Transformation of File Format in IGES Based on B-Rep Solid Model to STL

A new algorithm of transforming IGES files to STL files is presented. By the algorithm, we construct entities defined in the file and build the topological connection of entities according to information recorded in entities, spread the three-dimensional surface to planar plane, and transform the border loops to the planar plane too, then prune every surface according to the loops inside, triangulate the surface with reserved points on it and the points on the loops under the consistency of STL format, and finally output the legal STL file. The key point of the algorithm is to ensure the triangles created on the joint of faces correctly. At last, an instance of transformation is introduced.