Convexity conditions for parametric tensor-product B-spline surfaces (Q1293223)

Convexity is a useful property for CAGD applications. Four sets of sufficient conditions which ensure local convexity of a parametric tensor product B-spline surface patch are obtained in the paper. Relative weakness of the sets of conditions is also analytically examined and graphically illustrated [cf. \textit{B. Jüttler} in Goodman, Tim (ed.) et al., The mathematics of surfaces. VII. Proceedings of the 7th conference, Dundee, Great Britain, September 1996. Winchester: Information Geometers, 189--208 (1997; Zbl 0965.65027)].