The objective of this seminar on CAD Tools for Products was to bring leading experts in the field of CAD-technology together and discuss research results and experience on advanced tools and methods that have the potential as a foundation for future CAD Systems. Multiresolution models with different levels of detail is a based tool for handling very large and complex systems in CAD-ship design, for instance-.We focus on automatic simplification algorithms for the generation of a multiresolution

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... family s,...s, of solid models from a BRep of an initial polyhedral solid S. Output BRep solids sk must represent valid polyhedra such that dist(surf(S), surf(,rk)) <= ekwith increasing 8«"8k =S-E-2«. On the other hand, coarser representations must be geometrically simpler, 7sz <nfk_,'v'k,nfk being the number of faces of sk. We have investigated algorithms based on an intermediate octree representation. An algorithm has been developed for the class of orthogonal polyhedra; an example involving the multiresolution simplification of a building model is presented and discussed. A second algorithm for general polyhedra, based on face octrees, is also presented and discussed. An algorithm for approximate skinning through cross-sectionalNURBS curves is presented. The method eliminates the problem of dealing with huge amounts of control points obtained during the curve compatibility process. It also allows the designer to specify large numbers of cross-sections and approximately fit a smooth surface to these curves to any given tolerance. Depending on the tolerance used, up to 99% of the control points can be eliminated. An adaptive algorithm to compute the medial axis transform of 2D polygonal domains is presented. The algorithm is based on the refinement of a coarse medial axis transform by