feat(importing): Add better FBX bone orientations operator and accessory bone deletion

- Add new `apply_better_fbx_orientations` operator as standalone UI action for applying bone orientations
- Add "Delete Accessory Bones" property and UI toggle in EXTRAS panel for optional bone cleanup
- Move bone orientation logic from `modify_armature` execute method to new dedicated operator
- Refactor accessory bone deletion into separate method callable from new operator
- Update panel UI to show better FBX bones operator with delete accessory bones toggle option
- Register new operator in `__init__.py` and export from modifyarmature module
- Update interface dictionaries (English, Japanese, Chinese) with new UI strings
- Enable better FBX orientations and accessory deletion only for Koikatsu armature (C) selection
- Add detailed logging for bone operation counts and status tracking

importing/modifyarmature.py

@@ -346,9 +346,6 @@ class modify_armature(bpy.types.Operator):
             self.categorize_bones()
             self.rename_bones_for_clarity()
             self.rename_mmd_bones()
-            
-            # 最后再次应用 better_fbx 骨骼方向，确保不被其他步骤覆盖
-            self.apply_better_fbx_bone_orientations()
 
             self.apply_bone_widgets()
             self.hide_widgets()
@@ -488,10 +485,6 @@ class modify_armature(bpy.types.Operator):
         bpy.ops.armature.select_all(action='INVERT')
         bpy.ops.armature.delete()
         
-        # 只在选择 Koikatsu armature (C) 时删除配饰骨骼
-        if bpy.context.scene.kkbp.armature_dropdown == 'C':
-            self.delete_accessory_bones()
-        
         c.print_timer('delete_non_height_bones')
     
     def delete_accessory_bones(self):
@@ -1208,35 +1201,7 @@ class modify_armature(bpy.types.Operator):
                 armature.pose.bones[pmx_rename_dict[bone]].mmd_bone.name_j = bone
         c.print_timer('rename_mmd_bones')
 
-    def apply_better_fbx_bone_orientations(self):
-        '''统一应用 better_fbx 骨骼方向，确保不被其他步骤覆盖 (仅在选择 Koikatsu armature 时)'''
-        # 只在选择 Koikatsu armature (C) 时应用 better_fbx 骨骼方向
-        if bpy.context.scene.kkbp.armature_dropdown != 'C':
-            c.print_timer('apply_better_fbx_bone_orientations (skipped)')
-            return
-        
-        armature = c.get_armature()
-        c.switch(armature, 'edit')
-        
-        applied_count = 0
-        skipped_count = 0
-        
-        print("[KKBP] 应用 better_fbx 骨骼方向...")
-        
-        # 遍历字典中的所有骨骼并应用方向
-        for bone_name, offset in better_fbx_bone_tails.items():
-            if bone_name in armature.data.edit_bones:
-                bone = armature.data.edit_bones[bone_name]
-                bone.tail = bone.head + Vector(offset)
-                applied_count += 1
-            else:
-                skipped_count += 1
-        
-        print(f"[KKBP] 骨骼方向应用完成: {applied_count} 个已应用, {skipped_count} 个跳过")
-        print(f"[KKBP] 骨架总骨骼数: {len(armature.data.edit_bones)}")
-        
-        c.switch(armature, 'object')
-        c.print_timer('apply_better_fbx_bone_orientations')
+
     
     def visually_connect_bones(self):
         '''make sure certain bones are visually connected'''
@@ -2365,3 +2330,91 @@ class modify_armature(bpy.types.Operator):
             bone = c.get_armature().data.edit_bones.new(new_bone_name)
         return bone
 
