Shape Interrogation for Computer Aided Design and Manufacturing

Shape interrogation is the process of extraction of information from a geometric model. Shape interrogation is a fundamental component of Computer Aided Design and Manufacturing (CAD/CAM) systems and was first used in such context by M. Sabin, one of the pioneers of CAD/CAM, in the late sixties. The term surface interrogation has been used by I. Braid and A. Geisow in the same context. An alternate term nearly equivalent to shape interrogation is geometry processing first used by R. E. Barnhill, another pioneer of this field. In this book we focus on shape interrogation of geometric models bounded by free-form surfaces. Free-form surfaces, also called sculptured surfaces, are widely used in scientific and engineering applications. For example, the hydrodynamic shape of propeller blades has an important role in marine applications, and the aerodynamic shape of turbine blades determines the performance of aircraft engines. Free-form surfaces arise also in the bodies of ships, automobiles and aircraft, which have both functionality and attractive shape requirements. Many electronic devices as well as consumer products are designed with aesthetic shapes, which involve free-form surfaces.