UE4静态网格体LOD的复制脚本（python实现复制LOD）

      项目中经过houdini engine bake之后，StaticMesh的LOD没有同步过去，要是全部手动设置会很麻烦（一般都有6个不同的lod，要分别设置各自的屏幕尺寸和三角百分比，如图红框所示）。

        把bake前的静态网格叫做SM_1,bake 之后的静态网格叫做SM_2, 写了个脚本，把SM_1的LOD赋值给SM-2：

#复制sm_1的参数到sm_2
def copy_lods(static_mesh1,static_mesh2):
    print("[HDA Baker]treating asset: " + static_mesh1.get_name())
    print("[HDA Baker]existing LOD count: " + str(unreal.EditorStaticMeshLibrary.get_lod_count(static_mesh1)))
    options = unreal.EditorScriptingMeshReductionOptions()
    # 读屏幕尺寸(数组)
    lod_sizes = unreal.EditorStaticMeshLibrary.get_lod_screen_sizes(static_mesh1)
    options.reduction_settings = []
    for lod_num,lod_size in zip(range(unreal.EditorStaticMeshLibrary.get_lod_count(static_mesh1)),lod_sizes):
        # 读三角百分比
        sm1_MeshReductionSettings = unreal.EditorStaticMeshLibrary.get_lod_reduction_settings(static_mesh1,lod_num)
        lod_triangle = sm1_MeshReductionSettings.percent_triangles
        # 读SM_1
        print("[HDA Baker]sm1 lod tri per: " + str(lod_triangle) + ",sm1 lod size: " + str(lod_size) )
        # 赋值到SM_2
        options.reduction_settings.append(unreal.EditorScriptingMeshReductionSettings(lod_triangle, lod_size))
    options.auto_compute_lod_screen_size = False
    unreal.EditorStaticMeshLibrary.set_lods(static_mesh2, options)
    #保存SM_2
    unreal.EditorAssetLibrary.save_loaded_asset(static_mesh2)
    print("[HDA Baker]new LOD count: " + str(unreal.EditorStaticMeshLibrary.get_lod_count(static_mesh2)))

#  全部copy lod
def final_copy_lod():
    copy_sm1_paths = get_all_sm1()
    for copy_sm1_path in copy_sm1_paths:
        asset = unreal.find_object(None, copy_sm1_path)
        copy_sm2_path = copy_sm1_path.replace('SM_1.SM_1', 'SM_2.SM_2')
        print('[HDA Baker]SM_2 Path:' + copy_sm2_path)
        asset2 = unreal.find_object(None, copy_sm2_path)
        copy_lods(asset, asset2)