_animation_data_object(context: Context) -> Object:
     pg: PSA_PG_export = getattr(context.scene, 'psa_export')
 
@@ -119,19 +176,11 @@ def get_animation_data_object(context: Context) -> Object:
     return animation_data_object
 
 
-def is_bone_filter_mode_item_available(context, identifier):
-    if identifier == 'BONE_COLLECTIONS':
-        armature = context.active_object.data
-        if len(armature.collections) == 0:
-            return False
-    return True
-
-
 def get_timeline_marker_sequence_frame_ranges(animation_data: AnimData, context: Context, marker_names: List[str]) -> Dict:
     # Timeline markers need to be sorted so that we can determine the sequence start and end positions.
     sequence_frame_ranges = dict()
     sorted_timeline_markers = list(sorted(context.scene.timeline_markers, key=lambda x: x.frame))
-    sorted_timeline_marker_names = list(map(lambda x: x.name, sorted_timeline_markers))
+    sorted_timeline_marker_names = [x.name for x in sorted_timeline_markers]
 
     for marker_name in marker_names:
         marker = context.scene.timeline_markers[marker_name]
@@ -144,7 +193,7 @@ def get_timeline_marker_sequence_frame_ranges(animation_data: AnimData, context:
         if next_marker_index < len(sorted_timeline_markers):
             # There is a next marker. Use that next marker's frame position as the last frame of this sequence.
             frame_end = sorted_timeline_markers[next_marker_index].frame
-            nla_strips = get_nla_strips_in_frame_range(animation_data, marker.frame, frame_end)
+            nla_strips = list(get_nla_strips_in_frame_range(animation_data, marker.frame, frame_end))
             if len(nla_strips) > 0:
                 frame_end = min(frame_end, max(map(lambda nla_strip: nla_strip.frame_end, nla_strips)))
                 frame_start = max(frame_start, min(map(lambda nla_strip: nla_strip.frame_start, nla_strips)))
@@ -168,20 +217,6 @@ def get_timeline_marker_sequence_frame_ranges(animation_data: AnimData, context:
     return sequence_frame_ranges
 
 
-def get_sequences_from_name_and_frame_range(name: str, frame_start: int, frame_end: int) -> List[Tuple[str, int, int]]:
-    reversed_pattern = r'(.+)/(.+)'
-    reversed_match = re.match(reversed_pattern, name)
-    if reversed_match:
-        forward_name = reversed_match.group(1)
-        backwards_name = reversed_match.group(2)
-        return [
-            (forward_name, frame_start, frame_end),
-            (backwards_name, frame_end, frame_start)
-        ]
-    else:
-        return [(name, frame_start, frame_end)]
-
-
 def get_sequences_from_action(action: Action) -> List[Tuple[str, int, int]]:
     frame_start = int(action.frame_range[0])
     frame_end = int(action.frame_range[1])
@@ -214,7 +249,7 @@ class PSA_OT_export(Operator, ExportHelper):
     bl_idname = 'psa_export.operator'
     bl_label = 'Export'
     bl_options = {'INTERNAL', 'UNDO'}
-    __doc__ = 'Export actions to PSA'
+    bl_description = 'Export actions to PSA'
     filename_ext = '.psa'
     filter_glob: StringProperty(default='*.psa', options={'HIDDEN'})
     filepath: StringProperty(
@@ -223,7 +258,8 @@ class PSA_OT_export(Operator, ExportHelper):
         maxlen=1024,
         default='')
 
-    def __init__(self):
+    def __init__(self, *args, **kwargs):
+        super().__init__(*args, **kwargs)
         self.armature_object = None
 
     @classmethod
@@ -239,79 +275,106 @@ class PSA_OT_export(Operator, ExportHelper):
         layout = self.layout
         pg = getattr(context.scene, 'psa_export')
 
-        # FPS
+        sequences_header, sequences_panel = layout.panel('Sequences', default_closed=False)
-        layout.prop(pg, 'fps_source', text='FPS')
+        sequences_header.label(text='Sequences', icon='ACTION')
-        if pg.fps_source == 'CUSTOM':
-            layout.prop(pg, 'fps_custom', text='Custom')
 
-        # SOURCE
+        if sequences_panel:
-        layout.prop(pg, 'sequence_source', text='Source')
+            flow = sequences_panel.grid_flow()
-
-        if pg.sequence_source in {'TIMELINE_MARKERS', 'NLA_TRACK_STRIPS'}:
-            # ANIMDATA SOURCE
-            layout.prop(pg, 'should_override_animation_data')
-            if pg.should_override_animation_data:
-                layout.prop(pg, 'animation_data_override', text='')
-
-        if pg.sequence_source == 'NLA_TRACK_STRIPS':
-            flow = layout.grid_flow()
             flow.use_property_split = True
             flow.use_property_decorate = False
-            flow.prop(pg, 'nla_track')
+            flow.prop(pg, 'sequence_source', text='Source')
 
-        # SELECT ALL/NONE
+            if pg.sequence_source in {'TIMELINE_MARKERS', 'NLA_TRACK_STRIPS'}:
-        row = layout.row(align=True)
+                # ANIMDATA SOURCE
-        row.label(text='Select')
+                flow.prop(pg, 'should_override_animation_data')
-        row.operator(PSA_OT_export_actions_select_all.bl_idname, text='All', icon='CHECKBOX_HLT')
+                if pg.should_override_animation_data:
-        row.operator(PSA_OT_export_actions_deselect_all.bl_idname, text='None', icon='CHECKBOX_DEHLT')
+                    flow.prop(pg, 'animation_data_override', text=' ')
 
-        # ACTIONS
+            if pg.sequence_source == 'NLA_TRACK_STRIPS':
-        if pg.sequence_source == 'ACTIONS':
+                flow = sequences_panel.grid_flow()
-            rows = max(3, min(len(pg.action_list), 10))
+                flow.use_property_split = True
-            layout.template_list('PSA_UL_export_sequences', '', pg, 'action_list', pg, 'action_list_index', rows=rows)
+                flow.use_property_decorate = False
-        elif pg.sequence_source == 'TIMELINE_MARKERS':
+                flow.prop(pg, 'nla_track')
-            rows = max(3, min(len(pg.marker_list), 10))
-            layout.template_list('PSA_UL_export_sequences', '', pg, 'marker_list', pg, 'marker_list_index', rows=rows)
-        elif pg.sequence_source == 'NLA_TRACK_STRIPS':
-            rows = max(3, min(len(pg.nla_strip_list), 10))
-            layout.template_list('PSA_UL_export_sequences', '', pg, 'nla_strip_list', pg, 'nla_strip_list_index', rows=rows)
 
-        col = layout.column()
+            # SELECT ALL/NONE
-        col.use_property_split = True
+            row = sequences_panel.row(align=True)
-        col.use_property_decorate = False
+            row.label(text='Select')
-        col.prop(pg, 'sequence_name_prefix')
+            row.operator(PSA_OT_export_actions_select_all.bl_idname, text='All', icon='CHECKBOX_HLT')
-        col.prop(pg, 'sequence_name_suffix')
+            row.operator(PSA_OT_export_actions_deselect_all.bl_idname, text='None', icon='CHECKBOX_DEHLT')
 
-        # Determine if there is going to be a naming conflict and display an error, if so.
+            from .ui import PSA_UL_export_sequences
-        selected_items = [x for x in pg.action_list if x.is_selected]
-        action_names = [x.name for x in selected_items]
-        action_name_counts = Counter(action_names)
-        for action_name, count in action_name_counts.items():
-            if count > 1:
-                layout.label(text=f'Duplicate action: {action_name}', icon='ERROR')
-                break
 
-        layout.separator()
+            propname, active_propname = get_sequences_propnames_from_source(pg.sequence_source)
+            sequences_panel.template_list(PSA_UL_export_sequences.bl_idname, '', pg, propname, pg, active_propname,
+                                          rows=max(3, min(len(getattr(pg, propname)), 10)))
+
+            name_header, name_panel = layout.panel('Name', default_closed=False)
+            name_header.label(text='Name')
+            if name_panel:
+                flow = name_panel.grid_flow()
+                flow.use_property_split = True
+                flow.use_property_decorate = False
+                flow.prop(pg, 'sequence_name_prefix', text='Name Prefix')
+                flow.prop(pg, 'sequence_name_suffix')
+
+                # Determine if there is going to be a naming conflict and display an error, if so.
+                selected_items = [x for x in pg.action_list if x.is_selected]
+                action_names = [x.name for x in selected_items]
+                action_name_counts = Counter(action_names)
+                for action_name, count in action_name_counts.items():
+                    if count > 1:
+                        layout.label(text=f'Duplicate action: {action_name}', icon='ERROR')
+                        break
+
+            sampling_header, sampling_panel = layout.panel('Data Source', default_closed=False)
+            sampling_header.label(text='Sampling')
+            if sampling_panel:
+                flow = sampling_panel.grid_flow()
+                flow.use_property_split = True
+                flow.use_property_decorate = False
+
+                # SAMPLING MODE
+                flow.prop(pg, 'sampling_mode', text='Sampling Mode')
+
+                # FPS
+                col = flow.row(align=True)
+                col.prop(pg, 'fps_source', text='FPS')
+                if pg.fps_source == 'CUSTOM':
+                    col.prop(pg, 'fps_custom', text='')
+
+                # COMPRESSION RATIO
+                col = flow.row(align=True)
+                col.prop(pg, 'compression_ratio_source', text='Compression Ratio')
+                if pg.compression_ratio_source == 'CUSTOM':
+                    col.prop(pg, 'compression_ratio_custom', text='')
 
         # BONES
-        row = layout.row(align=True)
+        bones_header, bones_panel = layout.panel('Bones', default_closed=False)
-        row.prop(pg, 'bone_filter_mode', text='Bones')
+        bones_header.label(text='Bones', icon='BONE_DATA')
+        if bones_panel:
+            row = bones_panel.row(align=True)
 
-        if pg.bone_filter_mode == 'BONE_COLLECTIONS':
+            draw_bone_filter_mode(row, pg)
-            row = layout.row(align=True)
-            row.label(text='Select')
-            row.operator(PSA_OT_export_bone_collections_select_all.bl_idname, text='All', icon='CHECKBOX_HLT')
-            row.operator(PSA_OT_export_bone_collections_deselect_all.bl_idname, text='None', icon='CHECKBOX_DEHLT')
-            rows = max(3, min(len(pg.bone_collection_list), 10))
-            layout.template_list('PSX_UL_bone_collection_list', '', pg, 'bone_collection_list', pg, 'bone_collection_list_index',
-                                 rows=rows)
 
-        layout.prop(pg, 'should_enforce_bone_name_restrictions')
+            if pg.bone_filter_mode == 'BONE_COLLECTIONS':
+                row = bones_panel.row(align=True)
+                row.label(text='Select')
+                row.operator(PSA_OT_export_bone_collections_select_all.bl_idname, text='All', icon='CHECKBOX_HLT')
+                row.operator(PSA_OT_export_bone_collections_deselect_all.bl_idname, text='None', icon='CHECKBOX_DEHLT')
+                rows = max(3, min(len(pg.bone_collection_list), 10))
+                bones_panel.template_list('PSX_UL_bone_collection_list', '', pg, 'bone_collection_list', pg, 'bone_collection_list_index',
+                                     rows=rows)
 
-        layout.separator()
+        # TRANSFORM
+        transform_header, transform_panel = layout.panel('Advanced', default_closed=False)
+        transform_header.label(text='Transform')
 
-        # ROOT MOTION
+        if transform_panel:
-        layout.prop(pg, 'root_motion', text='Root Motion')
+            flow = transform_panel.grid_flow()
+            flow.use_property_split = True
+            flow.use_property_decorate = False
+            flow.prop(pg, 'root_motion', text='Root Motion')
+            flow.prop(pg, 'scale', text='Scale')
 
     @classmethod
     def _check_context(cls, context):
@@ -319,7 +382,19 @@ class PSA_OT_export(Operator, ExportHelper):
             raise RuntimeError('An armature must be selected')
 
         if context.view_layer.objects.active.type != 'ARMATURE':
-            raise RuntimeError('The selected object must be an armature')
+            raise RuntimeError('The active object must be an armature')
+
+        # If we have multiple armatures selected, make sure that they all use the same underlying armature data.
+        armature_objects = [obj for obj in context.selected_objects if obj.type == 'ARMATURE']
+
+        for obj in armature_objects:
+            if obj.data != context.view_layer.objects.active.data:
+                raise RuntimeError(f'All selected armatures must use the same armature data block.\n\n'
+                                   f'\The armature data block for "{obj.name}\" (\'{obj.data.name}\') does not match '
+                                   f'the active armature data block (\'{context.view_layer.objects.active.name}\')')
+
+        if context.scene.is_nla_tweakmode:
+            raise RuntimeError('Cannot export PSA while in NLA tweak mode')
 
     def invoke(self, context, _event):
         try:
@@ -336,7 +411,7 @@ class PSA_OT_export(Operator, ExportHelper):
             # data created before (i.e. if no action was ever assigned to it).
             self.armature_object.animation_data_create()
 
-        update_actions_and_timeline_markers(context, self.armature_object.data)
+        update_actions_and_timeline_markers(context)
 
         populate_bone_collection_list(self.armature_object, pg.bone_collection_list)
 
@@ -364,53 +439,68 @@ class PSA_OT_export(Operator, ExportHelper):
 
         export_sequences: List[PsaBuildSequence] = []
 
