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TW 473
Hendrik Speleers, Paul Dierckx, and Stefan Vandewalle
Weight control for modelling with NURPS surfaces
Abstract
NURPS surfaces are the rational extension of Powell-Sabin splines in their
normalized B-spline representation.
In this paper we study the influence of modifying the weights of a NURPS
surface. We describe the relation between the weights associated with a
control triangle and the points on the NURPS surface by means of a double
volume ratio.
We also extend the concept of Farin points for rational Bézier curves
to NURPS surfaces, resulting in weight points and weight triangles.
They admit a local weight control in a geometrically intuitive way.
