CP3: Robust, output-sensitive display of convex polyhedra in scanline mode

Abstract

A new technique is developed for displaying disjoint convex polyhedra. The method has the following properties: It is output-sensitive, displays the objects in scanline mode, and it is naturally robust. There is no complex data structure uniting the different polyhedra, so dynamic insertions and deletions are simple. Its robustness is based on a novel method of comparing depths by representative "axes" of objects instead of surfaces. The method is based on two extensions of the "critical-points" method for polygon scan conversion: One extension allows the efficient display of planar graphs in scanline mode, and another extension is into the third dimension. Test runs indicate that it compares extremely favorably with other methods that operate in scanline mode, as well as with standard software and hardware techniques of medium-level workstations.