Description
Nowadays, in computer aided geometric design curves and surfaces are described by means of the combination of control points and blending functions.
In the first part of the talk those properties of combining functions will be summarized, which are necessary to the curves and surfaces in order to be suitable for geometric design.
Then the system of cyclic functions, defined in the space of trigonometric polynomials, and the properties of closed curves and surfaces generated by them will be shown.