Efficient Adaptive Subdivision of Bezier Surfaces

Abstract

The support of free-form surfaces by modem solid modeling systems has necessitated the development of hardware and algorithms for the interactive display of surface patches. This paper describes an algorithm for the display of multiple surface patches at frame rates capable of providing smooth motion. The algorithm runs on the Silicon Graphics IRIS 4D GT workstation. Real-time motion is achieved by exploiting a microcodable pipeline of floating point processors and existing support for the display of Gouraud shaded Z-buffered polygons. The paper presents tradeoffs in the development of a high performance rendering algorithm. We discuss issues related to hardware support, surface representation, adaptive display, and the minimization of display artifacts such as faceting and cracking. More detailed discussion addresses the choice of Bezier surface patches and subdivision criteria.