Second Order Surface Analysis

			        Using

		 Hybrid Symbolic and Numeric Operators



		    Gershon Elber and Elaine Cohen



			       UUCS-92-017


		     Department of Cumputer Science
			   University of Utah
		     Salt Lake City, UT 84112, USA


			        Abstract

Results from analyzing the curvature of a surface can be used to
improve the implementation, efficiency, and effectiveness of
manufacturing and visualization of sculptured surfaces.

	In this paper, we develop a robust method using hybrid
symbolic and numeric operators to create trimmed surfaces each of
which is solely convex, concave, or saddle and partitions the original
surface. The same method is also used to identify regions whose
curvature lies within prespecified bounds.