diff --git a/bbp_ng/OP_EXPORT_bmfile.py b/bbp_ng/OP_EXPORT_bmfile.py
index e69de29..4536cf6 100644
--- a/bbp_ng/OP_EXPORT_bmfile.py
+++ b/bbp_ng/OP_EXPORT_bmfile.py
@@ -0,0 +1,26 @@
+import bpy
+from . import PROP_preferences, UTIL_functions, UTIL_file_browser, UTIL_blender_mesh
+
+class BBP_OT_export_bmfile(bpy.types.Operator, UTIL_file_browser.ExportBmxFile):
+    """Save a Ballance Map File (BM File Spec 1.4)"""
+    bl_idname = "bbp.export_bmfile"
+    bl_label = "Export BM (Ballance Map) File"
+    bl_options = {'PRESET'}
+
+    @classmethod
+    def poll(self, context):
+        return PROP_preferences.get_raw_preferences().has_valid_blc_tex_folder()
+    
+    def execute(self, context):
+        UTIL_functions.message_box((self.general_get_filename(), ), 'Export BM File Path', 'INFO')
+        self.report({'INFO'}, "BM File Exporting Finished.")
+        return {'FINISHED'}
+    
+    def draw(self, context):
+        layout = self.layout
+
+def register() -> None:
+    bpy.utils.register_class(BBP_OT_export_bmfile)
+
+def unregister() -> None:
+    bpy.utils.unregister_class(BBP_OT_export_bmfile)
diff --git a/bbp_ng/OP_EXPORT_virtools.py b/bbp_ng/OP_EXPORT_virtools.py
index e69de29..e1211c5 100644
--- a/bbp_ng/OP_EXPORT_virtools.py
+++ b/bbp_ng/OP_EXPORT_virtools.py
@@ -0,0 +1,26 @@
+import bpy
+from . import PROP_preferences, UTIL_functions, UTIL_file_browser, UTIL_blender_mesh
+
+class BBP_OT_export_virtools(bpy.types.Operator, UTIL_file_browser.ExportVirtoolsFile):
+    """Export Virtools File"""
+    bl_idname = "bbp.export_virtools"
+    bl_label = "Export Virtools File"
+    bl_options = {'PRESET'}
+
+    @classmethod
+    def poll(self, context):
+        return PROP_preferences.get_raw_preferences().has_valid_blc_tex_folder()
+    
+    def execute(self, context):
+        UTIL_functions.message_box((self.general_get_filename(), ), 'Export Virtools File Path', 'INFO')
+        self.report({'INFO'}, "Virtools File Exporting Finished.")
+        return {'FINISHED'}
+    
+    def draw(self, context):
+        layout = self.layout
+
+def register() -> None:
+    bpy.utils.register_class(BBP_OT_export_virtools)
+
+def unregister() -> None:
+    bpy.utils.unregister_class(BBP_OT_export_virtools)
diff --git a/bbp_ng/OP_IMPORT_bmfile.py b/bbp_ng/OP_IMPORT_bmfile.py
index e69de29..863f1f6 100644
--- a/bbp_ng/OP_IMPORT_bmfile.py
+++ b/bbp_ng/OP_IMPORT_bmfile.py
@@ -0,0 +1,26 @@
+import bpy
+from . import PROP_preferences, UTIL_functions, UTIL_file_browser, UTIL_blender_mesh
+
+class BBP_OT_import_bmfile(bpy.types.Operator, UTIL_file_browser.ImportBmxFile):
+    """Load a Ballance Map File (BM File Spec 1.4)"""
+    bl_idname = "bbp.import_bmfile"
+    bl_label = "Import BM (Ballance Map) File"
+    bl_options = {'PRESET', 'UNDO'}
+
+    @classmethod
+    def poll(self, context):
+        return PROP_preferences.get_raw_preferences().has_valid_blc_tex_folder()
+    
+    def execute(self, context):
+        UTIL_functions.message_box((self.general_get_filename(), ), 'Import BM File Path', 'INFO')
+        self.report({'INFO'}, "BM File Importing Finished.")
+        return {'FINISHED'}
+    
+    def draw(self, context):
+        layout = self.layout
+
+def register() -> None:
+    bpy.utils.register_class(BBP_OT_import_bmfile)
+
+def unregister() -> None:
+    bpy.utils.unregister_class(BBP_OT_import_bmfile)
diff --git a/bbp_ng/OP_IMPORT_virtools.py b/bbp_ng/OP_IMPORT_virtools.py
index e69de29..caa10f3 100644
--- a/bbp_ng/OP_IMPORT_virtools.py
+++ b/bbp_ng/OP_IMPORT_virtools.py
@@ -0,0 +1,26 @@
+import bpy
+from . import PROP_preferences, UTIL_functions, UTIL_file_browser, UTIL_blender_mesh
+
+class BBP_OT_import_virtools(bpy.types.Operator, UTIL_file_browser.ImportVirtoolsFile):
+    """Import Virtools File"""
+    bl_idname = "bbp.import_virtools"
+    bl_label = "Import Virtools File"
+    bl_options = {'PRESET', 'UNDO'}
+
+    @classmethod
+    def poll(self, context):
+        return PROP_preferences.get_raw_preferences().has_valid_blc_tex_folder()
+    
+    def execute(self, context):
+        UTIL_functions.message_box((self.general_get_filename(), ), 'Import Virtools File Path', 'INFO')
+        self.report({'INFO'}, "Virtools File Importing Finished.")
+        return {'FINISHED'}
+    
+    def draw(self, context):
+        layout = self.layout
+
+def register() -> None:
+    bpy.utils.register_class(BBP_OT_import_virtools)
+
+def unregister() -> None:
+    bpy.utils.unregister_class(BBP_OT_import_virtools)
diff --git a/bbp_ng/OP_UV_flatten_uv.py b/bbp_ng/OP_UV_flatten_uv.py
index ad263c3..388f66d 100644
--- a/bbp_ng/OP_UV_flatten_uv.py
+++ b/bbp_ng/OP_UV_flatten_uv.py
@@ -1,12 +1,12 @@
 import bpy, mathutils, bmesh
 