-        if pg.sequence_source == 'ACTIONS':
+        selected_armature_objects = [obj for obj in context.selected_objects if obj.type == 'ARMATURE']
-            for action_item in filter(lambda x: x.is_selected, pg.action_list):
+
-                if len(action_item.action.fcurves) == 0:
+        match pg.sequence_source:
-                    continue
+            case 'ACTIONS':
-                export_sequence = PsaBuildSequence()
+                for action_item in filter(lambda x: x.is_selected, pg.action_list):
-                export_sequence.nla_state.action = action_item.action
+                    if len(action_item.action.fcurves) == 0:
-                export_sequence.name = action_item.name
+                        continue
-                export_sequence.nla_state.frame_start = action_item.frame_start
+                    export_sequence = PsaBuildSequence(context.active_object, animation_data)
-                export_sequence.nla_state.frame_end = action_item.frame_end
+                    export_sequence.name = action_item.name
-                export_sequence.fps = get_sequence_fps(context, pg.fps_source, pg.fps_custom, [action_item.action])
+                    export_sequence.nla_state.action = action_item.action
-                export_sequence.compression_ratio = action_item.action.psa_export.compression_ratio
+                    export_sequence.nla_state.frame_start = action_item.frame_start
-                export_sequence.key_quota = action_item.action.psa_export.key_quota
+                    export_sequence.nla_state.frame_end = action_item.frame_end
-                export_sequences.append(export_sequence)
+                    export_sequence.fps = get_sequence_fps(context, pg.fps_source, pg.fps_custom, [action_item.action])
-        elif pg.sequence_source == 'TIMELINE_MARKERS':
+                    export_sequence.compression_ratio = get_sequence_compression_ratio(pg.compression_ratio_source, pg.compression_ratio_custom, [action_item.action])
-            for marker_item in filter(lambda x: x.is_selected, pg.marker_list):
+                    export_sequence.key_quota = action_item.action.psa_export.key_quota
-                export_sequence = PsaBuildSequence()
+                    export_sequences.append(export_sequence)
-                export_sequence.name = marker_item.name
+            case 'TIMELINE_MARKERS':
-                export_sequence.nla_state.action = None
+                for marker_item in filter(lambda x: x.is_selected, pg.marker_list):
-                export_sequence.nla_state.frame_start = marker_item.frame_start
+                    export_sequence = PsaBuildSequence(context.active_object, animation_data)
-                export_sequence.nla_state.frame_end = marker_item.frame_end
+                    export_sequence.name = marker_item.name
-                nla_strips_actions = set(
+                    export_sequence.nla_state.frame_start = marker_item.frame_start
-                    map(lambda x: x.action, get_nla_strips_in_frame_range(animation_data, marker_item.frame_start, marker_item.frame_end)))
+                    export_sequence.nla_state.frame_end = marker_item.frame_end
-                export_sequence.fps = get_sequence_fps(context, pg.fps_source, pg.fps_custom, nla_strips_actions)
+                    nla_strips_actions = set(
-                export_sequences.append(export_sequence)
+                        map(lambda x: x.action, get_nla_strips_in_frame_range(animation_data, marker_item.frame_start, marker_item.frame_end)))
-        elif pg.sequence_source == 'NLA_TRACK_STRIPS':
+                    export_sequence.fps = get_sequence_fps(context, pg.fps_source, pg.fps_custom, nla_strips_actions)
-            for nla_strip_item in filter(lambda x: x.is_selected, pg.nla_strip_list):
+                    export_sequence.compression_ratio = get_sequence_compression_ratio(pg.compression_ratio_source, pg.compression_ratio_custom, nla_strips_actions)
-                export_sequence = PsaBuildSequence()
+                    export_sequences.append(export_sequence)
-                export_sequence.name = nla_strip_item.name
+            case 'NLA_TRACK_STRIPS':
-                export_sequence.nla_state.action = None
+                for nla_strip_item in filter(lambda x: x.is_selected, pg.nla_strip_list):
-                export_sequence.nla_state.frame_start = nla_strip_item.frame_start
+                    export_sequence = PsaBuildSequence(context.active_object, animation_data)
-                export_sequence.nla_state.frame_end = nla_strip_item.frame_end
+                    export_sequence.name = nla_strip_item.name
-                export_sequence.fps = get_sequence_fps(context, pg.fps_source, pg.fps_custom, [nla_strip_item.action])
+                    export_sequence.nla_state.frame_start = nla_strip_item.frame_start
-                export_sequence.compression_ratio = nla_strip_item.action.psa_export.compression_ratio
+                    export_sequence.nla_state.frame_end = nla_strip_item.frame_end
-                export_sequence.key_quota = nla_strip_item.action.psa_export.key_quota
+                    export_sequence.fps = get_sequence_fps(context, pg.fps_source, pg.fps_custom, [nla_strip_item.action])
-                export_sequences.append(export_sequence)
+                    export_sequence.compression_ratio = get_sequence_compression_ratio(pg.compression_ratio_source, pg.compression_ratio_custom, [nla_strip_item.action])
-        else:
+                    export_sequence.key_quota = nla_strip_item.action.psa_export.key_quota
-            raise ValueError(f'Unhandled sequence source: {pg.sequence_source}')
+                    export_sequences.append(export_sequence)
+            case 'ACTIVE_ACTION':
+                for active_action_item in filter(lambda x: x.is_selected, pg.active_action_list):
+                    export_sequence = PsaBuildSequence(active_action_item.armature_object, active_action_item.armature_object.animation_data)
+                    action = active_action_item.action
+                    export_sequence.name = action.name
+                    export_sequence.nla_state.action = action
+                    export_sequence.nla_state.frame_start = int(action.frame_range[0])
+                    export_sequence.nla_state.frame_end = int(action.frame_range[1])
+                    export_sequence.fps = get_sequence_fps(context, pg.fps_source, pg.fps_custom, [action])
+                    export_sequence.compression_ratio = get_sequence_compression_ratio(pg.compression_ratio_source, pg.compression_ratio_custom, [action])
+                    export_sequence.key_quota = action.psa_export.key_quota
+                    export_sequences.append(export_sequence)
+            case _:
+                raise ValueError(f'Unhandled sequence source: {pg.sequence_source}')
 
         options = PsaBuildOptions()
         options.animation_data = animation_data
         options.sequences = export_sequences
         options.bone_filter_mode = pg.bone_filter_mode
         options.bone_collection_indices = [x.index for x in pg.bone_collection_list if x.is_selected]
-        options.should_ignore_bone_name_restrictions = pg.should_enforce_bone_name_restrictions
         options.sequence_name_prefix = pg.sequence_name_prefix
         options.sequence_name_suffix = pg.sequence_name_suffix
         options.root_motion = pg.root_motion
+        options.scale = pg.scale
+        options.sampling_mode = pg.sampling_mode
 
         try:
             psa = build_psa(context, options)
@@ -433,13 +523,17 @@ class PSA_OT_export_actions_select_all(Operator):
     @classmethod
     def get_item_list(cls, context):
         pg = context.scene.psa_export
-        if pg.sequence_source == 'ACTIONS':
+        match pg.sequence_source:
-            return pg.action_list
+            case 'ACTIONS':
-        elif pg.sequence_source == 'TIMELINE_MARKERS':
+                return pg.action_list
-            return pg.marker_list
+            case 'TIMELINE_MARKERS':
-        elif pg.sequence_source == 'NLA_TRACK_STRIPS':
+                return pg.marker_list
-            return pg.nla_strip_list
+            case 'NLA_TRACK_STRIPS':
-        return None
+                return pg.nla_strip_list
+            case 'ACTIVE_ACTION':
+                return pg.active_action_list
+            case _:
+                return None
 
     @classmethod
     def poll(cls, context):
@@ -466,13 +560,17 @@ class PSA_OT_export_actions_deselect_all(Operator):
     @classmethod
     def get_item_list(cls, context):
         pg = context.scene.psa_export
-        if pg.sequence_source == 'ACTIONS':
+        match pg.sequence_source:
-            return pg.action_list
+            case 'ACTIONS':
-        elif pg.sequence_source == 'TIMELINE_MARKERS':
+                return pg.action_list
-            return pg.marker_list
+            case 'TIMELINE_MARKERS':
-        elif pg.sequence_source == 'NLA_TRACK_STRIPS':
+                return pg.marker_list
-            return pg.nla_strip_list
+            case 'NLA_TRACK_STRIPS':
-        return None
+                return pg.nla_strip_list
+            case 'ACTIVE_ACTION':
+                return pg.active_action_list
+            case _:
+                return None
 
     @classmethod
     def poll(cls, context):

io_scene_psk_psa/psa/export/properties.py

@@ -1,12 +1,13 @@
 import re
 import sys
 from fnmatch import fnmatch
-from typing import List, Optional
+from typing import List, Optional, Tuple
 
 from bpy.props import BoolProperty, PointerProperty, EnumProperty, FloatProperty, CollectionProperty, IntProperty, \
     StringProperty
 from bpy.types import PropertyGroup, Object, Action, AnimData, Context
 
+from ...shared.data import bone_filter_mode_items
 from ...shared.types import PSX_PG_bone_collection_list_item
 
 
@@ -26,6 +27,15 @@ class PSA_PG_export_action_list_item(PropertyGroup):
     is_pose_marker: BoolProperty(options={'HIDDEN'})
 
 
+class PSA_PG_export_active_action_list_item(PropertyGroup):
+    action: PointerProperty(type=Action)
+    name: StringProperty()
+    armature_object: PointerProperty(type=Object)
+    is_selected: BoolProperty(default=True)
+    frame_start: IntProperty(options={'HIDDEN'})
+    frame_end: IntProperty(options={'HIDDEN'})
+
+
 class PSA_PG_export_timeline_markers(PropertyGroup):  # TODO: rename this to singular
     marker_index: IntProperty()
     name: StringProperty()
@@ -42,6 +52,20 @@ class PSA_PG_export_nla_strip_list_item(PropertyGroup):
     is_selected: BoolProperty(default=True)
 
 
+def get_sequences_from_name_and_frame_range(name: str, frame_start: int, frame_end: int) -> List[Tuple[str, int, int]]:
+    reversed_pattern = r'(.+)/(.+)'
+    reversed_match = re.match(reversed_pattern, name)
+    if reversed_match:
+        forward_name = reversed_match.group(1)
+        backwards_name = reversed_match.group(2)
+        return [
+            (forward_name, frame_start, frame_end),
+            (backwards_name, frame_end, frame_start)
+        ]
+    else:
+        return [(name, frame_start, frame_end)]
+
+
 def nla_track_update_cb(self: 'PSA_PG_export', context: Context) -> None:
     self.nla_strip_list.clear()
     match = re.match(r'^(\d+).+$', self.nla_track)
@@ -52,11 +76,12 @@ def nla_track_update_cb(self: 'PSA_PG_export', context: Context) -> None:
             return
         nla_track = animation_data.nla_tracks[self.nla_track_index]
         for nla_strip in nla_track.strips:
-            strip: PSA_PG_export_nla_strip_list_item = self.nla_strip_list.add()
+            for sequence_name, frame_start, frame_end in get_sequences_from_name_and_frame_range(nla_strip.name, nla_strip.frame_start, nla_strip.frame_end):
-            strip.action = nla_strip.action
+                strip: PSA_PG_export_nla_strip_list_item = self.nla_strip_list.add()
-            strip.name = nla_strip.name
+                strip.action = nla_strip.action
-            strip.frame_start = nla_strip.frame_start
+                strip.name = sequence_name
-            strip.frame_end = nla_strip.frame_end
+                strip.frame_start = frame_start
+                strip.frame_end = frame_end
 
 
 def get_animation_data(pg: 'PSA_PG_export', context: Context) -> Optional[AnimData]:
@@ -69,10 +94,9 @@ def get_animation_data(pg: 'PSA_PG_export', context: Context) -> Optional[AnimDa
 def nla_track_search_cb(self, context: Context, edit_text: str):
     pg = getattr(context.scene, 'psa_export')
     animation_data = get_animation_data(pg, context)
-    if animation_data is None:
+    if animation_data is not None:
-        return
+        for index, nla_track in enumerate(animation_data.nla_tracks):
-    for index, nla_track in enumerate(animation_data.nla_tracks):
+            yield f'{index} - {nla_track.name}'
-        yield f'{index} - {nla_track.name}'
 
