中文说明：
off文件读取绘图函数，能读取顶点坐标和拓扑关系，并以此绘制三维模型图像，使用可以直接调用，需要注意参数的类型，只能读要取off。
English Description：
Off file read drawing function, can read vertex coordinates and topological relations, and draw 3D model image, use can be called directly, need to pay attention to the type of parameters, can only read to take off