Simplification of triangle meshes for fast surface rendering of tomographic data

The generation of a surface model of tomographic medical data typically produces tens to hundreds of thousands of triangles. Real time manipulation of these models on medical workstations is often not possible because of the massive number of patches which must be rendered. It is therefore important to reduce the number of triangles in these models. The author presents an algorithm for the simplification (decimation) of triangle meshes used in surface rendering of tomographic data. The decimation is performed in two steps. The first step identifies and removes nearly degenerate triangles by merging vertices which are closer than a specified distance. The second step (which can be iterated) removes vertices which are close to the average plane formed by their associated triangles. The algorithm merges triangles in large relatively flat areas while preserving detail on other parts of the surface. Reductions in model size depend on the choice of the distance parameter, δ. The smaller the value of δ, the more accurate the reduced model; but the less the reduction in model size. Selection of an appropriate δ has been found to preserve the fidelity of the model while yielding reductions in model size of 45 to 88 percent