UG-Interface for CAD Geometries

Numerical simulation of real-world problems in computer aided engineering often requires the processing of complex CAD geometries. Powerful tools with fast algorithms must be supplied in order to cope with the huge amount of data. As the software package UG, combining parallelism and adaptivity with multigrid methods on unstructured grids, represents the ideal platform for solving large-scale problems, we describe the rather technical way of how CAD geometries might be preprocessed in order to incorporate their geometry and volume mesh into UG. The parametric geometry description is replaced by a surface triangulation that is very fine with respect to the volume mesh. Since we focus on solving discretised partial differential equations with geometric multigrid methods, we provide a volume mesh as coarse as possible. For the users of this method, a short manual, introducing the tools applied here, is appended. keywords: CAD geometries, UG, mesh generation, solid modelling