-class FlattenParamBySize():
+class _FlattenParamBySize():
     mScaleSize: float
 
     def __init__(self, scale_size: float) -> None:
         self.mScaleSize = scale_size
 
-class FlattenParamByRefPoint():
+class _FlattenParamByRefPoint():
     mReferencePoint: int
     mReferenceUV: float
 
@@ -14,21 +14,21 @@ class FlattenParamByRefPoint():
         self.mReferencePoint = ref_point
         self.mReferenceUV = ref_point_uv
 
-class FlattenParam():
+class _FlattenParam():
     mUseRefPoint: bool
-    mParamData: FlattenParamBySize | FlattenParamByRefPoint
+    mParamData: _FlattenParamBySize | _FlattenParamByRefPoint
 
-    def __init__(self, use_ref_point: bool, data: FlattenParamBySize | FlattenParamByRefPoint) -> None:
+    def __init__(self, use_ref_point: bool, data: _FlattenParamBySize | _FlattenParamByRefPoint) -> None:
         self.mUseRefPoint = use_ref_point
         self.mParamData = data
 
     @classmethod
     def CreateByScaleSize(cls, scale_num: float):
-        return cls(False, FlattenParamBySize(scale_num))
+        return cls(False, _FlattenParamBySize(scale_num))
 
     @classmethod
     def CreateByRefPoint(cls, ref_point: int, ref_point_uv: float):
-        return cls(True, FlattenParamByRefPoint(ref_point, ref_point_uv))
+        return cls(True, _FlattenParamByRefPoint(ref_point, ref_point_uv))
 
 class BBP_OT_flatten_uv(bpy.types.Operator):
     """Flatten selected face UV. Only works for convex face"""
@@ -97,12 +97,12 @@ class BBP_OT_flatten_uv(bpy.types.Operator):
     def execute(self, context):
         # construct scale data
         if self.scale_mode == 'NUM':
-            scale_data: FlattenParam = FlattenParam.CreateByScaleSize(self.scale_number)
+            scale_data: _FlattenParam = _FlattenParam.CreateByScaleSize(self.scale_number)
         else:
-            scale_data: FlattenParam = FlattenParam.CreateByRefPoint(self.reference_point, self.reference_uv)
+            scale_data: _FlattenParam = _FlattenParam.CreateByRefPoint(self.reference_point, self.reference_uv)
 
