Virtual Clay Modeling Methods Design And Application

A new kind of computer aided modeling, Virtual Clay Modeling (VCM) System, is developed in Northwestern Polytechnical University. Designers use the interactive virtual clay modeling tools, keyboard, mouse and space mouse, to carry out the cutting, pasting and cutting-pasting operations conveniently. They can achieve a satisfied production shape in the virtual modeling environment provided by VCM System. One of the key techniques in VCM is modeling method research.This paper primarily studies the virtual modeling methods and their realization algorithms in virtual clay modeling. Based on the theory of virtual clay modeling, it describes the cutting, pasting and cutting-pasting operation.There are three steps to realize these methods. First, swept volume surface modeling should be built by the shape and position from a moving modeling tool. Second, it is to discrete the tool swept surface modeling into uniformly distributed compressed voxel model. Third, in order to implement the virtual clay modeling, Boolean operations are fulfilled between tool swept volume and virtual clay model. In order to make designer in situ observation the result of modification of virtual clay model, it introduces the optimized Marching-Cubes algorithm to extract the surface triangle mesh of virtual clay model and display the final modeling result.These modeling methods were applied to the Virtual Clay Modeling System of automobile with excellent effect.