 
 def animation_data_override_update_cb(self: 'PSA_PG_export', context: Context):
@@ -108,7 +132,8 @@ class PSA_PG_export(PropertyGroup):
         items=(
             ('ACTIONS', 'Actions', 'Sequences will be exported using actions', 'ACTION', 0),
             ('TIMELINE_MARKERS', 'Timeline Markers', 'Sequences are delineated by scene timeline markers', 'MARKER_HLT', 1),
-            ('NLA_TRACK_STRIPS', 'NLA Track Strips', 'Sequences are delineated by the start & end times of strips on the selected NLA track', 'NLA', 2)
+            ('NLA_TRACK_STRIPS', 'NLA Track Strips', 'Sequences are delineated by the start & end times of strips on the selected NLA track', 'NLA', 2),
+            ('ACTIVE_ACTION', 'Active Action', 'The active action will be exported for each selected armature', 'ACTION', 3),
         )
     )
     nla_track: StringProperty(
@@ -125,36 +150,38 @@ class PSA_PG_export(PropertyGroup):
         description='',
         items=(
             ('SCENE', 'Scene', '', 'SCENE_DATA', 0),
-            ('ACTION_METADATA', 'Action Metadata', 'The frame rate will be determined by action\'s FPS property found in the PSA Export panel.\n\nIf the Sequence Source is Timeline Markers, the lowest value of all contributing actions will be used', 'PROPERTIES', 1),
+            ('ACTION_METADATA', 'Action Metadata', 'The frame rate will be determined by action\'s FPS property found in the PSA Export panel.\n\nIf the Sequence Source is Timeline Markers, the lowest value of all contributing actions will be used', 'ACTION', 1),
             ('CUSTOM', 'Custom', '', 2)
         )
     )
     fps_custom: FloatProperty(default=30.0, min=sys.float_info.epsilon, soft_min=1.0, options=empty_set, step=100,
                               soft_max=60.0)
+    compression_ratio_source: EnumProperty(
+        name='Compression Ratio Source',
+        options=empty_set,
+        description='',
+        items=(
+            ('ACTION_METADATA', 'Action Metadata', 'The compression ratio will be determined by action\'s Compression Ratio property found in the PSA Export panel.\n\nIf the Sequence Source is Timeline Markers, the lowest value of all contributing actions will be used', 'ACTION', 1),
+            ('CUSTOM', 'Custom', '', 2)
+        )
+    )
+    compression_ratio_custom: FloatProperty(default=1.0, min=0.0, max=1.0, subtype='FACTOR', description='The key sampling ratio of the exported sequence.\n\nA compression ratio of 1.0 will export all frames, while a compression ratio of 0.5 will export half of the frames')
     action_list: CollectionProperty(type=PSA_PG_export_action_list_item)
     action_list_index: IntProperty(default=0)
     marker_list: CollectionProperty(type=PSA_PG_export_timeline_markers)
     marker_list_index: IntProperty(default=0)
     nla_strip_list: CollectionProperty(type=PSA_PG_export_nla_strip_list_item)
     nla_strip_list_index: IntProperty(default=0)
+    active_action_list: CollectionProperty(type=PSA_PG_export_active_action_list_item)
+    active_action_list_index: IntProperty(default=0)
     bone_filter_mode: EnumProperty(
         name='Bone Filter',
         options=empty_set,
         description='',
-        items=(
+        items=bone_filter_mode_items,
-            ('ALL', 'All', 'All bones will be exported.'),
-            ('BONE_COLLECTIONS', 'Bone Collections', 'Only bones belonging to the selected bone collections and their '
-             'ancestors will be exported.'),
-        )
     )
     bone_collection_list: CollectionProperty(type=PSX_PG_bone_collection_list_item)
     bone_collection_list_index: IntProperty(default=0, name='', description='')
-    should_enforce_bone_name_restrictions: BoolProperty(
-        default=False,
-        name='Enforce Bone Name Restrictions',
-        description='Bone names restrictions will be enforced. Note that bone names without properly formatted names '
-                    'may not be able to be referenced in-engine'
-    )
     sequence_name_prefix: StringProperty(name='Prefix', options=empty_set)
     sequence_name_suffix: StringProperty(name='Suffix', options=empty_set)
     sequence_filter_name: StringProperty(
@@ -183,6 +210,23 @@ class PSA_PG_export(PropertyGroup):
         name='Show Reversed',
         description='Show reversed sequences'
     )
+    scale: FloatProperty(
+        name='Scale',
+        default=1.0,
+        description='Scale factor to apply to the bone translations. Use this if you are exporting animations for a scaled PSK mesh',
+        min=0.0,
+        soft_max=100.0
+    )
+    sampling_mode: EnumProperty(
+        name='Sampling Mode',
+        options=empty_set,
+        description='The method by which frames are sampled',
+        items=(
+            ('INTERPOLATED', 'Interpolated', 'Sampling is performed by interpolating the evaluated bone poses from the adjacent whole frames.', 'INTERPOLATED', 0),
+            ('SUBFRAME', 'Subframe', 'Sampling is performed by evaluating the bone poses at the subframe time.\n\nNot recommended unless you are also animating with subframes enabled.', 'SUBFRAME', 1),
+        ),
+        default='INTERPOLATED'
+    )
 
 
 def filter_sequences(pg: PSA_PG_export, sequences) -> List[int]:
@@ -222,5 +266,6 @@ classes = (
     PSA_PG_export_action_list_item,
     PSA_PG_export_timeline_markers,
     PSA_PG_export_nla_strip_list_item,
+    PSA_PG_export_active_action_list_item,
     PSA_PG_export,
 )

io_scene_psk_psa/psa/export/ui.py

@@ -1,4 +1,4 @@
-from typing import cast
+import typing
 
 from bpy.types import UIList
 
@@ -6,14 +6,16 @@ from .properties import PSA_PG_export_action_list_item, filter_sequences
 
 
 class PSA_UL_export_sequences(UIList):
+    bl_idname = 'PSA_UL_export_sequences'
 
-    def __init__(self):
+    def __init__(self, *args, **kwargs):
-        super(PSA_UL_export_sequences, self).__init__()
+        super(PSA_UL_export_sequences, self).__init__(*args, **kwargs)
         # Show the filtering options by default.
         self.use_filter_show = True
 
     def draw_item(self, context, layout, data, item, icon, active_data, active_propname, index):
-        item = cast(PSA_PG_export_action_list_item, item)
+        item = typing.cast(PSA_PG_export_action_list_item, item)
+
         is_pose_marker = hasattr(item, 'is_pose_marker') and item.is_pose_marker
         layout.prop(item, 'is_selected', icon_only=True, text=item.name)
         if hasattr(item, 'action') and item.action is not None and item.action.asset_data is not None:
@@ -26,6 +28,9 @@ class PSA_UL_export_sequences(UIList):
         if is_pose_marker:
             row.label(text=item.action.name, icon='PMARKER')
 
+        if hasattr(item, 'armature_object') and item.armature_object is not None:
+            row.label(text=item.armature_object.name, icon='ARMATURE_DATA')
+
     def draw_filter(self, context, layout):
         pg = getattr(context.scene, 'psa_export')
         row = layout.row()

io_scene_psk_psa/psa/import_/operators.py

@@ -1,8 +1,9 @@
 import os
 from pathlib import Path
+from typing import List
 
-from bpy.props import StringProperty
+from bpy.props import StringProperty, CollectionProperty
-from bpy.types import Operator, Event, Context, FileHandler
+from bpy.types import Operator, Event, Context, FileHandler, OperatorFileListElement, Object
 from bpy_extras.io_utils import ImportHelper
 
 from .properties import get_visible_sequences
@@ -108,11 +109,98 @@ def load_psa_file(context, filepath: str):
         pg.psa_error = str(e)
 
 
-
 def on_psa_file_path_updated(cls, context):
     load_psa_file(context, cls.filepath)
 
 
+class PSA_OT_import_multiple(Operator):
+    bl_idname = 'psa_import.import_multiple'
+    bl_label = 'Import PSA'
+    bl_description = 'Import multiple PSA files'
+    bl_options = {'INTERNAL', 'UNDO'}
+
+    directory: StringProperty(subtype='FILE_PATH', options={'SKIP_SAVE', 'HIDDEN'})
+    files: CollectionProperty(type=OperatorFileListElement, options={'SKIP_SAVE', 'HIDDEN'})
+
+
+    def execute(self, context):
+        pg = getattr(context.scene, 'psa_import')
+        warnings = []
+
+        for file in self.files:
+            psa_path = os.path.join(self.directory, file.name)
+            psa_reader = PsaReader(psa_path)
+            sequence_names = list(psa_reader.sequences.keys())
+
+            result = _import_psa(context, pg, psa_path, sequence_names, context.view_layer.objects.active)
+            result.warnings.extend(warnings)
+
+        if len(result.warnings) > 0:
+            message = f'Imported {len(sequence_names)} action(s) with {len(result.warnings)} warning(s)\n'
+            self.report({'INFO'}, message)
+            for warning in result.warnings:
+                self.report({'WARNING'}, warning)
+
+        self.report({'INFO'}, f'Imported {len(sequence_names)} action(s)')
+
+        return {'FINISHED'}
+
+    def invoke(self, context: Context, event):
+        # Make sure the selected object is an armature.
+        active_object = context.view_layer.objects.active
+        if active_object is None or active_object.type != 'ARMATURE':
+            self.report({'ERROR_INVALID_CONTEXT'}, 'The active object must be an armature')
+            return {'CANCELLED'}
+
+        # Show the import operator properties in a pop-up dialog (do not use the file selector).
+        context.window_manager.invoke_props_dialog(self)
+        return {'RUNNING_MODAL'}
+
+    def draw(self, context):
+        layout = self.layout
+        pg = getattr(context.scene, 'psa_import')
+        draw_psa_import_options_no_panels(layout, pg)
+
+
+def _import_psa(context,
+                pg,
+                filepath: str,
+                sequence_names: List[str],
+                armature_object: Object
+                ):
+    options = PsaImportOptions()
+    options.sequence_names = sequence_names
+    options.should_use_fake_user = pg.should_use_fake_user
+    options.should_stash = pg.should_stash
+    options.action_name_prefix = pg.action_name_prefix if pg.should_use_action_name_prefix else ''
+    options.should_overwrite = pg.should_overwrite
+    options.should_write_metadata = pg.should_write_metadata
+    options.should_write_keyframes = pg.should_write_keyframes
+    options.should_convert_to_samples = pg.should_convert_to_samples
+    options.bone_mapping_mode = pg.bone_mapping_mode
+    options.fps_source = pg.fps_source
+    options.fps_custom = pg.fps_custom
+    options.translation_scale = pg.translation_scale
+
+    warnings = []
+
+    if options.should_use_config_file:
+        # Read the PSA config file if it exists.
+        config_path = Path(filepath).with_suffix('.config')
+        if config_path.exists():
+            try:
+                options.psa_config = read_psa_config(sequence_names, str(config_path))
+            except Exception as e:
+                warnings.append(f'Failed to read PSA config file: {e}')
+
+    psa_reader = PsaReader(filepath)
+
+    result = import_psa(context, psa_reader, armature_object, options)
+    result.warnings.extend(warnings)
+
+    return result
+
+
 class PSA_OT_import(Operator, ImportHelper):
     bl_idname = 'psa_import.import'
     bl_label = 'Import'
@@ -138,36 +226,13 @@ class PSA_OT_import(Operator, ImportHelper):
 
     def execute(self, context):
         pg = getattr(context.scene, 'psa_import')
-        psa_reader = PsaReader(self.filepath)
         sequence_names = [x.action_name for x in pg.sequence_list if x.is_selected]
 
         if len(sequence_names) == 0:
             self.report({'ERROR_INVALID_CONTEXT'}, 'No sequences selected')
             return {'CANCELLED'}
 
-        options = PsaImportOptions()
+        result = _import_psa(context, pg, self.filepath, sequence_names, context.view_layer.objects.active)
-        options.sequence_names = sequence_names
-        options.should_use_fake_user = pg.should_use_fake_user
-        options.should_stash = pg.should_stash
-        options.action_name_prefix = pg.action_name_prefix if pg.should_use_action_name_prefix else ''
-        options.should_overwrite = pg.should_overwrite
-        options.should_write_metadata = pg.should_write_metadata
-        options.should_write_keyframes = pg.should_write_keyframes
-        options.should_convert_to_samples = pg.should_convert_to_samples
-        options.bone_mapping_mode = pg.bone_mapping_mode
-        options.fps_source = pg.fps_source
-        options.fps_custom = pg.fps_custom
-
-        if options.should_use_config_file:
-            # Read the PSA config file if it exists.
-            config_path = Path(self.filepath).with_suffix('.config')
-            if config_path.exists():
-                try:
-                    options.psa_config = read_psa_config(psa_reader, str(config_path))
-                except Exception as e:
-                    self.report({'WARNING'}, f'Failed to read PSA config file: {e}')
-
-        result = import_psa(context, psa_reader, context.view_layer.objects.active, options)
 
         if len(result.warnings) > 0:
             message = f'Imported {len(sequence_names)} action(s) with {len(result.warnings)} warning(s)\n'
@@ -249,6 +314,11 @@ class PSA_OT_import(Operator, ImportHelper):
             col.use_property_decorate = False
             col.prop(pg, 'bone_mapping_mode')
 
+            col = advanced_panel.column()
+            col.use_property_split = True
+            col.use_property_decorate = False
+            col.prop(pg, 'translation_scale', text='Translation Scale')
+
             col = advanced_panel.column(heading='Options')
             col.use_property_split = True
             col.use_property_decorate = False
@@ -257,10 +327,49 @@ class PSA_OT_import(Operator, ImportHelper):
             col.prop(pg, 'should_use_config_file')
 
 
+def draw_psa_import_options_no_panels(layout, pg):
+    col = layout.column(heading='Sequences')
+    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')
+    col.use_property_split = True
+    col.use_property_decorate = False
+    col.prop(pg, 'should_write_keyframes')
+    col.prop(pg, 'should_write_metadata')
+
+    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')
+
+    col = layout.column()
+    col.use_property_split = True
+    col.use_property_decorate = False
+    col.prop(pg, 'bone_mapping_mode')
+    col.prop(pg, 'translation_scale')
+
+    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')
+
+
 class PSA_FH_import(FileHandler):
     bl_idname = 'PSA_FH_import'
     bl_label = 'File handler for Unreal PSA import'
-    bl_import_operator = 'psa_import.import'
+    bl_import_operator = 'psa_import.import_multiple'
+    bl_export_operator = 'psa_export.export'
     bl_file_extensions = '.psa'
 
     @classmethod
@@ -273,5 +382,6 @@ classes = (
     PSA_OT_import_sequences_deselect_all,
     PSA_OT_import_sequences_from_text,
     PSA_OT_import,
+    PSA_OT_import_multiple,
     PSA_FH_import,
 )

io_scene_psk_psa/psa/import_/properties.py

@@ -103,6 +103,11 @@ class PSA_PG_import(PropertyGroup):
         soft_max=1.0,
         step=0.0625,
     )
+    translation_scale: FloatProperty(
+        name='Translation Scale',
+        default=1.0,
+        description='Scale factor for bone translation values. Use this when the scale of the armature does not match the PSA file'
+    )
 
 
 def filter_sequences(pg: PSA_PG_import, sequences) -> List[int]:

io_scene_psk_psa/psa/importer.py

@@ -24,6 +24,7 @@ class PsaImportOptions(object):
         self.bone_mapping_mode = 'CASE_INSENSITIVE'
         self.fps_source = 'SEQUENCE'
         self.fps_custom: float = 30.0
+        self.translation_scale: float = 1.0
         self.should_use_config_file = True
         self.psa_config: PsaConfig = PsaConfig()
 
