A new kind of NURBS representation for periodic curves is introduced. The method for periodic curves is extended to derive a compact and symmetric representation of the sphere or the ellipsoid using a piecewise bi-quadratic NURBS surface with only eight distinct control vertices.
['Kaihuai Qin', 'Wenping Wang', 'Zesheng Tang']
Representing spheres and ellipsoids using periodic NURBS surfaces with fewer control vertices