Rational Approximation of Offset Surfaces by Using Bivariate S-power Basis

The algorithm about rational approximation of offset surfaces is given in this paper. Bivariate symmetric power basis is used here to approximate the radical expression of the given offset surface. There are two steps, first, we express the unit normal vector of offset surface by bivariate symmetric power basis; then, we present bivariate polynomial approximating expression of the radical expression. The algorithm is simple and effective. Numerical examples show that good approximate effects can be achieved along with the raise of the degree of bivariate symmetric power basis.