@@ -88,6 +89,7 @@ def _get_sample_frame_times(source_frame_count: int, frame_step: float) -> typin
         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.
@@ -271,6 +273,10 @@ def import_psa(context: Context, psa_reader: PsaReader, armature_object: Object,
             # Read the sequence data matrix from the PSA.
             sequence_data_matrix = psa_reader.read_sequence_data_matrix(sequence_name)
 
+            if options.translation_scale != 1.0:
+                # Scale the translation data.
+                sequence_data_matrix[:, :, 4:] *= options.translation_scale
+
             # Convert the sequence's data from world-space to local-space.
             for bone_index, import_bone in enumerate(import_bones):
                 if import_bone is None:

io_scene_psk_psa/psk/builder.py

@@ -1,18 +1,20 @@
+import typing
 from typing import Optional
 
 import bmesh
-import bpy
 import numpy as np
-from bpy.types import Armature, Material
+from bpy.types import Material, Collection, Context
+from mathutils import Matrix, Vector
 
 from .data import *
 from .properties import triangle_type_and_bit_flags_to_poly_flags
+from ..shared.dfs import dfs_collection_objects, dfs_view_layer_objects, DfsObject
 from ..shared.helpers import *
 
 
 class PskInputObjects(object):
     def __init__(self):
-        self.mesh_objects = []
+        self.mesh_objects: List[DfsObject] = []
         self.armature_object: Optional[Object] = None
 
 
@@ -20,30 +22,57 @@ class PskBuildOptions(object):
     def __init__(self):
         self.bone_filter_mode = 'ALL'
         self.bone_collection_indices: List[int] = []
-        self.use_raw_mesh_data = True
+        self.object_eval_state = 'EVALUATED'
         self.materials: List[Material] = []
-        self.should_enforce_bone_name_restrictions = False
+        self.scale = 1.0
+        self.export_space = 'WORLD'
+        self.forward_axis = 'X'
+        self.up_axis = 'Z'
 
 
-def get_psk_input_objects(context) -> PskInputObjects:
+def get_vector_from_axis_identifier(axis_identifier: str) -> Vector:
-    input_objects = PskInputObjects()
+    match axis_identifier:
-    for selected_object in context.view_layer.objects.selected:
+        case 'X':
-        if selected_object.type == 'MESH':
+            return Vector((1.0, 0.0, 0.0))
-            input_objects.mesh_objects.append(selected_object)
+        case 'Y':
+            return Vector((0.0, 1.0, 0.0))
+        case 'Z':
+            return Vector((0.0, 0.0, 1.0))
+        case '-X':
+            return Vector((-1.0, 0.0, 0.0))
+        case '-Y':
+            return Vector((0.0, -1.0, 0.0))
+        case '-Z':
+            return Vector((0.0, 0.0, -1.0))
 
-    if len(input_objects.mesh_objects) == 0:
-        raise RuntimeError('At least one mesh must be selected')
 
-    for mesh_object in input_objects.mesh_objects:
+def get_coordinate_system_transform(forward_axis: str = 'X', up_axis: str = 'Z') -> Matrix:
-        if len(mesh_object.data.materials) == 0:
+    forward = get_vector_from_axis_identifier(forward_axis)
-            raise RuntimeError(f'Mesh "{mesh_object.name}" must have at least one material')
+    up = get_vector_from_axis_identifier(up_axis)
+    left = up.cross(forward)
+    return Matrix((
+        (forward.x, forward.y, forward.z, 0.0),
+        (left.x, left.y, left.z, 0.0),
+        (up.x, up.y, up.z, 0.0),
+        (0.0, 0.0, 0.0, 1.0)
+    )).inverted()
 
-    # Ensure that there are either no armature modifiers (static mesh)
+
-    # or that there is exactly one armature modifier object shared between
+def get_mesh_objects_for_collection(collection: Collection) -> Iterable[DfsObject]:
-    # all selected meshes
+    return filter(lambda x: x.obj.type == 'MESH', dfs_collection_objects(collection))
+
+
+def get_mesh_objects_for_context(context: Context) -> Iterable[DfsObject]:
+    for dfs_object in dfs_view_layer_objects(context.view_layer):
+        if dfs_object.obj.type == 'MESH' and dfs_object.is_selected:
+            yield dfs_object
+
+
+def get_armature_for_mesh_objects(mesh_objects: Iterable[Object]) -> Optional[Object]:
+    # Ensure that there are either no armature modifiers (static mesh) or that there is exactly one armature modifier
+    # object shared between all meshes.
     armature_modifier_objects = set()
-
+    for mesh_object in mesh_objects:
-    for mesh_object in input_objects.mesh_objects:
         modifiers = [x for x in mesh_object.modifiers if x.type == 'ARMATURE']
         if len(modifiers) == 0:
             continue
@@ -53,27 +82,69 @@ def get_psk_input_objects(context) -> PskInputObjects:
 
     if len(armature_modifier_objects) > 1:
         armature_modifier_names = [x.name for x in armature_modifier_objects]
-        raise RuntimeError(f'All selected meshes must have the same armature modifier, encountered {len(armature_modifier_names)} ({", ".join(armature_modifier_names)})')
+        raise RuntimeError(
+            f'All meshes must have the same armature modifier, encountered {len(armature_modifier_names)} ({", ".join(armature_modifier_names)})')
     elif len(armature_modifier_objects) == 1:
-        input_objects.armature_object = list(armature_modifier_objects)[0]
+        return list(armature_modifier_objects)[0]
+    else:
+        return None
+
+
+def _get_psk_input_objects(mesh_objects: Iterable[DfsObject]) -> PskInputObjects:
+    mesh_objects = list(mesh_objects)
+    if len(mesh_objects) == 0:
+        raise RuntimeError('At least one mesh must be selected')
+
+    input_objects = PskInputObjects()
+    input_objects.mesh_objects = mesh_objects
+    input_objects.armature_object = get_armature_for_mesh_objects([x.obj for x in mesh_objects])
 
     return input_objects
 
 
+def get_psk_input_objects_for_context(context: Context) -> PskInputObjects:
+    mesh_objects = list(get_mesh_objects_for_context(context))
+    return _get_psk_input_objects(mesh_objects)
+
+
+def get_psk_input_objects_for_collection(collection: Collection, should_exclude_hidden_meshes: bool = True) -> PskInputObjects:
+    mesh_objects = get_mesh_objects_for_collection(collection)
+    if should_exclude_hidden_meshes:
+        mesh_objects = filter(lambda x: x.is_visible, mesh_objects)
+    return _get_psk_input_objects(mesh_objects)
+
+
 class PskBuildResult(object):
     def __init__(self):
         self.psk = None
         self.warnings: List[str] = []
 
 
-def build_psk(context, options: PskBuildOptions) -> PskBuildResult:
+def build_psk(context, input_objects: PskInputObjects, options: PskBuildOptions) -> PskBuildResult:
-    input_objects = get_psk_input_objects(context)
     armature_object: bpy.types.Object = input_objects.armature_object
 
     result = PskBuildResult()
     psk = Psk()
     bones = []
 
+    def get_export_space_matrix():
+        match options.export_space:
+            case 'WORLD':
+                return Matrix.Identity(4)
+            case 'ARMATURE':
+                if armature_object is not None:
+                    return armature_object.matrix_world.inverted()
+                else:
+                    return Matrix.Identity(4)
+            case _:
+                raise ValueError(f'Invalid export space: {options.export_space}')
+
+    coordinate_system_matrix = get_coordinate_system_transform(options.forward_axis, options.up_axis)
+    coordinate_system_default_rotation = coordinate_system_matrix.to_quaternion()
+
+    export_space_matrix = get_export_space_matrix()  # TODO: maybe neutralize the scale here?
+    scale_matrix = coordinate_system_matrix @ Matrix.Scale(options.scale, 4)
+
     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.
@@ -83,17 +154,13 @@ def build_psk(context, options: PskBuildOptions) -> PskBuildResult:
         psk_bone.children_count = 0
         psk_bone.parent_index = 0
         psk_bone.location = Vector3.zero()
-        psk_bone.rotation = Quaternion.identity()
+        psk_bone.rotation = 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)
         armature_data = typing.cast(Armature, armature_object.data)
         bones = [armature_data.bones[bone_name] for bone_name in bone_names]
 
-        # Check that all bone names are valid.
-        if options.should_enforce_bone_name_restrictions:
-            check_bone_names(map(lambda x: x.name, bones))
-
         for bone in bones:
             psk_bone = Psk.Bone()
             try:
@@ -118,12 +185,30 @@ def build_psk(context, options: PskBuildOptions) -> PskBuildResult:
                 parent_tail = inverse_parent_rotation @ bone.parent.tail
                 location = (parent_tail - parent_head) + bone.head
             else:
-                armature_local_matrix = armature_object.matrix_local
+                def get_armature_local_matrix():
+                    match options.export_space:
+                        case 'WORLD':
+                            return armature_object.matrix_world
+                        case 'ARMATURE':
+                            return Matrix.Identity(4)
+                        case _:
+                            raise ValueError(f'Invalid export space: {options.export_space}')
+
+                armature_local_matrix = get_armature_local_matrix()
                 location = armature_local_matrix @ bone.head
                 bone_rotation = bone.matrix.to_quaternion().conjugated()
                 local_rotation = armature_local_matrix.to_3x3().to_quaternion().conjugated()
                 rotation = bone_rotation @ local_rotation
                 rotation.conjugate()
+                rotation = coordinate_system_default_rotation @ rotation
+
+            location = scale_matrix @ location
+
+            # If the armature object has been scaled, we need to scale the bone's location to match.
+            _, _, armature_object_scale = armature_object.matrix_world.decompose()
+            location.x *= armature_object_scale.x
+            location.y *= armature_object_scale.y
+            location.z *= armature_object_scale.z
 
             psk_bone.location.x = location.x
             psk_bone.location.y = location.y
@@ -148,66 +233,108 @@ def build_psk(context, options: PskBuildOptions) -> PskBuildResult:
                                                                             material.psk.mesh_triangle_bit_flags)
         psk.materials.append(psk_material)
 
+    # TODO: This wasn't left in a good state. We should detect if we need to add a "default" material.
+    #  This can be done by checking if there is an empty material slot on any of the mesh objects, or if there are
+    #  no material slots on any of the mesh objects.
+    #  If so, it should be added to the end of the list of materials, and its index should mapped to a None value in the
+    #  material indices list.
+    if len(psk.materials) == 0:
+        # Add a default material if no materials are present.
+        psk_material = Psk.Material()
+        psk_material.name = bytes('None', encoding='windows-1252')
+        psk.materials.append(psk_material)
+
     context.window_manager.progress_begin(0, len(input_objects.mesh_objects))
 
     material_names = [m.name for m in options.materials]
 
     for object_index, input_mesh_object in enumerate(input_objects.mesh_objects):
 
+        obj, instance_objects, matrix_world = input_mesh_object.obj, input_mesh_object.instance_objects, input_mesh_object.matrix_world
+
         should_flip_normals = False
 
+        def get_material_name_indices(obj: Object, material_names: List[str]) -> Iterable[int]:
+            '''
+            Returns the index of the material in the list of material names.
+            If the material is not found, the index 0 is returned.
+            '''
+            for material_slot in obj.material_slots:
+                if material_slot.material is None:
+                    yield 0
+                else:
+                    try:
+                        yield material_names.index(material_slot.material.name)
+                    except ValueError:
+                        yield 0
+
         # MATERIALS
-        material_indices = [material_names.index(material_slot.material.name) for material_slot in input_mesh_object.material_slots]
+        material_indices = list(get_material_name_indices(obj, material_names))
+
+        if len(material_indices) == 0:
+            # Add a default material if no materials are present.
+            material_indices = [0]
 
         # MESH DATA
-        if options.use_raw_mesh_data:
+        match options.object_eval_state:
-            mesh_object = input_mesh_object
+            case 'ORIGINAL':
-            mesh_data = input_mesh_object.data
+                mesh_object = obj
-        else:
+                mesh_data = obj.data
-            # Create a copy of the mesh object after non-armature modifiers are applied.
+            case 'EVALUATED':
+                # Create a copy of the mesh object after non-armature modifiers are applied.
 
-            # Temporarily force the armature into the rest position.
+                # Temporarily force the armature into the rest position.
-            # We will undo this later.
+                # We will undo this later.
-            old_pose_position = None
+                old_pose_position = None
-            if armature_object is not None:
+                if armature_object is not None:
-                old_pose_position = armature_object.data.pose_position
+                    old_pose_position = armature_object.data.pose_position
-                armature_object.data.pose_position = 'REST'
+                    armature_object.data.pose_position = 'REST'
 
-            depsgraph = context.evaluated_depsgraph_get()
+                depsgraph = context.evaluated_depsgraph_get()
-            bm = bmesh.new()
+                bm = bmesh.new()
-            bm.from_object(input_mesh_object, depsgraph)
-            mesh_data = bpy.data.meshes.new('')
-            bm.to_mesh(mesh_data)
-            del bm
-            mesh_object = bpy.data.objects.new('', mesh_data)
-            mesh_object.matrix_world = input_mesh_object.matrix_world
 
-            scale = (input_mesh_object.scale.x, input_mesh_object.scale.y, input_mesh_object.scale.z)
+                try:
+                    bm.from_object(obj, depsgraph)
+                except ValueError:
+                    raise RuntimeError(f'Object "{obj.name}" is not evaluated.\n'
+                    'This is likely because the object is in a collection that has been excluded from the view layer.')
 
