A road map to solid modeling

摘要

The objective of solid modeling is to represent, manipulate andnreason about the 3D shape of solid physical objects by computer. Suchnrepresentations should be unambiguous. Solid modeling's majornapplication areas include design, manufacturing, computer vision,ngraphics and virtual reality. The field draws on diverse sources,nincluding numerical analysis, symbolic algebraic computation,napproximation theory, applied mathematics, point set topology, algebraicngeometry, computational geometry and databases. In this article, wenbegin with some mathematical foundations of the field. We next reviewnthe major representation schemata of solids. Then, major layers ofnabstraction in a typical solid modeling system are characterized. Thenlowest level of abstraction comprises a substratum of basic servicenalgorithms. At an intermediate level of abstraction there are algorithmsnfor larger, more conceptual operations. Finally, a yet higher level ofnabstraction presents to the user a functional view that is typicallyntargeted towards solid design. We look at some applications and at userninteraction concepts. The classical design paradigms of solid modelingnconcentrated on obtaining one specific final shape. Those paradigms arenbecoming supplanted by feature-based, constraint-based design paradigmsnthat are oriented more toward the design process and define classes ofnshape instances. These new paradigms venture into territory that has yetnto be explored systematically. Concurrent with this paradigm shift,nthere is also a shift in the system architecture towards modularizednconfederations of plug-compatible functional components