+
+
+class apply_better_fbx_orientations(bpy.types.Operator):
+    bl_idname = "kkbp.applybetterfbxorientations"
+    bl_label = "应用 Better FBX 骨骼方向"
+    bl_description = "将骨骼方向修改为更自然的方向（基于 better_fbx 数据）。这会让骨骼沿着肢体方向延伸，而不是都朝上"
+    bl_options = {'REGISTER', 'UNDO'}
+    
+    def execute(self, context):
+        try:
+            armature = c.get_armature()
+            if not armature:
+                self.report({'ERROR'}, "未找到骨架对象")
+                return {'CANCELLED'}
+            
+            c.switch(armature, 'edit')
+            
+            # 记录删除前的骨骼数量
+            bones_before = len(armature.data.edit_bones)
+            print(f"[KKBP] 操作前骨骼数量: {bones_before}")
+            
+            # 如果勾选了删除配饰骨骼选项，先删除配饰骨骼
+            delete_option = context.scene.kkbp.delete_accessory_bones
+            print(f"[KKBP] 删除配饰骨骼选项: {delete_option}")
+            
+            if delete_option:
+                print("[KKBP] 开始删除配饰骨骼...")
+                self.delete_accessory_bones(armature)
+                bones_after_delete = len(armature.data.edit_bones)
+                print(f"[KKBP] 删除后骨骼数量: {bones_after_delete}")
+            else:
+                print("[KKBP] 跳过删除配饰骨骼")
+            
+            applied_count = 0
+            skipped_count = 0
+            
+            print("[KKBP] 应用 better_fbx 骨骼方向...")
+            
+            # 遍历字典中的所有骨骼并应用方向
+            for bone_name, offset in better_fbx_bone_tails.items():
+                if bone_name in armature.data.edit_bones:
+                    bone = armature.data.edit_bones[bone_name]
+                    bone.tail = bone.head + Vector(offset)
+                    applied_count += 1
+                else:
+                    skipped_count += 1
+            
+            c.switch(armature, 'object')
+            
+            self.report({'INFO'}, f"骨骼方向应用完成: {applied_count} 个已应用, {skipped_count} 个跳过")
+            print(f"[KKBP] 骨骼方向应用完成: {applied_count} 个已应用, {skipped_count} 个跳过")
+            print(f"[KKBP] 骨架总骨骼数: {len(armature.data.edit_bones)}")
+            
+            return {'FINISHED'}
+        except Exception as error:
+            c.handle_error(self, error)
+            return {"CANCELLED"}
+    
+    def delete_accessory_bones(self, armature):
+        '''删除不在 better_fbx_bone_tails 字典中的骨骼，只保留核心人体骨骼（仅用于 C 模式）'''
+        # 定义必须保留的骨骼（即使不在 better_fbx_bone_tails 中）
+        must_keep_bones = [
+            'cf_hit_head',          # 头部碰撞
+            'p_cf_body_bone',       # 身体骨骼
+            'p_cf_head_bone',       # 头部骨骼
+            'a_n_back',             # 背部锚点
+            'a_n_headside',         # 头部侧面锚点
+            'cf_J_hitomi_tx_R',     # 右眼瞳控制
+            'cf_J_hitomi_tx_L',     # 左眼瞳控制
+        ]
+        
+        # 收集所有需要删除的骨骼（不在 better_fbx_bone_tails 中且不在必须保留列表中的）
+        bones_to_delete = []
+        for bone in armature.data.edit_bones:
+            bone_name = bone.name
+            # 如果骨骼不在 better_fbx_bone_tails 字典中，且不在必须保留列表中，标记为删除
+            if bone_name not in better_fbx_bone_tails and bone_name not in must_keep_bones:
+                bones_to_delete.append(bone_name)
+        
+        # 删除标记的骨骼
+        deleted_count = 0
+        for bone_name in bones_to_delete:
+            if bone_name in armature.data.edit_bones:
+                armature.data.edit_bones.remove(armature.data.edit_bones[bone_name])
+                deleted_count += 1
+        
+        print(f"[KKBP] 已删除 {deleted_count} 个配饰骨骼（包括 IK 控制骨骼）")
+        print(f"[KKBP] 保留了 {len(better_fbx_bone_tails)} 个核心骨骼 + {len(must_keep_bones)} 个必需骨骼")