-            # Negative scaling in Blender results in inverted normals after the scale is applied. However, if the scale
+                mesh_data = bpy.data.meshes.new('')
-            # is not applied, the normals will appear unaffected in the viewport. The evaluated mesh data used in the
+                bm.to_mesh(mesh_data)
-            # export will have the scale applied, but this behavior is not obvious to the user.
+                del bm
-            #
+                mesh_object = bpy.data.objects.new('', mesh_data)
-            # In order to have the exporter be as WYSIWYG as possible, we need to check for negative scaling and invert
+                mesh_object.matrix_world = matrix_world
-            # the normals if necessary. If two axes have negative scaling and the third has positive scaling, the
-            # normals will be correct. We can detect this by checking if the number of negative scaling axes is odd. If
-            # it is, we need to invert the normals of the mesh by swapping the order of the vertices in each face.
-            should_flip_normals = sum(1 for x in scale if x < 0) % 2 == 1
 
-            # Copy the vertex groups
+                # Extract the scale from the matrix.
-            for vertex_group in input_mesh_object.vertex_groups:
+                _, _, scale = matrix_world.decompose()
-                mesh_object.vertex_groups.new(name=vertex_group.name)
 
-            # Restore the previous pose position on the armature.
+                # Negative scaling in Blender results in inverted normals after the scale is applied. However, if the scale
-            if old_pose_position is not None:
+                # is not applied, the normals will appear unaffected in the viewport. The evaluated mesh data used in the
-                armature_object.data.pose_position = old_pose_position
+                # export will have the scale applied, but this behavior is not obvious to the user.
+                #
+                # In order to have the exporter be as WYSIWYG as possible, we need to check for negative scaling and invert
+                # the normals if necessary. If two axes have negative scaling and the third has positive scaling, the
+                # normals will be correct. We can detect this by checking if the number of negative scaling axes is odd. If
+                # it is, we need to invert the normals of the mesh by swapping the order of the vertices in each face.
+                should_flip_normals = sum(1 for x in scale if x < 0) % 2 == 1
+
+                # Copy the vertex groups
+                for vertex_group in obj.vertex_groups:
+                    mesh_object.vertex_groups.new(name=vertex_group.name)
+
+                # Restore the previous pose position on the armature.
+                if old_pose_position is not None:
+                    armature_object.data.pose_position = old_pose_position
+            case _:
+                raise ValueError(f'Invalid object evaluation state: {options.object_eval_state}')
 
         vertex_offset = len(psk.points)
+        matrix_world = scale_matrix @ export_space_matrix @ mesh_object.matrix_world
 
         # VERTICES
         for vertex in mesh_data.vertices:
             point = Vector3()
-            v = mesh_object.matrix_world @ vertex.co
+            v = matrix_world @ vertex.co
             point.x = v.x
             point.y = v.y
             point.z = v.z
@@ -287,6 +414,12 @@ def build_psk(context, options: PskBuildOptions) -> PskBuildResult:
                                 break
                             except ValueError:
                                 bone = bone.parent
+
+            # Keep track of which vertices have been assigned weights.
+            # The ones that have not been assigned weights will be assigned to the root bone.
+            # Without this, some older versions of UnrealEd may have corrupted meshes.
+            vertices_assigned_weights = np.full(len(mesh_data.vertices), False)
+
             for vertex_group_index, vertex_group in enumerate(mesh_object.vertex_groups):
                 if vertex_group_index not in vertex_group_bone_indices:
                     # Vertex group has no associated bone, skip it.
@@ -304,8 +437,18 @@ def build_psk(context, options: PskBuildOptions) -> PskBuildResult:
                     w.point_index = vertex_offset + vertex_index
                     w.weight = weight
                     psk.weights.append(w)
+                    vertices_assigned_weights[vertex_index] = True
 
-        if not options.use_raw_mesh_data:
+            # Assign vertices that have not been assigned weights to the root bone.
+            for vertex_index, assigned in enumerate(vertices_assigned_weights):
+                if not assigned:
+                    w = Psk.Weight()
+                    w.bone_index = 0
+                    w.point_index = vertex_offset + vertex_index
+                    w.weight = 1.0
+                    psk.weights.append(w)
+
+        if options.object_eval_state == 'EVALUATED':
             bpy.data.objects.remove(mesh_object)
             bpy.data.meshes.remove(mesh_data)
             del mesh_data

io_scene_psk_psa/psk/export/operators.py

@@ -1,41 +1,104 @@
+from typing import List, Optional, cast, Iterable
+
+import bpy
 from bpy.props import StringProperty
-from bpy.types import Operator
+from bpy.types import Operator, Context, Object, Collection, SpaceProperties, Depsgraph, Material
 from bpy_extras.io_utils import ExportHelper
 
-from ..builder import build_psk, PskBuildOptions, get_psk_input_objects
+from .properties import add_psk_export_properties
+from ..builder import build_psk, PskBuildOptions, get_psk_input_objects_for_context, \
+    get_psk_input_objects_for_collection
 from ..writer import write_psk
 from ...shared.helpers import populate_bone_collection_list
+from ...shared.ui import draw_bone_filter_mode
 
 
-def is_bone_filter_mode_item_available(context, identifier):
+def get_materials_for_mesh_objects(depsgraph: Depsgraph, mesh_objects: Iterable[Object]):
-    input_objects = get_psk_input_objects(context)
-    armature_object = input_objects.armature_object
-    if identifier == 'BONE_COLLECTIONS':
-        if armature_object is None or armature_object.data is None or len(armature_object.data.collections) == 0:
-            return False
-    # else if... you can set up other conditions if you add more options
-    return True
-
-
-def populate_material_list(mesh_objects, material_list):
-    material_list.clear()
-
     materials = []
     for mesh_object in mesh_objects:
-        for i, material_slot in enumerate(mesh_object.material_slots):
+        evaluated_mesh_object = mesh_object.evaluated_get(depsgraph)
+        for i, material_slot in enumerate(evaluated_mesh_object.material_slots):
             material = material_slot.material
-            # TODO: put this in the poll arg?
             if material is None:
                 raise RuntimeError('Material slot cannot be empty (index ' + str(i) + ')')
             if material not in materials:
                 materials.append(material)
+    return materials
 
+
+def populate_material_name_list(depsgraph: Depsgraph, mesh_objects, material_list):
+    materials = get_materials_for_mesh_objects(depsgraph, mesh_objects)
+    material_list.clear()
     for index, material in enumerate(materials):
         m = material_list.add()
-        m.material = material
+        m.material_name = material.name
         m.index = index
 
 
+
+def get_collection_from_context(context: Context) -> Optional[Collection]:
+    if context.space_data.type != 'PROPERTIES':
+        return None
+
+    space_data = cast(SpaceProperties, context.space_data)
+
+    if space_data.use_pin_id:
+        return cast(Collection, space_data.pin_id)
+    else:
+        return context.collection
+
+
+def get_collection_export_operator_from_context(context: Context) -> Optional[object]:
+    collection = get_collection_from_context(context)
+    if collection is None:
+        return None
+    if 0 > collection.active_exporter_index >= len(collection.exporters):
+        return None
+    exporter = collection.exporters[collection.active_exporter_index]
+    # TODO: make sure this is actually an ASE exporter.
+    return exporter.export_properties
+
+
+class PSK_OT_populate_bone_collection_list(Operator):
+    bl_idname = 'psk_export.populate_bone_collection_list'
+    bl_label = 'Populate Bone Collection List'
+    bl_description = 'Populate the bone collection list from the armature that will be used in this collection export'
+    bl_options = {'INTERNAL'}
+
+    def execute(self, context):
+        export_operator = get_collection_export_operator_from_context(context)
+        if export_operator is None:
+            self.report({'ERROR_INVALID_CONTEXT'}, 'No valid export operator found in context')
+            return {'CANCELLED'}
+        input_objects = get_psk_input_objects_for_collection(context.collection)
+        if input_objects.armature_object is None:
+            self.report({'ERROR_INVALID_CONTEXT'}, 'No armature found in collection')
+            return {'CANCELLED'}
+        populate_bone_collection_list(input_objects.armature_object, export_operator.bone_collection_list)
+        return {'FINISHED'}
+
+
+class PSK_OT_populate_material_name_list(Operator):
+    bl_idname = 'psk_export.populate_material_name_list'
+    bl_label = 'Populate Material Name List'
+    bl_description = 'Populate the material name list from the objects that will be used in this export'
+    bl_options = {'INTERNAL'}
+
+    def execute(self, context):
+        export_operator = get_collection_export_operator_from_context(context)
+        if export_operator is None:
+            self.report({'ERROR_INVALID_CONTEXT'}, 'No valid export operator found in context')
+            return {'CANCELLED'}
+        depsgraph = context.evaluated_depsgraph_get()
+        input_objects = get_psk_input_objects_for_collection(context.collection)
+        try:
+            populate_material_name_list(depsgraph, [x.obj for x in input_objects.mesh_objects], export_operator.material_name_list)
+        except RuntimeError as e:
+            self.report({'ERROR_INVALID_CONTEXT'}, str(e))
+            return {'CANCELLED'}
+        return {'FINISHED'}
+
+
 class PSK_OT_material_list_move_up(Operator):
     bl_idname = 'psk_export.material_list_item_move_up'
     bl_label = 'Move Up'
@@ -45,12 +108,12 @@ class PSK_OT_material_list_move_up(Operator):
     @classmethod
     def poll(cls, context):
         pg = getattr(context.scene, 'psk_export')
-        return pg.material_list_index > 0
+        return pg.material_name_list_index > 0
 
     def execute(self, context):
         pg = getattr(context.scene, 'psk_export')
-        pg.material_list.move(pg.material_list_index, pg.material_list_index - 1)
+        pg.material_name_list.move(pg.material_name_list_index, pg.material_name_list_index - 1)
-        pg.material_list_index -= 1
+        pg.material_name_list_index -= 1
         return {'FINISHED'}
 
 
@@ -63,110 +126,125 @@ class PSK_OT_material_list_move_down(Operator):
     @classmethod
     def poll(cls, context):
         pg = getattr(context.scene, 'psk_export')
-        return pg.material_list_index < len(pg.material_list) - 1
+        return pg.material_name_list_index < len(pg.material_name_list) - 1
 
     def execute(self, context):
         pg = getattr(context.scene, 'psk_export')
-        pg.material_list.move(pg.material_list_index, pg.material_list_index + 1)
+        pg.material_name_list.move(pg.material_name_list_index, pg.material_name_list_index + 1)
-        pg.material_list_index += 1
+        pg.material_name_list_index += 1
         return {'FINISHED'}
 