         # do flatten uv and report
-        no_processed_count = real_flatten_uv(bpy.context.active_object.data,
+        no_processed_count = _real_flatten_uv(bpy.context.active_object.data,
                                               self.reference_edge, scale_data)
         if no_processed_count != 0:
             print("[Flatten UV] {} faces are not be processed correctly because process failed."
@@ -127,8 +127,8 @@ class BBP_OT_flatten_uv(bpy.types.Operator):
             layout.prop(self, "reference_point")
             layout.prop(self, "reference_uv")
 
-def real_flatten_uv(mesh: bpy.types.Mesh, reference_edge: int,
-                     scale_data: FlattenParam) -> int:
+def _real_flatten_uv(mesh: bpy.types.Mesh, reference_edge: int,
+                     scale_data: _FlattenParam) -> int:
     no_processed_count: int = 0
 
     # if no uv, create it
@@ -271,3 +271,9 @@ def real_flatten_uv(mesh: bpy.types.Mesh, reference_edge: int,
     # sync the result to view port
     bmesh.update_edit_mesh(mesh)
     return no_processed_count
+
+def register() -> None:
+    bpy.utils.register_class(BBP_OT_flatten_uv)
+
+def unregister() -> None:
+    bpy.utils.unregister_class(BBP_OT_flatten_uv)
diff --git a/bbp_ng/UTIL_preferences.py b/bbp_ng/PROP_preferences.py
similarity index 100%
rename from bbp_ng/UTIL_preferences.py
rename to bbp_ng/PROP_preferences.py
diff --git a/bbp_ng/UTIL_ballance_texture.py b/bbp_ng/UTIL_ballance_texture.py
index 4cb1b90..b4a60f2 100644
--- a/bbp_ng/UTIL_ballance_texture.py
+++ b/bbp_ng/UTIL_ballance_texture.py
@@ -1,6 +1,6 @@
 import bpy, bpy_extras
 import os, typing
-from . import UTIL_preferences, UTIL_functions
+from . import PROP_preferences, UTIL_functions
 
 ## Ballance Texture Usage
 #  The aim of this module is to make sure every Ballance texture only have 1 instance in Blender as much as we can 
@@ -55,7 +55,7 @@ from . import UTIL_preferences, UTIL_functions
 
 #region Assist Functions
 
-def get_ballance_texture_folder() -> str:
+def _get_ballance_texture_folder() -> str:
     """!
     Get Ballance texture folder from preferences.
 
@@ -64,13 +64,13 @@ def get_ballance_texture_folder() -> str:
     @return The path to Ballance texture folder.
     """
 
-    pref: UTIL_preferences.RawPreferences = UTIL_preferences.get_raw_preferences()
+    pref: PROP_preferences.RawPreferences = PROP_preferences.get_raw_preferences()
     if not pref.has_valid_blc_tex_folder():
         raise UTIL_functions.BBPException("No valid Ballance texture folder in preferences.")
     
     return pref.mBallanceTextureFolder
 
-def is_path_equal(path1: str, path2: str) -> bool:
+def _is_path_equal(path1: str, path2: str) -> bool:
     """!
     Check whether 2 path are equal.
 
@@ -189,8 +189,8 @@ def get_ballance_texture_filename(texpath: str) -> str | None:
     if filename not in g_ballanceTextureSet: return None
 
     # if file name matched, check whether it located in ballance texture folder
-    probe: str = os.path.join(get_ballance_texture_folder(), filename)
-    if not is_path_equal(probe, texpath): return None
+    probe: str = os.path.join(_get_ballance_texture_folder(), filename)
+    if not _is_path_equal(probe, texpath): return None
 
     return filename
 
@@ -228,7 +228,7 @@ def get_texture_filepath(tex: bpy.types.Image) -> str:
 
     # resolve image path
     absfilepath: str = bpy_extras.io_utils.path_reference(
-        tex.filepath, bpy.data.filepath, get_ballance_texture_folder(),
+        tex.filepath, bpy.data.filepath, _get_ballance_texture_folder(),
         'ABSOLUTE', "", None, None
     )
 
@@ -273,7 +273,7 @@ def load_ballance_texture(texname: str) -> bpy.types.Image:
     
