A Low Cost Antialiased Space Filled Voxelization Of Polygonal Objects

In a virtual sculpting environment, we manipulate objects as a set of volume elements (voxels). In order to start the sculpture process from a polygonal object, we have to discretize this object as a set of voxels. This step is called voxelization. Several voxelization methods have already been proposed, but none matches all of our criteria. In this paper, we propose a practical approach that handles these criteria, based on an optimized ray casting. The method provides a voxelization of the inner space of a polygonal object, and not only of its surface. It is designed to work with closed objects which may contain holes or tunnels. Even if our goal is not real time conversion, it is fast enough to provide voxelization of objects made of several thousands of triangles within few seconds. As voxelization is a 3D sampling process, it entails aliasing problems. Our method allows a reduction of aliasing by using a low cost oversampling in order to compute grey scale values for the voxels. Moreover our method has a very low cost in memory and allows unlimited voxelization size (but by disk size), even for low memory computers. Furthermore, the method can be used on a personal computer without specific graphics hardware.