 
-class PSK_OT_export(Operator, ExportHelper):
+class PSK_OT_material_list_name_move_up(Operator):
-    bl_idname = 'export.psk'
+    bl_idname = 'psk_export.material_name_list_item_move_up'
+    bl_label = 'Move Up'
+    bl_options = {'INTERNAL'}
+    bl_description = 'Move the selected material name up one slot'
+
+    @classmethod
+    def poll(cls, context):
+        export_operator = get_collection_export_operator_from_context(context)
+        if export_operator is None:
+            return False
+        return export_operator.material_name_list_index > 0
+
+    def execute(self, context):
+        export_operator = get_collection_export_operator_from_context(context)
+        if export_operator is None:
+            self.report({'ERROR_INVALID_CONTEXT'}, 'No valid export operator found in context')
+            return {'CANCELLED'}
+        export_operator.material_name_list.move(export_operator.material_name_list_index, export_operator.material_name_list_index - 1)
+        export_operator.material_name_list_index -= 1
+        return {'FINISHED'}
+
+
+class PSK_OT_material_list_name_move_down(Operator):
+    bl_idname = 'psk_export.material_name_list_item_move_down'
+    bl_label = 'Move Down'
+    bl_options = {'INTERNAL'}
+    bl_description = 'Move the selected material name down one slot'
+
+    @classmethod
+    def poll(cls, context):
+        export_operator = get_collection_export_operator_from_context(context)
+        if export_operator is None:
+            return False
+        return export_operator.material_name_list_index < len(export_operator.material_name_list) - 1
+
+    def execute(self, context):
+        export_operator = get_collection_export_operator_from_context(context)
+        if export_operator is None:
+            self.report({'ERROR_INVALID_CONTEXT'}, 'No valid export operator found in context')
+            return {'CANCELLED'}
+        export_operator.material_name_list.move(export_operator.material_name_list_index, export_operator.material_name_list_index + 1)
+        export_operator.material_name_list_index += 1
+        return {'FINISHED'}
+
+
+empty_set = set()
+
+
+def get_sorted_materials_by_names(materials: Iterable[Material], material_names: List[str]) -> List[Material]:
+    """
+    Sorts the materials by the order of the material names list. Any materials not in the list will be appended to the
+    end of the list in the order they are found.
+    @param materials: A list of materials to sort
+    @param material_names: A list of material names to sort by
+    @return: A sorted list of materials
+    """
+    materials_in_collection = [m for m in materials if m.name in material_names]
+    materials_not_in_collection = [m for m in materials if m.name not in material_names]
+    materials_in_collection = sorted(materials_in_collection, key=lambda x: material_names.index(x.name))
+    return materials_in_collection + materials_not_in_collection
+
+
+def get_psk_build_options_from_property_group(mesh_objects: Iterable[Object],  pg: 'PSK_PG_export', depsgraph: Optional[Depsgraph] = None) -> PskBuildOptions:
+    if depsgraph is None:
+        depsgraph = bpy.context.evaluated_depsgraph_get()
+
+    options = PskBuildOptions()
+    options.object_eval_state = pg.object_eval_state
+    options.export_space = pg.export_space
+    options.bone_filter_mode = pg.bone_filter_mode
+    options.bone_collection_indices = [x.index for x in pg.bone_collection_list if x.is_selected]
+    options.scale = pg.scale
+    options.forward_axis = pg.forward_axis
+    options.up_axis = pg.up_axis
+
+    # TODO: perhaps move this into the build function and replace the materials list with a material names list.
+    materials = get_materials_for_mesh_objects(depsgraph, mesh_objects)
+    options.materials = get_sorted_materials_by_names(materials, [m.material_name for m in pg.material_name_list])
+
+    return options
+
+
+class PSK_OT_export_collection(Operator, ExportHelper):
+    bl_idname = 'export.psk_collection'
     bl_label = 'Export'
-    bl_options = {'INTERNAL', 'UNDO'}
+    bl_options = {'INTERNAL'}
-    __doc__ = 'Export mesh and armature to PSK'
     filename_ext = '.psk'
     filter_glob: StringProperty(default='*.psk', options={'HIDDEN'})
-
     filepath: StringProperty(
         name='File Path',
         description='File path used for exporting the PSK file',
         maxlen=1024,
-        default='')
+        default='',
-
+        subtype='FILE_PATH')
-    def invoke(self, context, event):
+    collection: StringProperty(options={'HIDDEN'})
-        try:
-            input_objects = get_psk_input_objects(context)
-        except RuntimeError as e:
-            self.report({'ERROR_INVALID_CONTEXT'}, str(e))
-            return {'CANCELLED'}
-
-        pg = getattr(context.scene, 'psk_export')
-
-        populate_bone_collection_list(input_objects.armature_object, pg.bone_collection_list)
-
-        try:
-            populate_material_list(input_objects.mesh_objects, pg.material_list)
-        except RuntimeError as e:
-            self.report({'ERROR_INVALID_CONTEXT'}, str(e))
-            return {'CANCELLED'}
-
-        context.window_manager.fileselect_add(self)
-
-        return {'RUNNING_MODAL'}
-
-    @classmethod
-    def poll(cls, context):
-        try:
-            get_psk_input_objects(context)
-        except RuntimeError as e:
-            cls.poll_message_set(str(e))
-            return False
-        return True
-
-    def draw(self, context):
-        layout = self.layout
-        pg = getattr(context.scene, 'psk_export')
-
-        # MESH
-        mesh_header, mesh_panel = layout.panel('01_mesh', default_closed=False)
-        mesh_header.label(text='Mesh', icon='MESH_DATA')
-        if mesh_panel:
-            mesh_panel.prop(pg, 'use_raw_mesh_data')
-
-        # BONES
-        bones_header, bones_panel = layout.panel('02_bones', default_closed=False)
-        bones_header.label(text='Bones', icon='BONE_DATA')
-        if bones_panel:
-            bone_filter_mode_items = pg.bl_rna.properties['bone_filter_mode'].enum_items_static
-            row = bones_panel.row(align=True)
-            for item in bone_filter_mode_items:
-                identifier = item.identifier
-                item_layout = row.row(align=True)
-                item_layout.prop_enum(pg, 'bone_filter_mode', item.identifier)
-                item_layout.enabled = is_bone_filter_mode_item_available(context, identifier)
-
-            if pg.bone_filter_mode == 'BONE_COLLECTIONS':
-                row = bones_panel.row()
-                rows = max(3, min(len(pg.bone_collection_list), 10))
-                row.template_list('PSX_UL_bone_collection_list', '', pg, 'bone_collection_list', pg, 'bone_collection_list_index', rows=rows)
-
-            bones_panel.prop(pg, 'should_enforce_bone_name_restrictions')
-
-        # MATERIALS
-        materials_header, materials_panel = layout.panel('03_materials', default_closed=False)
-        materials_header.label(text='Materials', icon='MATERIAL')
-        if materials_panel:
-            row = materials_panel.row()
-            rows = max(3, min(len(pg.bone_collection_list), 10))
-            row.template_list('PSK_UL_materials', '', pg, 'material_list', pg, 'material_list_index', rows=rows)
-            col = row.column(align=True)
-            col.operator(PSK_OT_material_list_move_up.bl_idname, text='', icon='TRIA_UP')
-            col.operator(PSK_OT_material_list_move_down.bl_idname, text='', icon='TRIA_DOWN')
 
     def execute(self, context):
-        pg = context.scene.psk_export
+        collection = bpy.data.collections.get(self.collection)
-        options = PskBuildOptions()
+
-        options.bone_filter_mode = pg.bone_filter_mode
-        options.bone_collection_indices = [x.index for x in pg.bone_collection_list if x.is_selected]
-        options.use_raw_mesh_data = pg.use_raw_mesh_data
-        options.materials = [m.material for m in pg.material_list]
-        options.should_enforce_bone_name_restrictions = pg.should_enforce_bone_name_restrictions
-        
         try:
-            result = build_psk(context, options)
+            input_objects = get_psk_input_objects_for_collection(collection, self.should_exclude_hidden_meshes)
+        except RuntimeError as e:
+            self.report({'ERROR_INVALID_CONTEXT'}, str(e))
+            return {'CANCELLED'}
+
+        options = get_psk_build_options_from_property_group([x.obj for x in input_objects.mesh_objects], self)
+
+        try:
+            result = build_psk(context, input_objects, options)
             for warning in result.warnings:
                 self.report({'WARNING'}, warning)
             write_psk(result.psk, self.filepath)
@@ -177,7 +255,161 @@ class PSK_OT_export(Operator, ExportHelper):
         except RuntimeError as e:
             self.report({'ERROR_INVALID_CONTEXT'}, str(e))
             return {'CANCELLED'}
-    
+
+        return {'FINISHED'}
+
+    def draw(self, context: Context):
+        layout = self.layout
+
+        flow = layout.grid_flow(row_major=True)
+        flow.use_property_split = True
+        flow.use_property_decorate = False
+
+        # MESH
+        mesh_header, mesh_panel = layout.panel('Mesh', default_closed=False)
+        mesh_header.label(text='Mesh', icon='MESH_DATA')
+        if mesh_panel:
+            flow = mesh_panel.grid_flow(row_major=True)
+            flow.use_property_split = True
+            flow.use_property_decorate = False
+            flow.prop(self, 'object_eval_state', text='Data')
+            flow.prop(self, 'should_exclude_hidden_meshes')
+
+        # BONES
+        bones_header, bones_panel = layout.panel('Bones', default_closed=False)
+        bones_header.label(text='Bones', icon='BONE_DATA')
+        if bones_panel:
+            draw_bone_filter_mode(bones_panel, self, True)
+            if self.bone_filter_mode == 'BONE_COLLECTIONS':
+                bones_panel.operator(PSK_OT_populate_bone_collection_list.bl_idname, icon='FILE_REFRESH')
+                rows = max(3, min(len(self.bone_collection_list), 10))
+                bones_panel.template_list('PSX_UL_bone_collection_list', '', self, 'bone_collection_list', self, 'bone_collection_list_index', rows=rows)
+
+        # MATERIALS
+        materials_header, materials_panel = layout.panel('Materials', default_closed=False)
+        materials_header.label(text='Materials', icon='MATERIAL')
+
+        if materials_panel:
+            materials_panel.operator(PSK_OT_populate_material_name_list.bl_idname, icon='FILE_REFRESH')
+            rows = max(3, min(len(self.material_name_list), 10))
+            row = materials_panel.row()
+            row.template_list('PSK_UL_material_names', '', self, 'material_name_list', self, 'material_name_list_index', rows=rows)
+            col = row.column(align=True)
+            col.operator(PSK_OT_material_list_name_move_up.bl_idname, text='', icon='TRIA_UP')
+            col.operator(PSK_OT_material_list_name_move_down.bl_idname, text='', icon='TRIA_DOWN')
+
+        # TRANSFORM
+        transform_header, transform_panel = layout.panel('Transform', default_closed=False)
+        transform_header.label(text='Transform')
+        if transform_panel:
+            flow = transform_panel.grid_flow(row_major=True)
+            flow.use_property_split = True
+            flow.use_property_decorate = False
+            flow.prop(self, 'export_space')
+            flow.prop(self, 'scale')
+            flow.prop(self, 'forward_axis')
+            flow.prop(self, 'up_axis')
+
+
+
+add_psk_export_properties(PSK_OT_export_collection)
+
+
+
+class PSK_OT_export(Operator, ExportHelper):
+    bl_idname = 'export.psk'
+    bl_label = 'Export'
+    bl_options = {'INTERNAL', 'UNDO'}
+    bl_description = 'Export mesh and armature to PSK'
+    filename_ext = '.psk'
+    filter_glob: StringProperty(default='*.psk', options={'HIDDEN'})
+    filepath: StringProperty(
+        name='File Path',
+        description='File path used for exporting the PSK file',
+        maxlen=1024,
+        default='')
+
+    def invoke(self, context, event):
+        try:
+            input_objects = get_psk_input_objects_for_context(context)
+        except RuntimeError as e:
+            self.report({'ERROR_INVALID_CONTEXT'}, str(e))
+            return {'CANCELLED'}
+
+        if len(input_objects.mesh_objects) == 0:
+            self.report({'ERROR_INVALID_CONTEXT'}, 'No mesh objects selected')
+            return {'CANCELLED'}
+
+        pg = getattr(context.scene, 'psk_export')
+
+        populate_bone_collection_list(input_objects.armature_object, pg.bone_collection_list)
+
+        depsgraph = context.evaluated_depsgraph_get()
+
+        try:
+            populate_material_name_list(depsgraph, [x.obj for x in input_objects.mesh_objects], pg.material_name_list)
+        except RuntimeError as e:
+            self.report({'ERROR_INVALID_CONTEXT'}, str(e))
+            return {'CANCELLED'}
+
+        context.window_manager.fileselect_add(self)
+
+        return {'RUNNING_MODAL'}
+
+    def draw(self, context):
+        layout = self.layout
+
+        pg = getattr(context.scene, 'psk_export')
+
+        # MESH
+        mesh_header, mesh_panel = layout.panel('Mesh', default_closed=False)
+        mesh_header.label(text='Mesh', icon='MESH_DATA')
+        if mesh_panel:
+            flow = mesh_panel.grid_flow(row_major=True)
+            flow.use_property_split = True
+            flow.use_property_decorate = False
+            flow.prop(pg, 'object_eval_state', text='Data')
+
+        # BONES
+        bones_header, bones_panel = layout.panel('Bones', default_closed=False)
+        bones_header.label(text='Bones', icon='BONE_DATA')
+        if bones_panel:
+            draw_bone_filter_mode(bones_panel, pg)
+            if pg.bone_filter_mode == 'BONE_COLLECTIONS':
+                row = bones_panel.row()
+                rows = max(3, min(len(pg.bone_collection_list), 10))
+                row.template_list('PSX_UL_bone_collection_list', '', pg, 'bone_collection_list', pg, 'bone_collection_list_index', rows=rows)
+
+        # MATERIALS
+        materials_header, materials_panel = layout.panel('Materials', default_closed=False)
+        materials_header.label(text='Materials', icon='MATERIAL')
+        if materials_panel:
+            row = materials_panel.row()
+            rows = max(3, min(len(pg.bone_collection_list), 10))
+            row.template_list('PSK_UL_material_names', '', pg, 'material_name_list', pg, 'material_name_list_index', rows=rows)
+            col = row.column(align=True)
+            col.operator(PSK_OT_material_list_move_up.bl_idname, text='', icon='TRIA_UP')
+            col.operator(PSK_OT_material_list_move_down.bl_idname, text='', icon='TRIA_DOWN')
+
+    def execute(self, context):
+        pg = getattr(context.scene, 'psk_export')
+
+        input_objects = get_psk_input_objects_for_context(context)
+        options = get_psk_build_options_from_property_group([x.obj for x in input_objects.mesh_objects], pg)
+
+        try:
+            result = build_psk(context, input_objects, options)
+            for warning in result.warnings:
+                self.report({'WARNING'}, warning)
+            write_psk(result.psk, self.filepath)
+            if len(result.warnings) > 0:
+                self.report({'WARNING'}, f'PSK export successful with {len(result.warnings)} warnings')
+            else:
+                self.report({'INFO'}, f'PSK export successful')
+        except RuntimeError as e:
+            self.report({'ERROR_INVALID_CONTEXT'}, str(e))
+            return {'CANCELLED'}
+
         return {'FINISHED'}
 
 
@@ -185,4 +417,9 @@ classes = (
     PSK_OT_material_list_move_up,
     PSK_OT_material_list_move_down,
     PSK_OT_export,
+    PSK_OT_export_collection,
+    PSK_OT_populate_bone_collection_list,
+    PSK_OT_populate_material_name_list,
+    PSK_OT_material_list_name_move_up,
+    PSK_OT_material_list_name_move_down,
 )

io_scene_psk_psa/psk/export/properties.py

@@ -1,40 +1,126 @@
-from bpy.props import EnumProperty, CollectionProperty, IntProperty, BoolProperty, PointerProperty
+from bpy.props import EnumProperty, CollectionProperty, IntProperty, PointerProperty, FloatProperty, StringProperty, \
+    BoolProperty
 from bpy.types import PropertyGroup, Material
 
+from ...shared.data import bone_filter_mode_items
 from ...shared.types import PSX_PG_bone_collection_list_item
 
 empty_set = set()
 
