ABSTRACT
An ¿-polyhedron can be represented by simple polyhedra. The simple ¿- polyhedra can be represented by their oriented supporting set of dimension i and their (i — l)-polyhedra of the boundary, etc. The boundary polyhedron characterizes the ¿-polyhedron because its orientation indicates which side of the supporting set faces interior and exterior. Such polyhedra curves and vertices, which are not boundary curves and vertices could additionally be used. Taken into the data model too, then there is no reason to distinguish them from the boundary curves and boundary vertices separately.
