@PaQ

Hi PaQ,

maybe someone can compare Marco's test model with this solution,
to see if there is a difference:

http://www.resurf3d.com/Objmesh2solid.htm

(The algorithm used in this software is based on the paper named Constructing C1 Surfaces of Arbitrary Topology using Biquadratic and Cicubic Splines written by Professor Jorg Peter.)

Regards
Stefan