Solid Modeling Methods

There are two basic methods used to create solid models. They are Constructive Solid Geometry (CSG) methods, and Boundary Representation (Brep) methods. CSG uses solid primitives (rectangular prisms, spheres, cylinders, cones, etc.) and boolean operations (unions, subtractions, intersections) to create the solid model. Brep methods start with one or more wireframe profiles, and create a solid model by extruding, sweeping, revolving or skinning these profiles. The boolean operations can also be used on the profiles themselves and the solids generated from these profiles. Solids can also be created by combining surfaces, which often have complex shapes, through a sewing operation. This can be used, for example, to create the body of an aerodynamic vehicle such as an airplane, with its carefully designed wing profiles. Further details on these two different methods can be found in Zeid [Zeid]. These two methods can often be combined in order to create the desired parts. Each of these methods has its limitations, and parts which are very difficult to create using just one or the other method can be created much more easily using a combination of both methods. Thus, most commercial solid modeling systems are hybrids using both CSG and Brep methods.

Last Modified: Wed Aug 28 14:41:29 EDT 1996