Water Tight Surface Geometry From IGES, CAD and STEP Files

Pointwise, Inc. proposes development of a CAD file repair product that will allow general CAD files to be imported, converted to a precise analysis-ready form, and subsequently exported in generic CAD formats. The product will be based on the Gridgen grid generation software, and will proceed following five steps. First, CAD files from a variety of commercial and public-domain formats are imported. Next, a B-Rep manager is used to remove the unneeded and over-detailed regions of the model, ultimately grouping the pertinent pieces into a watertight topological representation. This is followed by graphical interactive assessment of the geometric errors present in the B-Rep model. From here a suite of geometric tools are utilized to repair the identified B-Rep mismatches and also to replace problematic surface sets with simplified single surfaces. Upon completion the B-Rep model will be geometrically accurate to the user's specification, at which time the final model is exported in either the IGES or STEP formats for use in analysis software such as grid generation. Numerical errors present in legacy IGES and CAD data present a substantial roadblock to efficient engineering analysis of the geometries such files model. Accurate viscous flow analysis is particularly sensitive to geometry errors, making mesh generation on such geometries a painstaking and time-intensive process. The analysis community would benefit greatly from a product able to offer robust CAD repair, especially if it were integrated directly within a grid generation product, whose needs for precise geometrical models are most critical. Such a product would be directly applicable to nearly all analysis applications.