     # load image
     # check existing image in any case. because we need make sure ballance texture is unique.
-    filepath: str = os.path.join(get_ballance_texture_folder(), texname)
+    filepath: str = os.path.join(_get_ballance_texture_folder(), texname)
     return bpy.data.images.load(filepath, check_existing = True)
 
 def load_other_texture(texname: str) -> bpy.types.Image:
@@ -331,9 +331,3 @@ def save_other_texture(tex: bpy.types.Image, filepath: str) -> str:
     tex.save(filepath)
 
 #endregion
-
-def register() -> None:
-    pass # nothing to register
-
-def unregister() -> None:
-    pass
diff --git a/bbp_ng/UTIL_blender_mesh.py b/bbp_ng/UTIL_blender_mesh.py
index e58796e..e54ee69 100644
--- a/bbp_ng/UTIL_blender_mesh.py
+++ b/bbp_ng/UTIL_blender_mesh.py
@@ -33,31 +33,31 @@ class FaceData():
     def is_indices_legal(self) -> bool:
         return len(self.mIndices) >= 3
 
-def flat_vxvector3(it: typing.Iterator[UTIL_virtools_types.VxVector3]) -> typing.Iterator[float]:
+def _flat_vxvector3(it: typing.Iterator[UTIL_virtools_types.VxVector3]) -> typing.Iterator[float]:
     for entry in it:
         yield entry.x
         yield entry.y
         yield entry.z
 
-def flat_vxvector2(it: typing.Iterator[UTIL_virtools_types.VxVector2]) -> typing.Iterator[float]:
+def _flat_vxvector2(it: typing.Iterator[UTIL_virtools_types.VxVector2]) -> typing.Iterator[float]:
     for entry in it:
         yield entry.x
         yield entry.y
 
-def flat_face_nml_index(nml_idx: array.array, nml_array: array.array) -> typing.Iterator[float]:
+def _flat_face_nml_index(nml_idx: array.array, nml_array: array.array) -> typing.Iterator[float]:
     for idx in nml_idx:
         pos: int = idx * 3
         yield nml_array[pos]
         yield nml_array[pos + 1]
         yield nml_array[pos + 2]
 
-def flat_face_uv_index(uv_idx: array.array, uv_array: array.array) -> typing.Iterator[float]:
+def _flat_face_uv_index(uv_idx: array.array, uv_array: array.array) -> typing.Iterator[float]:
     for idx in uv_idx:
         pos: int = idx * 2
         yield uv_array[pos]
         yield uv_array[pos + 1]
 
-def nest_custom_split_normal(nml_idx: array.array, nml_array: array.array) -> typing.Iterator[UTIL_virtools_types.ConstVxVector3]:
+def _nest_custom_split_normal(nml_idx: array.array, nml_array: array.array) -> typing.Iterator[UTIL_virtools_types.ConstVxVector3]:
     for idx in nml_idx:
         pos: int = idx * 3
         yield (nml_array[pos], nml_array[pos + 1], nml_array[pos + 2])
@@ -161,11 +161,11 @@ class MeshWriter():
         
         # add vertex data
         prev_vertex_pos_count: int = len(self.__mVertexPos)
-        self.__mVertexPos.extend(flat_vxvector3(data.mVertexPosition))
+        self.__mVertexPos.extend(_flat_vxvector3(data.mVertexPosition))
         prev_vertex_nml_count: int = len(self.__mVertexNormal)
-        self.__mVertexNormal.extend(flat_vxvector3(data.mVertexNormal))
+        self.__mVertexNormal.extend(_flat_vxvector3(data.mVertexNormal))
         prev_vertex_uv_count: int = len(self.__mVertexUV)
-        self.__mVertexUV.extend(flat_vxvector2(data.mVertexUV))
+        self.__mVertexUV.extend(_flat_vxvector2(data.mVertexUV))
         
         # add material slot data and create mtl remap
         mtl_remap: list[int] = []
@@ -203,7 +203,6 @@ class MeshWriter():
         if self.is_valid():
             # write mesh
             self.__write_mesh()
-
             # reset mesh
             self.__mAssocMesh = None
 
