A method for representing quadric surfaces using NURBS is presented. By means of the necessary and sufficient conditions for
NURBS curves to precisely represent circular arcs and other conics, quadric surfaces can be represented by NURBS surfaces
with fewer control vertices. The method can be used not only for NURBS surface representation of quadric surfaces, but also
for rounding polyhedrons. Many examples are given in the paper.
Keywords NURBS surface - quadric surface - circular arc - conic
This project is supported by the National Natural Sciences Foundation of China.
For the biography ofQin Kaihuai, please refer to p.89, Vol.12, No.1 of this Journal.