Circular Aperture/Obscuration: A Circular Aperture defines an annular region which vignettes all rays which strike the surface inside of the minimum radius, and outside of the maximum radius. If the ray is between the minimum and maximum radii, then the ray will be allowed to proceed. The Circular Obscuration is the complement of the Circular Aperture. _)yn6M'Dt
上次回答不够准确,上面是说明书上的定义。