Apparatus and method for displaying a trimmed surface on a computer graphics display system.

摘要

The invention relates to apparatus for displaying, on a computer graphics system, a trimmed surface (F''') defined by a surface description and at least one trimming curve (7), which comprises means for storing a description of at least one trimming curve which defines the portion of the surface to be trimmed, means for tessellating the surface to be trimmed into a plurality of polygons, means for determining whether the trimming curve intersects any of the polygons, means for creating a mask (9) which corresponds to the intersected polygon less the portion to be trimmed, means for comparing the polygon with the mask, and means for displaying the portion of the polygon corresponding to the mask. <IMAGE>