The topological reconstruction algorithm for STL data based on red-black tree

The STL file is a kind of file that describes the solid's surface with triangular meshes. It is widely used in a lot of fields, such as Reverse Engineering and so on. But in STL files, the triangular facets and the vertexes are listed in unorder, and there are large numbers of redundant vertexes, which make the file hard to use in following jobs. So it's necessary to rebuild the topological structure. In this paper, a topological reconstruction algorithm based on red-black tree is presented. The algorithm takes the triangular facet as unit. Filtering the redundant vertexes and searching neighbor information are merged into one process. It also can be extended very well. The algorithm has been tested with many examples. All results show that it's both efficient and stable.