@@ -236,11 +235,11 @@ class MeshWriter():
         self.__mAssocMesh.loops.foreach_set('vertex_index', self.__mFacePosIndices)
         # add face vertex nml by function
         self.__mAssocMesh.loops.foreach_set('normal',
-            list(flat_face_nml_index(self.__mFaceNmlIndices, self.__mVertexNormal))
+            list(_flat_face_nml_index(self.__mFaceNmlIndices, self.__mVertexNormal))
         )
         # add face vertex uv by function
         self.__mAssocMesh.uv_layers[0].uv.foreach_set('vector',
-            list(flat_face_uv_index(self.__mFaceUvIndices, self.__mVertexUV))
+            list(_flat_face_uv_index(self.__mFaceUvIndices, self.__mVertexUV))
         )   # NOTE: blender 3.5 changed. UV must be visited by .uv, not the .data
 
         # iterate face to set face data
@@ -271,7 +270,7 @@ class MeshWriter():
 
         # set custom split normal data
         self.__mAssocMesh.normals_split_custom_set(
-            tuple(nest_custom_split_normal(self.__mFaceNmlIndices, self.__mVertexNormal))
+            tuple(_nest_custom_split_normal(self.__mFaceNmlIndices, self.__mVertexNormal))
         )
         # enable auto smooth. it is IMPORTANT
         self.__mAssocMesh.use_auto_smooth = True
@@ -285,13 +284,5 @@ class MeshWriter():
         # clear mtl slot because clear_geometry will not do this.
         self.__mAssocMesh.materials.clear()
         
-
-
 class MeshUVModifier():
     pass
-
-def register() -> None:
-    pass # nothing to register
-
-def unregister() -> None:
-    pass
diff --git a/bbp_ng/UTIL_file_browser.py b/bbp_ng/UTIL_file_browser.py
index 881274f..9dbfeee 100644
--- a/bbp_ng/UTIL_file_browser.py
+++ b/bbp_ng/UTIL_file_browser.py
@@ -95,9 +95,4 @@ class ImportDirectory(bpy_extras.io_utils.ImportHelper):
     
     def general_get_directory(self) -> str:
         return self.directory
-    
-def register() -> None:
-    pass # nothing to register
-
-def unregister() -> None:
-    pass
+    
\ No newline at end of file
diff --git a/bbp_ng/UTIL_functions.py b/bbp_ng/UTIL_functions.py
index 5aa27e8..727f1c5 100644
--- a/bbp_ng/UTIL_functions.py
+++ b/bbp_ng/UTIL_functions.py
@@ -1,3 +1,4 @@
+import bpy
 import math, typing
 
 class BBPException(Exception):
@@ -53,3 +54,19 @@ def limit_iterator(it: typing.Iterator[_TLimitIterator], limit_count: int) -> ty
         # It is okey because it naturally stop the iteration of this generator.
         yield next(it)
         counter += 1
+
+def message_box(message: tuple[str], title: str, icon: str):
+    """
+    Show a message box in Blender. Non-block mode.
+
+    @param message[in] The text this message box displayed. Each item in this param will show as a single line.
+    @param title[in] Message box title text.
+    @param icon[in] The icon this message box displayed.
+    """
+    def draw(self, context: bpy.types.Context):
+        layout = self.layout
+        for item in message:
+            layout.label(text=item, translate=False)
+
+    bpy.context.window_manager.popup_menu(draw, title = title, icon = icon)
+
diff --git a/bbp_ng/UTIL_virtools_types.py b/bbp_ng/UTIL_virtools_types.py
index f88b1a3..8a3067b 100644
--- a/bbp_ng/UTIL_virtools_types.py
+++ b/bbp_ng/UTIL_virtools_types.py
@@ -76,17 +76,17 @@ class VxColor():
         self.a = _a
         self.regulate()
 
-    def to_tuple_rgba(self) -> tuple[float, float, float, float]:
+    def to_tuple_rgba(self) -> ConstVxColorRGBA:
         return (self.r, self.g, self.b, self.a)
     
-    def to_tuple_rgb(self) -> tuple[float, float, float]:
+    def to_tuple_rgb(self) -> ConstVxColorRGB:
         return (self.r, self.g, self.b)
 
-    def from_tuple_rgba(self, val: tuple[float, float, float, float]) -> None:
+    def from_tuple_rgba(self, val: ConstVxColorRGBA) -> None:
         (self.r, self.g, self.b, self.a) = val
         self.regulate()
 
