ABSTRACT
The problem of constructing smooth curves or surfaces satisfying certain con straints arises in different areas in CAGD. Typical examples are (scattered data) interpolation and the construction of blending surfaces. In scattered data interpolation one has to construct a surface which does not oscillate too much and goes through a sampled set of points in the space. Finding a blending surface (i.e. a smooth transition surface between primary sur faces) amounts to the construction of a reasonable surface that satisfies certain boundary conditions determined by the primary surfaces.
