Generation of a computer model using parametric surfaces and polygonal meshes

摘要

A method of producing a control data set capable of controlling a machine tool. Processing means generate a parametric surface indicative of the shape of an object and mesh indicative of a shape of a relief, the relief comprising height contours and the mesh having at least one edge. The processor performs one of the following: project the mesh onto the surface; wrap the mesh on to the surface; intersect the mesh with the surface, so as to preserve the height contours of the relief relative to one another. The processor determines a trim boundary of the surface, the trim boundary having at least one edge, by performing one of the following: projecting the mesh into the surface; wrapping the mesh onto the surface; or intersecting the mesh with the surface, using the processor such that at least one edge of the mesh and at least one edge of the trim boundary are contiguous. Also disclosed is producing a computer model using a memory where the memory stores a first parameter relating to a trim boundary of a parametric surface and a second parameter relating to an outer edge of a polygonal mesh, where the two parameters have approximately the same value.