Graphics Gems III (IBM Version)

V.4

GROUPING NEARLY COPLANAR POLYGONS INTO COPLANAR SETS

David Salesin and Filippo Tampieri,     Cornell University, Ithaca, New York

Publisher Summary

The propagation of errors in geometric algorithms is a very tricky problem. Small arithmetic errors in the computations may lead not only to errors in the numerical results—such as the coordinates of vertices and edges—but also to inconsistencies in the combinatorial results—such as the vertex and edge adjacencies in the topological description of an object. Inconsistencies can be a more serious problem than numerical errors as they can lead to infinite loops or a program that bombs out on certain inputs. For example, most polyhedral modelers that accommodate coplanar faces correctly handle ...