+object_eval_state_items = (
+    ('EVALUATED', 'Evaluated', 'Use data from fully evaluated object'),
+    ('ORIGINAL', 'Original', 'Use data from original object with no modifiers applied'),
+)
+
+export_space_items = [
+    ('WORLD', 'World', 'Export in world space'),
+    ('ARMATURE', 'Armature', 'Export in armature space'),
+]
+
+
+axis_identifiers = ('X', 'Y', 'Z', '-X', '-Y', '-Z')
+forward_items = (
+    ('X', 'X Forward', ''),
+    ('Y', 'Y Forward', ''),
+    ('Z', 'Z Forward', ''),
+    ('-X', '-X Forward', ''),
+    ('-Y', '-Y Forward', ''),
+    ('-Z', '-Z Forward', ''),
+)
+
+up_items = (
+    ('X', 'X Up', ''),
+    ('Y', 'Y Up', ''),
+    ('Z', 'Z Up', ''),
+    ('-X', '-X Up', ''),
+    ('-Y', '-Y Up', ''),
+    ('-Z', '-Z Up', ''),
+)
+
 class PSK_PG_material_list_item(PropertyGroup):
     material: PointerProperty(type=Material)
     index: IntProperty()
 
+class PSK_PG_material_name_list_item(PropertyGroup):
+    material_name: StringProperty()
+    index: IntProperty()
+
+
+
+
+def forward_axis_update(self, _context):
+    if self.forward_axis == self.up_axis:
+        # Automatically set the up axis to the next available axis
+        self.up_axis = next((axis for axis in axis_identifiers if axis != self.forward_axis), 'Z')
+
+
+def up_axis_update(self, _context):
+    if self.up_axis == self.forward_axis:
+        # Automatically set the forward axis to the next available axis
+        self.forward_axis = next((axis for axis in axis_identifiers if axis != self.up_axis), 'X')
+
+
+
+# In order to share the same properties between the PSA and PSK export properties, we need to define the properties in a
+# separate function and then apply them to the classes. This is because the collection exporter cannot have
+# PointerProperties, so we must effectively duplicate the storage of the properties.
+def add_psk_export_properties(cls):
+        cls.__annotations__['object_eval_state'] = EnumProperty(
+            items=object_eval_state_items,
+            name='Object Evaluation State',
+            default='EVALUATED'
+        )
+        cls.__annotations__['should_exclude_hidden_meshes'] = BoolProperty(
+            default=False,
+            name='Visible Only',
+            description='Export only visible meshes'
+        )
+        cls.__annotations__['scale'] = FloatProperty(
+            name='Scale',
+            default=1.0,
+            description='Scale factor to apply to the exported mesh and armature',
+            min=0.0001,
+            soft_max=100.0
+        )
+        cls.__annotations__['export_space'] = EnumProperty(
+            name='Export Space',
+            description='Space to export the mesh in',
+            items=export_space_items,
+            default='WORLD'
+        )
+        cls.__annotations__['bone_filter_mode'] = EnumProperty(
+            name='Bone Filter',
+            options=empty_set,
+            description='',
+            items=bone_filter_mode_items,
+        )
+        cls.__annotations__['bone_collection_list'] = CollectionProperty(type=PSX_PG_bone_collection_list_item)
+        cls.__annotations__['bone_collection_list_index'] = IntProperty(default=0)
+        cls.__annotations__['forward_axis'] = EnumProperty(
+            name='Forward',
+            items=forward_items,
+            default='X',
+            update=forward_axis_update
+        )
+        cls.__annotations__['up_axis'] = EnumProperty(
+            name='Up',
+            items=up_items,
+            default='Z',
+            update=up_axis_update
+        )
+        cls.__annotations__['material_name_list'] = CollectionProperty(type=PSK_PG_material_name_list_item)
+        cls.__annotations__['material_name_list_index'] = IntProperty(default=0)
+
 
 class PSK_PG_export(PropertyGroup):
-    bone_filter_mode: EnumProperty(
+    pass
-        name='Bone Filter',
+
-        options=empty_set,
+
-        description='',
+add_psk_export_properties(PSK_PG_export)
-        items=(
-            ('ALL', 'All', 'All bones will be exported'),
-            ('BONE_COLLECTIONS', 'Bone Collections',
-             'Only bones belonging to the selected bone collections and their ancestors will be exported')
-        )
-    )
-    bone_collection_list: CollectionProperty(type=PSX_PG_bone_collection_list_item)
-    bone_collection_list_index: IntProperty(default=0)
-    use_raw_mesh_data: BoolProperty(default=False, name='Raw Mesh Data', description='No modifiers will be evaluated as part of the exported mesh')
-    material_list: CollectionProperty(type=PSK_PG_material_list_item)
-    material_list_index: IntProperty(default=0)
-    should_enforce_bone_name_restrictions: BoolProperty(
-        default=False,
-        name='Enforce Bone Name Restrictions',
-        description='Enforce that bone names must only contain letters, numbers, spaces, hyphens and underscores.\n\n'
-                    'Depending on the engine, improper bone names might not be referenced correctly by scripts'
-    )
 
 
 classes = (
     PSK_PG_material_list_item,
+    PSK_PG_material_name_list_item,
     PSK_PG_export,
 )

io_scene_psk_psa/psk/export/ui.py

@@ -1,12 +1,14 @@
+import bpy
 from bpy.types import UIList
 
 
-class PSK_UL_materials(UIList):
+class PSK_UL_material_names(UIList):
     def draw_item(self, context, layout, data, item, icon, active_data, active_propname, index):
         row = layout.row()
-        row.prop(item.material, 'name', text='', emboss=False, icon_value=layout.icon(item.material))
+        material = bpy.data.materials.get(item.material_name, None)
+        row.prop(item, 'material_name', text='', emboss=False, icon_value=layout.icon(material) if material else 0)
 
 
 classes = (
-    PSK_UL_materials,
+    PSK_UL_material_names,
 )

io_scene_psk_psa/psk/import_/operators.py

@@ -13,8 +13,9 @@ empty_set = set()
 
 class PSK_FH_import(FileHandler):
     bl_idname = 'PSK_FH_import'
-    bl_label = 'File handler for Unreal PSK/PSKX import'
+    bl_label = 'Unreal PSK'
     bl_import_operator = 'import_scene.psk'
+    bl_export_operator = 'export.psk_collection'
     bl_file_extensions = '.psk;.pskx'
 
     @classmethod
@@ -26,7 +27,7 @@ class PSK_OT_import(Operator, ImportHelper):
     bl_idname = 'import_scene.psk'
     bl_label = 'Import'
     bl_options = {'INTERNAL', 'UNDO', 'PRESET'}
-    __doc__ = 'Load a PSK file'
+    bl_description = 'Import a PSK file'
     filename_ext = '.psk'
     filter_glob: StringProperty(default='*.psk;*.pskx', options={'HIDDEN'})
     filepath: StringProperty(
@@ -101,6 +102,12 @@ class PSK_OT_import(Operator, ImportHelper):
         default=1.0,
         soft_min=0.0,
     )
+    bdk_repository_id: StringProperty(
+        name='BDK Repository ID',
+        default='',
+        options=empty_set,
+        description='The ID of the BDK repository to use for loading materials'
+    )
 
     def execute(self, context):
         psk = read_psk(self.filepath)
@@ -118,6 +125,9 @@ class PSK_OT_import(Operator, ImportHelper):
         options.should_import_shape_keys = self.should_import_shape_keys
         options.scale = self.scale
 
+        if self.bdk_repository_id:
+            options.bdk_repository_id = self.bdk_repository_id
+
         if not options.should_import_mesh and not options.should_import_skeleton:
             self.report({'ERROR'}, 'Nothing to import')
             return {'CANCELLED'}
@@ -142,6 +152,7 @@ class PSK_OT_import(Operator, ImportHelper):
         col.use_property_split = True
         col.use_property_decorate = False
         col.prop(self, 'scale')
+        col.prop(self, 'export_space')
 
         mesh_header, mesh_panel = layout.panel('mesh_panel_id', default_closed=False)
         mesh_header.prop(self, 'should_import_mesh')

io_scene_psk_psa/psk/importer.py

@@ -25,6 +25,7 @@ class PskImportOptions:
         self.bone_length = 1.0
         self.should_import_materials = True
         self.scale = 1.0
+        self.bdk_repository_id = None
 
 
 class ImportBone:
@@ -130,7 +131,8 @@ def import_psk(psk: Psk, context, options: PskImportOptions) -> PskImportResult:
                     # Material does not yet exist, and we have the BDK addon installed.
                     # Attempt to load it using BDK addon's operator.
                     material_reference = psk.material_references[material_index]
-                    if material_reference and bpy.ops.bdk.link_material(reference=material_reference) == {'FINISHED'}:
+                    repository_id = options.bdk_repository_id if options.bdk_repository_id is not None else ''
+                    if material_reference and bpy.ops.bdk.link_material(reference=material_reference, repository_id=repository_id) == {'FINISHED'}:
                         material = bpy.data.materials[material_name]
                 else:
                     # Just create a blank material.

io_scene_psk_psa/psk/reader.py

@@ -36,41 +36,43 @@ def read_psk(path: str) -> Psk:
         while fp.read(1):
             fp.seek(-1, 1)
             section = Section.from_buffer_copy(fp.read(ctypes.sizeof(Section)))
-            if section.name == b'ACTRHEAD':
+            match section.name:
-                pass
+                case b'ACTRHEAD':
-            elif section.name == b'PNTS0000':
+                    pass
-                _read_types(fp, Vector3, section, psk.points)
+                case b'PNTS0000':
-            elif section.name == b'VTXW0000':
+                    _read_types(fp, Vector3, section, psk.points)
-                if section.data_size == ctypes.sizeof(Psk.Wedge16):
+                case b'VTXW0000':
-                    _read_types(fp, Psk.Wedge16, section, psk.wedges)
+                    if section.data_size == ctypes.sizeof(Psk.Wedge16):
-                elif section.data_size == ctypes.sizeof(Psk.Wedge32):
+                        _read_types(fp, Psk.Wedge16, section, psk.wedges)
-                    _read_types(fp, Psk.Wedge32, section, psk.wedges)
+                    elif section.data_size == ctypes.sizeof(Psk.Wedge32):
-                else:
+                        _read_types(fp, Psk.Wedge32, section, psk.wedges)
-                    raise RuntimeError('Unrecognized wedge format')
+                    else:
-            elif section.name == b'FACE0000':
+                        raise RuntimeError('Unrecognized wedge format')
-                _read_types(fp, Psk.Face, section, psk.faces)
+                case b'FACE0000':
-            elif section.name == b'MATT0000':
+                    _read_types(fp, Psk.Face, section, psk.faces)
-                _read_types(fp, Psk.Material, section, psk.materials)
+                case b'MATT0000':
-            elif section.name == b'REFSKELT':
+                    _read_types(fp, Psk.Material, section, psk.materials)
-                _read_types(fp, Psk.Bone, section, psk.bones)
+                case b'REFSKELT':
-            elif section.name == b'RAWWEIGHTS':
+                    _read_types(fp, Psk.Bone, section, psk.bones)
-                _read_types(fp, Psk.Weight, section, psk.weights)
+                case b'RAWWEIGHTS':
-            elif section.name == b'FACE3200':
+                    _read_types(fp, Psk.Weight, section, psk.weights)
-                _read_types(fp, Psk.Face32, section, psk.faces)
+                case b'FACE3200':
-            elif section.name == b'VERTEXCOLOR':
+                    _read_types(fp, Psk.Face32, section, psk.faces)
-                _read_types(fp, Color, section, psk.vertex_colors)
+                case b'VERTEXCOLOR':
-            elif section.name.startswith(b'EXTRAUVS'):
+                    _read_types(fp, Color, section, psk.vertex_colors)
-                _read_types(fp, Vector2, section, psk.extra_uvs)
+                case b'VTXNORMS':
-            elif section.name == b'VTXNORMS':
+                    _read_types(fp, Vector3, section, psk.vertex_normals)
-                _read_types(fp, Vector3, section, psk.vertex_normals)
+                case b'MRPHINFO':
-            elif section.name == b'MRPHINFO':
+                    _read_types(fp, Psk.MorphInfo, section, psk.morph_infos)
-                _read_types(fp, Psk.MorphInfo, section, psk.morph_infos)
+                case b'MRPHDATA':
-            elif section.name == b'MRPHDATA':
+                    _read_types(fp, Psk.MorphData, section, psk.morph_data)
-                _read_types(fp, Psk.MorphData, section, psk.morph_data)
+                case _:
-            else:
+                    if section.name.startswith(b'EXTRAUVS'):
-                # Section is not handled, skip it.
+                        _read_types(fp, Vector2, section, psk.extra_uvs)
-                fp.seek(section.data_size * section.data_count, os.SEEK_CUR)
+                    else:
-                warnings.warn(f'Unrecognized section "{section.name} at position {fp.tell():15}"')
+                        # Section is not handled, skip it.
+                        fp.seek(section.data_size * section.data_count, os.SEEK_CUR)
+                        warnings.warn(f'Unrecognized section "{section.name} at position {fp.tell():15}"')
 
     '''
     UEViewer exports a sidecar file (*.props.txt) with fully-qualified reference paths for each material

io_scene_psk_psa/psk/writer.py

@@ -1,3 +1,4 @@
+import os
 from ctypes import Structure, sizeof
 from typing import Type
 
@@ -34,6 +35,9 @@ def write_psk(psk: Psk, path: str):
     elif len(psk.bones) == 0:
         raise RuntimeError(f'At least one bone must be marked for export')
 
