1 Department of Mathematics, Technical University of Denmark2 Department of Applied Mathematics and Computer Science, Technical University of Denmark3 Vienna University of Technology
Given a surface in 3-space or scattered points from a surface, we investigate the problem of deciding whether the data may be fitted well by a cylindrical surface, a surface of revolution or a helical surface. Furthermore, we show how to compute an approximating surface and put special emphasis to basic shapes used in computer aided design. The algorithms apply methods of line geometry to the set of surface normals in combination with techniques of numerical approximation. The presented results possess applications in reverse engineering and computer aided manufacturing.