ch as GeomView, OpenInventor, LEDA Window or OpenGL. Some of them are particularly well suited to the visualization of 3D objects. The library is about 100,000 lines of C++ and can linked with other libraries written in C++, C or Fortran. Examples of such libraries are GMP number types or LEDA. CGAL is a powerful tool for the development of industrial applications since it provides robust implementations of ubiquitous geometric structures Delaunay triangulations and Voronoi diagrams to name two of them. Special care has been taken to handle degenerate geometric congurations known to arise frequently in practical settings. It 1 available at http://www.cs.uu.nl/CGAL. Research partially supported by the Esprit program #28155 (GALIA). should be emphasized that robustness does not preclude ef- ciency since the predicates the geometric algorithms rely on state-of-the-art arithmetic tools. Didactical issues have also been paid a special atten