export_fbx_bin.py

    "bake_anim", "bake_anim_use_nla_strips", "bake_anim_use_all_actions", "bake_anim_step", "bake_anim_simplify_factor",
    "use_metadata", "media_settings", "use_custom_properties",
))


# This func can be called with just the filepath
def save_single(operator, scene, filepath="",
                global_matrix=Matrix(),
                axis_up="Z",
                axis_forward="Y",
                context_objects=None,
                object_types=None,
                use_mesh_modifiers=True,
                mesh_smooth_type='FACE',
                bake_anim=True,
                bake_anim_use_nla_strips=True,
                bake_anim_use_all_actions=True,
                bake_anim_step=1.0,
                bake_anim_simplify_factor=1.0,
                use_metadata=True,
                path_mode='AUTO',
                use_mesh_edges=True,
                use_tspace=True,
                embed_textures=False,
                use_custom_properties=False,
                bake_space_transform=False,
                **kwargs
                ):

    if object_types is None:
        object_types = {'EMPTY', 'CAMERA', 'LAMP', 'ARMATURE', 'MESH', 'OTHER'}

    if 'OTHER' in object_types:
        object_types |= BLENDER_OTHER_OBJECT_TYPES

    global_scale = global_matrix.median_scale
    global_matrix_inv = global_matrix.inverted()
    # For transforming mesh normals.
    global_matrix_inv_transposed = global_matrix_inv.transposed()

    # Only embed textures in COPY mode!
    if embed_textures and path_mode != 'COPY':
        embed_textures = False

    media_settings = FBXSettingsMedia(
        path_mode,
        os.path.dirname(bpy.data.filepath),  # base_src
        os.path.dirname(filepath),  # base_dst
        # Local dir where to put images (medias), using FBX conventions.
        os.path.splitext(os.path.basename(filepath))[0] + ".fbm",  # subdir
        embed_textures,
        set(),  # copy_set
    )

    settings = FBXSettings(
        operator.report, (axis_up, axis_forward), global_matrix, global_scale,
        bake_space_transform, global_matrix_inv, global_matrix_inv_transposed,
        context_objects, object_types, use_mesh_modifiers,
        mesh_smooth_type, use_mesh_edges, use_tspace, False,
        bake_anim, bake_anim_use_nla_strips, bake_anim_use_all_actions, bake_anim_step, bake_anim_simplify_factor,
        False, media_settings, use_custom_properties,
    )

    import bpy_extras.io_utils

    print('\nFBX export starting... %r' % filepath)
    start_time = time.process_time()

    # Generate some data about exported scene...
    scene_data = fbx_data_from_scene(scene, settings)

    root = elem_empty(None, b"")  # Root element has no id, as it is not saved per se!

    # Mostly FBXHeaderExtension and GlobalSettings.
    fbx_header_elements(root, scene_data)

    # Documents and References are pretty much void currently.
    fbx_documents_elements(root, scene_data)
    fbx_references_elements(root, scene_data)

    # Templates definitions.
    fbx_definitions_elements(root, scene_data)

    # Actual data.
    fbx_objects_elements(root, scene_data)

    # How data are inter-connected.
    fbx_connections_elements(root, scene_data)

    # Animation.
    fbx_takes_elements(root, scene_data)

    # Cleanup!
    fbx_scene_data_cleanup(scene_data)

    # And we are down, we can write the whole thing!
    encode_bin.write(filepath, root, FBX_VERSION)

    # copy all collected files, if we did not embed them.
    if not media_settings.embed_textures:
        bpy_extras.io_utils.path_reference_copy(media_settings.copy_set)

    print('export finished in %.4f sec.' % (time.process_time() - start_time))
    return {'FINISHED'}


# defaults for applications, currently only unity but could add others.
def defaults_unity3d():
    return {
        "global_matrix": Matrix.Rotation(-math.pi / 2.0, 4, 'X'),
        "use_selection": False,
        "object_types": {'ARMATURE', 'EMPTY', 'MESH'},
        "use_mesh_modifiers": True,
        #"use_armature_deform_only": True,
        "bake_anim": True,
        #"use_anim_optimize": False,
        #"use_anim_action_all": True,
        "batch_mode": 'OFF',
        # Should really be True, but it can cause problems if a model is already in a scene or prefab
        # with the old transforms.
        "bake_space_transform": False,
    }


def save(operator, context,
         filepath="",
         use_selection=False,
         batch_mode='OFF',
         use_batch_own_dir=False,
         **kwargs
         ):
    """
    This is a wrapper around save_single, which handles multi-scenes (or groups) cases, when batch-exporting a whole
    .blend file.
    """

    ret = None

    org_mode = None
    if context.active_object and context.active_object.mode != 'OBJECT' and bpy.ops.object.mode_set.poll():
        org_mode = context.active_object.mode
        bpy.ops.object.mode_set(mode='OBJECT')

    if batch_mode == 'OFF':
        kwargs_mod = kwargs.copy()
        if use_selection:
            kwargs_mod["context_objects"] = context.selected_objects
        else:
            kwargs_mod["context_objects"] = context.scene.objects

        ret = save_single(operator, context.scene, filepath, **kwargs_mod)
    else:
        fbxpath = filepath

        prefix = os.path.basename(fbxpath)
        if prefix:
            fbxpath = os.path.dirname(fbxpath)

        if batch_mode == 'GROUP':
            data_seq = bpy.data.groups
        else:
            data_seq = bpy.data.scenes

        # call this function within a loop with BATCH_ENABLE == False
        # no scene switching done at the moment.
        # orig_sce = context.scene

        new_fbxpath = fbxpath  # own dir option modifies, we need to keep an original
        for data in data_seq:  # scene or group
            newname = "_".join((prefix, bpy.path.clean_name(data.name)))

            if use_batch_own_dir:
                new_fbxpath = os.path.join(fbxpath, newname)
                # path may already exist
                # TODO - might exist but be a file. unlikely but should probably account for it.

                if not os.path.exists(new_fbxpath):
                    os.makedirs(new_fbxpath)

            filepath = os.path.join(new_fbxpath, newname + '.fbx')

            print('\nBatch exporting %s as...\n\t%r' % (data, filepath))

            if batch_mode == 'GROUP':  # group
                # group, so objects update properly, add a dummy scene.
                scene = bpy.data.scenes.new(name="FBX_Temp")
                scene.layers = [True] * 20
                # bpy.data.scenes.active = scene # XXX, cant switch
                for ob_base in data.objects:
                    scene.objects.link(ob_base)

                scene.update()
                # TODO - BUMMER! Armatures not in the group wont animate the mesh
            else:
                scene = data

            kwargs_batch = kwargs.copy()
            kwargs_batch["context_objects"] = data.objects

            save_single(operator, scene, filepath, **kwargs_batch)

            if batch_mode == 'GROUP':
                # remove temp group scene
                bpy.data.scenes.remove(scene)

        # no active scene changing!
        # bpy.data.scenes.active = orig_sce

        ret = {'FINISHED'}  # so the script wont run after we have batch exported.

    if context.active_object and org_mode and bpy.ops.object.mode_set.poll():
        bpy.ops.object.mode_set(mode=org_mode)

    return ret