A novel desktop computer-aided design system for early form design developments

In this paper a mixed desktop system utilizing computer aided design (CAD) and rapid prototyping (RP) technologies to support form design at the early stages of the design process is described. This new system is an image-mapping-based application in which a simple initial CAD model is modelled in a commercial package (Alias StudioTools) and then automatically updated by a software which uses pictures of its sculpted rapid prototyping model (RPM) representation. The automatic updating process is carried out by comparing the images of the primary CAD model and the picture of the sculpted RPM. The latter is taken by a simple digital camera or web-cam using the same coordinate transformations as the CAD model. The use of white and black stripes in the RPM and skinning sections in the CAD model allows the detection of differences between the two representations and hence, the updating of the primary CAD model. The new CAD model is then transferred back into StudioTools for further developments. This new approach is quicker and simpler to use than alternative technologies, such as three-dimensional scanning.