Using Volume Morphing to Alter Panel Designs to Compensate Shape Distortion in Assembly

Abstract

As automotive panels are assembled in a vehicle, they are subjected to shape distorting forces, e.g., the pressure of door seals. A standard technique for preventing shape distortions is to alter the panels’ computer aided design (CAD) in such a way that the panels assume the desired design shape under the action of the distorting forces. Volume morphing, a technique pioneered by (1978, “General Distortion of an Ensemble of Biparametric Patches,” Comput.-Aided Des., 10(2), pp. 116–120) and by and (1986, “Free-Form Deformation of Solid Geometric Models,” International Conference on Computer Graphics and Interactive Techniques, Proceedings of the 13th Annual Conference on Computer Graphics , pp. 151–160), has been extended and implemented in a computer software package called FESHAPE , created at the General Motors Research and Development Center. FESHAPE automatically modifies CAD models according to a finite set of displacement vectors obtained, e.g., from finite-element analysis or scanning tryout parts. This article discusses how FESHAPE has been successfully applied to compensate door panel distortion caused by door seals.