-    def from_tuple_rgb(self, val: tuple[float, float, float]) -> None:
+    def from_tuple_rgb(self, val: ConstVxColorRGB) -> None:
         (self.r, self.g, self.b) = val
         self.a = 1.0
         self.regulate()
diff --git a/bbp_ng/__init__.py b/bbp_ng/__init__.py
index e841d60..2390672 100644
--- a/bbp_ng/__init__.py
+++ b/bbp_ng/__init__.py
@@ -23,8 +23,8 @@ if "bpy" in locals():
 
 #endregion
 
-from . import UTIL_preferences, UTIL_file_browser, UTIL_ballance_texture
-from . import PROP_virtools_material
+from . import PROP_preferences, PROP_virtools_material
+from . import OP_IMPORT_bmfile, OP_EXPORT_bmfile, OP_IMPORT_virtools, OP_EXPORT_virtools
 from . import OP_UV_flatten_uv
 
 #region Menu
@@ -45,8 +45,18 @@ class BBP_MT_View3DMenu(bpy.types.Menu):
 
 MenuDrawer_t = typing.Callable[[typing.Any, typing.Any], None]
 
+def menu_drawer_import(self, context):
+    layout: bpy.types.UILayout = self.layout
+    layout.operator(OP_IMPORT_bmfile.BBP_OT_import_bmfile.bl_idname, text = "Ballance Map (.bmx)")
+    layout.operator(OP_IMPORT_virtools.BBP_OT_import_virtools.bl_idname, text = "Virtools File (.nmo/.cmo/.vmo) (experimental)")
+
+def menu_drawer_export(self, context):
+    layout: bpy.types.UILayout = self.layout
+    layout.operator(OP_EXPORT_bmfile.BBP_OT_export_bmfile.bl_idname, text = "Ballance Map (.bmx)")
+    layout.operator(OP_EXPORT_virtools.BBP_OT_export_virtools.bl_idname, text = "Virtools File (.nmo/.cmo/.vmo) (experimental)")
+
 def menu_drawer_view3d(self, context):
-    layout = self.layout
+    layout: bpy.types.UILayout = self.layout
     layout.menu(BBP_MT_View3DMenu.bl_idname)
 
 #endregion
@@ -54,7 +64,6 @@ def menu_drawer_view3d(self, context):
 #region Register and Unregister.
 
 g_BldClasses: tuple[typing.Any, ...] = (
-    OP_UV_flatten_uv.BBP_OT_flatten_uv,
     BBP_MT_View3DMenu,
 )
 
@@ -69,15 +78,22 @@ class MenuEntry():
 
 g_BldMenus: tuple[MenuEntry, ...] = (
      MenuEntry(bpy.types.VIEW3D_MT_editor_menus, False, menu_drawer_view3d),
+     MenuEntry(bpy.types.TOPBAR_MT_file_import, True, menu_drawer_import),
+     MenuEntry(bpy.types.TOPBAR_MT_file_export, True, menu_drawer_export),
 )
 
 def register() -> None:
     # register module
-    UTIL_preferences.register()
-    UTIL_file_browser.register()
-    UTIL_ballance_texture.register()
+    PROP_preferences.register()
     PROP_virtools_material.register()
 
+    OP_IMPORT_bmfile.register()
+    OP_EXPORT_bmfile.register()
+    OP_IMPORT_virtools.register()
+    OP_EXPORT_virtools.register()
+
+    OP_UV_flatten_uv.register()
+
     # register other classes
     for cls in g_BldClasses:
         bpy.utils.register_class(cls)
@@ -99,10 +115,15 @@ def unregister() -> None:
         bpy.utils.unregister_class(cls)
 
     # unregister modules
+    OP_UV_flatten_uv.unregister()
+
+    OP_EXPORT_virtools.unregister()
+    OP_IMPORT_virtools.unregister()
+    OP_EXPORT_bmfile.unregister()
+    OP_IMPORT_bmfile.unregister()
+
     PROP_virtools_material.unregister()
-    UTIL_ballance_texture.unregister()
-    UTIL_file_browser.unregister()
-    UTIL_preferences.unregister()
+    PROP_preferences.unregister()
 
 if __name__ == "__main__":
     register()