Automatic curve fairing system using visual languages

Generally, in the field of industrial design, the measurement data of a clay model are faired, and a 3D model is made in CAD. However, it is a problem that this fairing work takes a long time and requires a great deal of labor. We propose an automatic curve fairing system for the application to reverse engineering technology. The system is constructed by the following five steps. (1) Key-line data are extracted from a clay model by a 3D digitizer. (2) The extracted key-line data are approximated by a spline with a genetic algorithm. (3) The spline curve (key-line) is divided into curves of monotone curvature. (4) The “characteristic” of the curve is analyzed for each monotone-curvature curve. (5) Each monotone-curvature curve is substituted by a visual language based on the result of the analysis mentioned above, and each key-line is reconstructed by the visual language. By using this system, we can easily obtain an aesthetic curve, as intended by a designer, in a short time