CAD/CAM integration via skeleton-based modeling

The authors present an efficient parallel thinning algorithm for extracting both the medial surface and the medial axis (skeleton) of a three-dimensional object constructed using a geometric solid modeler. First, the object is converted into its voxel model using a ray tracing and filling scheme. A new Euler table is derived to ensure the invariance of the Euler characteristic. An octree data structure of 3×3×3 lattice points is constructed to examine the local connectivity. By preserving the Euler characteristic and the connectivity, the algorithm drastically reduces noisy branches in the skeleton. Pre- and post-processors are used to remove additional noise spurs. A noise-free skeleton model is constructed. The model has useful applications in linking CAD and CAM such as in casting and forging defect analysis