+    # Make the directory for the file if it doesn't exist.
+    os.makedirs(os.path.dirname(path), exist_ok=True)
+
     with open(path, 'wb') as fp:
         _write_section(fp, b'ACTRHEAD')
         _write_section(fp, b'PNTS0000', Vector3, psk.points)

io_scene_psk_psa/shared/data.py

@@ -93,3 +93,9 @@ class Section(Structure):
     def __init__(self, *args, **kw):
         super().__init__(*args, **kw)
         self.type_flags = 1999801
+
+
+bone_filter_mode_items = (
+    ('ALL', 'All', 'All bones will be exported'),
+    ('BONE_COLLECTIONS', 'Bone Collections', 'Only bones belonging to the selected bone collections and their ancestors will be exported')
+)

io_scene_psk_psa/shared/dfs.py

@@ -0,0 +1,155 @@
+'''
+Depth-first object iterator functions for Blender collections and view layers.
+
+These functions are used to iterate over objects in a collection or view layer in a depth-first manner, including
+instances. This is useful for exporters that need to traverse the object hierarchy in a predictable order.
+'''
+
+from typing import Optional, Set, Iterable, List
+
+from bpy.types import Collection, Object, ViewLayer, LayerCollection
+from mathutils import Matrix
+
+
+class DfsObject:
+    '''
+    Represents an object in a depth-first search.
+    '''
+    def __init__(self, obj: Object, instance_objects: List[Object], matrix_world: Matrix):
+        self.obj = obj
+        self.instance_objects = instance_objects
+        self.matrix_world = matrix_world
+
+    @property
+    def is_visible(self) -> bool:
+        '''
+        Check if the object is visible.
+        @return: True if the object is visible, False otherwise.
+        '''
+        if self.instance_objects:
+            return self.instance_objects[-1].visible_get()
+        return self.obj.visible_get()
+
+    @property
+    def is_selected(self) -> bool:
+        '''
+        Check if the object is selected.
+        @return: True if the object is selected, False otherwise.
+        '''
+        if self.instance_objects:
+            return self.instance_objects[-1].select_get()
+        return self.obj.select_get()
+
+
+
+def _dfs_object_children(obj: Object, collection: Collection) -> Iterable[Object]:
+    '''
+    Construct a list of objects in hierarchy order from `collection.objects`, only keeping those that are in the
+    collection.
+    @param obj: The object to start the search from.
+    @param collection:  The collection to search in.
+    @return: An iterable of objects in hierarchy order.
+    '''
+    yield obj
+    for child in obj.children:
+        if child.name in collection.objects:
+            yield from _dfs_object_children(child, collection)
+
+
+def dfs_objects_in_collection(collection: Collection) -> Iterable[Object]:
+    '''
+    Returns a depth-first iterator over all objects in a collection, only keeping those that are directly in the
+    collection.
+    @param collection: The collection to search in.
+    @return: An iterable of objects in hierarchy order.
+    '''
+    objects_hierarchy = []
+    for obj in collection.objects:
+        if obj.parent is None or obj.parent not in set(collection.objects):
+            objects_hierarchy.append(obj)
+    for obj in objects_hierarchy:
+        yield from _dfs_object_children(obj, collection)
+
+
+def dfs_collection_objects(collection: Collection, visible_only: bool = False) -> Iterable[DfsObject]:
+    '''
+    Depth-first search of objects in a collection, including recursing into instances.
+    @param collection: The collection to search in.
+    @return: An iterable of tuples containing the object, the instance objects, and the world matrix.
+    '''
+    yield from _dfs_collection_objects_recursive(collection)
+
+
+def _dfs_collection_objects_recursive(
+        collection: Collection,
+        instance_objects: Optional[List[Object]] = None,
+        matrix_world: Matrix = Matrix.Identity(4),
+        visited: Optional[Set[Object]]=None
+) -> Iterable[DfsObject]:
+    '''
+    Depth-first search of objects in a collection, including recursing into instances.
+    This is a recursive function.
+    @param collection: The collection to search in.
+    @param instance_objects: The running hierarchy of instance objects.
+    @param matrix_world: The world matrix of the current object.
+    @param visited: A set of visited object-instance pairs.
+    @return: An iterable of tuples containing the object, the instance objects, and the world matrix.
+    '''
+
+    # We want to also yield the top-level instance object so that callers can inspect the selection status etc.
+    if visited is None:
+        visited = set()
+
+    if instance_objects is None:
+        instance_objects = list()
+
+    # First, yield all objects in child collections.
+    for child in collection.children:
+        yield from _dfs_collection_objects_recursive(child, instance_objects, matrix_world.copy(), visited)
+
+    # Then, evaluate all objects in this collection.
+    for obj in dfs_objects_in_collection(collection):
+        visited_pair = (obj, instance_objects[-1] if instance_objects else None)
+        if visited_pair in visited:
+            continue
+        # If this an instance, we need to recurse into it.
+        if obj.instance_collection is not None:
+            # Calculate the instance transform.
+            instance_offset_matrix = Matrix.Translation(-obj.instance_collection.instance_offset)
+            # Recurse into the instance collection.
+            yield from _dfs_collection_objects_recursive(obj.instance_collection,
+                                                         instance_objects + [obj],
+                                                         matrix_world @ (obj.matrix_world @ instance_offset_matrix),
+                                                         visited)
+        else:
+            # Object is not an instance, yield it.
+            yield DfsObject(obj, instance_objects, matrix_world @ obj.matrix_world)
+            visited.add(visited_pair)
+
+
+def dfs_view_layer_objects(view_layer: ViewLayer) -> Iterable[DfsObject]:
+    '''
+    Depth-first iterator over all objects in a view layer, including recursing into instances.
+    @param view_layer: The view layer to inspect.
+    @return: An iterable of tuples containing the object, the instance objects, and the world matrix.
+    '''
+    visited = set()
+    def layer_collection_objects_recursive(layer_collection: LayerCollection):
+        for child in layer_collection.children:
+            yield from layer_collection_objects_recursive(child)
+        # Iterate only the top-level objects in this collection first.
+        yield from _dfs_collection_objects_recursive(layer_collection.collection, visited=visited)
+
+    yield from layer_collection_objects_recursive(view_layer.layer_collection)
+
+
+def _is_dfs_object_visible(obj: Object, instance_objects: List[Object]) -> bool:
+    '''
+    Check if a DFS object is visible.
+    @param obj: The object.
+    @param instance_objects: The instance objects.
+    @return: True if the object is visible, False otherwise.
+    '''
+    if instance_objects:
+        return instance_objects[-1].visible_get()
+    return obj.visible_get()

io_scene_psk_psa/shared/helpers.py

@@ -1,10 +1,9 @@
-import re
+from typing import List, Iterable, cast, Tuple
-import typing
-from typing import List, Iterable
 
-import addon_utils
+import bpy
-import bpy.types
+from bpy.props import CollectionProperty
-from bpy.types import NlaStrip, Object, AnimData
+from bpy.types import AnimData, Object
+from bpy.types import Armature
 
 
 def rgb_to_srgb(c: float):
@@ -14,10 +13,9 @@ def rgb_to_srgb(c: float):
         return 12.92 * c
 
 
-def get_nla_strips_in_frame_range(animation_data: AnimData, frame_min: float, frame_max: float) -> List[NlaStrip]:
+def get_nla_strips_in_frame_range(animation_data: AnimData, frame_min: float, frame_max: float):
     if animation_data is None:
-        return []
+        return
-    strips = []
     for nla_track in animation_data.nla_tracks:
         if nla_track.mute:
             continue
@@ -25,11 +23,10 @@ def get_nla_strips_in_frame_range(animation_data: AnimData, frame_min: float, fr
             if (strip.frame_start < frame_min and strip.frame_end > frame_max) or \
                     (frame_min <= strip.frame_start < frame_max) or \
                     (frame_min < strip.frame_end <= frame_max):
-                strips.append(strip)
+                yield strip
-    return strips
 
 
-def populate_bone_collection_list(armature_object: Object, bone_collection_list: bpy.props.CollectionProperty) -> None:
+def populate_bone_collection_list(armature_object: Object, bone_collection_list: CollectionProperty) -> None:
     """
     Updates the bone collections collection.
 
@@ -54,7 +51,7 @@ def populate_bone_collection_list(armature_object: Object, bone_collection_list:
 
     bone_collection_list.clear()
 
-    armature = armature_object.data
+    armature = cast(Armature, armature_object.data)
 
     if armature is None:
         return
@@ -66,7 +63,7 @@ def populate_bone_collection_list(armature_object: Object, bone_collection_list:
     item.count = sum(map(lambda bone: 1 if len(bone.collections) == 0 else 0, armature.bones))
     item.is_selected = unassigned_collection_is_selected
 
-    for bone_collection_index, bone_collection in enumerate(armature.collections):
+    for bone_collection_index, bone_collection in enumerate(armature.collections_all):
         item = bone_collection_list.add()
         item.name = bone_collection.name
         item.index = bone_collection_index
@@ -74,16 +71,7 @@ def populate_bone_collection_list(armature_object: Object, bone_collection_list:
         item.is_selected = bone_collection.name in selected_assigned_collection_names if has_selected_collections else True
 
 
-def check_bone_names(bone_names: Iterable[str]):
+def get_export_bone_names(armature_object: Object, bone_filter_mode: str, bone_collection_indices: Iterable[int]) -> List[str]:
-    pattern = re.compile(r'^[a-zA-Z\d_\- ]+$')
-    invalid_bone_names = [x for x in bone_names if pattern.match(x) is None]
-    if len(invalid_bone_names) > 0:
-        raise RuntimeError(f'The following bone names are invalid: {invalid_bone_names}.\n'
-                           f'Bone names must only contain letters, numbers, spaces, hyphens and underscores.\n'
-                           f'You can bypass this by disabling "Enforce Bone Name Restrictions" in the export settings.')
-
-
-def get_export_bone_names(armature_object: Object, bone_filter_mode: str, bone_collection_indices: List[int]) -> List[str]:
     """
     Returns a sorted list of bone indices that should be exported for the given bone filter mode and bone collections.
 
@@ -91,20 +79,20 @@ def get_export_bone_names(armature_object: Object, bone_filter_mode: str, bone_c
 
     :param armature_object: Blender object with type 'ARMATURE'
     :param bone_filter_mode: One of ['ALL', 'BONE_COLLECTIONS']
-    :param bone_collection_indices: List of bone collection indices to be exported.
+    :param bone_collection_indices: A list of bone collection indices to export.
     :return: A sorted list of bone indices that should be exported.
     """
     if armature_object is None or armature_object.type != 'ARMATURE':
         raise ValueError('An armature object must be supplied')
 
-    armature_data = typing.cast(bpy.types.Armature, armature_object.data)
+    armature_data = cast(Armature, armature_object.data)
     bones = armature_data.bones
     bone_names = [x.name for x in bones]
 
     # Get a list of the bone indices that we are explicitly including.
     bone_index_stack = []
     is_exporting_unassigned_bone_collections = -1 in bone_collection_indices
-    bone_collections = list(armature_data.collections)
+    bone_collections = list(armature_data.collections_all)
 
     for bone_index, bone in enumerate(bones):
         # Check if this bone is in any of the collections in the bone collection indices list.
@@ -164,5 +152,59 @@ def get_export_bone_names(armature_object: Object, bone_filter_mode: str, bone_c
     return bone_names
 
 
-def is_bdk_addon_loaded():
+def is_bdk_addon_loaded() -> bool:
-    return addon_utils.check('bdk_addon')[1]
+    return 'bdk' in dir(bpy.ops)
+
+
+class SemanticVersion(object):
+    def __init__(self, version: Tuple[int, int, int]):
+        self.major, self.minor, self.patch = version
+
+    def __iter__(self):
+        yield self.major
+        yield self.minor
+        yield self.patch
+
+    @staticmethod
+    def compare(lhs: 'SemanticVersion', rhs: 'SemanticVersion') -> int:
+        """
+        Compares two semantic versions.
+
+        Returns:
+            -1 if lhs < rhs
+             0 if lhs == rhs
+             1 if lhs > rhs
+        """
+        for l, r in zip(lhs, rhs):
+            if l < r:
+                return -1
+            if l > r:
+                return 1
+        return 0
+
+    def __str__(self):
+        return f'{self.major}.{self.minor}.{self.patch}'
+
+    def __repr__(self):
+        return str(self)
+
+    def __eq__(self, other):
+        return self.compare(self, other) == 0
+
+    def __ne__(self, other):
+        return not self == other
+
+    def __lt__(self, other):
+        return self.compare(self, other) == -1
+
+    def __le__(self, other):
+        return self.compare(self, other) <= 0
+
+    def __gt__(self, other):
+        return self.compare(self, other) == 1
+
+    def __ge__(self, other):
+        return self.compare(self, other) >= 0
+
+    def __hash__(self):
+        return hash((self.major, self.minor, self.patch))

io_scene_psk_psa/shared/ui.py

@@ -0,0 +1,18 @@
+from bpy.types import UILayout
+
+from .data import bone_filter_mode_items
+
+
+def is_bone_filter_mode_item_available(pg, identifier):
+    if identifier == 'BONE_COLLECTIONS' and len(pg.bone_collection_list) == 0:
+        return False
+    return True
+
+
+def draw_bone_filter_mode(layout: UILayout, pg, should_always_show_bone_collections=False):
+    row = layout.row(align=True)
+    for item_identifier, _, _ in bone_filter_mode_items:
+        identifier = item_identifier
+        item_layout = row.row(align=True)
+        item_layout.prop_enum(pg, 'bone_filter_mode', item_identifier)
+        item_layout.enabled = should_always_show_bone_collections or is_bone_filter_mode_item_available(pg, identifier)