Rational Interpolants with Tension Parameters

In this paper we present a NURBS version of the rational interpolating spline with tension introduced in (Gregory, J. A.: Shape preserving spline interpolation, Computer Aided Design 18 (1986), 53-57), and we extend our proposal to the rectangular topology case. In particular we present some rational interpolating techniques that enable us to reconstruct shape-preserving bivariate NURBS and allow us to interactively modify the resulting surface by a set of tension parameters.