On circularly-hidden surface removal

Abstract

Two points p and q are circularly-visible from each other, if there exists a circular are connecting p and q that does not intersect any obstacles. Circularly-hidden surface removal is to identify the circularly-visible portion of an environment, using the circular rays that are generated by rotating the points on a given half-plane about its bounding line. We first characterize the circularly-projected images of polygonal faces. Then, we show that circularly-hidden surface removal for polyhedral objects can be accomplished in O(n(2)alpha(n)) time, where n is the total number of edges of given polyhedrons. (C) 1998 Published by Elsevier Science B.V. All rights reserved.