Constructive Solid Geometry with Sculptured Primitives Using Inner and Outer Sets

Abstract

A new method for incorporating sculptured surfaces into a Constructive Solid Geometry (CSG) environment is described. As a preliminary, an overview of a general scheme for computations on CSG represented solids is given. The system, known as Inner Set Outer Set (ISOS), involves inner and outer bounding polyhedral approximations to the primitive solids and is detailed in [Beac89]. A method for simultaneous creation of both sculptured primitives and approximating geometry, by sweeping B-spline curves, appears in [Saia88]. This paper is concerned with expanding and adapting these methods to shapes of a less constrained nature, bounded by B-spline surfaces. The task encompasses theoretical groundwork in finding inner-bounding polyhedra and a reformulation of the underlying method.