toroidal面型,在一般的radius设置曲率半径,就代表在子午面形成cylinder;在后面的radius of rotation设置曲率半径,就代表在弧矢面上形成cylinder。请注意,如果想形成cylinder时,radius and radius of rotation must be clear either, otherwise,the surface will be a tooidal. If you want to simulate a system with two cylinder surface upright to each other,you canset a parameter in the first surface on the Radius item and set a other parameter in the second face on the Rotation of Radius item.