说明：  Chapter 7 Rational B-spline (NURBS) Surfaces basis.c tbasis.c Calculates the B-spline basis functions. frbsurf.c tfrbsurf.c Calculates and test the fast B-spline surface algorithm. knot.c tknot.c Calculates an open knot vector. rbspsurf.c trbsurf.c Calculates a rational B-spline (NURBS) surface. rbsurf.h Header file for fast rational B-spline surface program sumrbas.c Calculates the Sum function for a rational B-spline surface. chap7all.zip ZIP file for all of Chapter 7. chap7all.tar.gz UNIX tar file for all of Chapter 7.