Efficient wire frame display of parametric surface patches

Abstract

In this thesis, we experimentally compare the fixed and variable parameter interval approaches (adaptive and modified adaptive subdivision methods) for efficient wire frame display of bicubic Bezier surface patches. We define "viewing quality" as the tolerance measure of error between displayed line segments and control polygon net. We measure "efficiency" in terms of the time taken to compute the wire frame for the same number of line segments or identical viewing quality. The improvement in the efficiency of the modified adaptive subdivision method over adaptive subdivision is notably pronounced for those surface patches which are flat in one parameter direction, e.g., ruled surfaces. All algorithms are implemented in Turbo PASCAL on a Trigem/AT running under DOS 3.1.