Inverse Relations for Blossoms and Parametrisations of Rational Curves and Surfaces

Abstract

In this paper, we make use of an inverse formula that relates the blossom of a NURBS curve, surface or Bézier triangle with its parametrisation, with no explicit reference to the control points and weights of the parametrisation. We make use of this inverse formula to raise and lower the degree elevation and reduction.

Keywords

• B-splines
• blossom
• polarisation identities
• degree elevation
• degree reduction