AUTOMATED TRANSLATION OF HIGH ORDER COMPLEX GEOMETRY FROM A CAD MODEL INTO A SURFACE BASED COMBINATORIAL GEOMETRY FORMAT

摘要

A computer implemented process translates the high order complex geometry embodied in CAD software to the surface based combinatorial geometry (SBCG) format. The translation process is comprised of a set of lower-level algorithms that operate on two data sets which are commonly available from commercial CAD software systems. The process writes a list of trimmed surfaces (step 36) which make up a given part. These data are typically available from one of the standard geometry representations such as IGES, STEP, or ACIS. The process also writes a list of nodal data (step 38) : an appropriately dense grouping of point coordinates, designated as either inside or outside the part. These data may be obtained by discretizing solid geometry both within and external to the part of interest using standard FE tools (e.g. ProMechanica). The process translates these two data sets into a list of analytic surfaces and a well-posed zoning statement (step 40) and then optimizes that statement (step 50).