The Contribution of Removing Reconstructable Triangles in the Lossless Compression of a Triangular Mesh CAD Model

This paper evaluates the efficiency of widely used software tools, including gzip, OpenCTM and Google Draco, for the lossless compression of triangular meshes representing the surfaces of 3D CAD models. The suitability of removing reconstructable triangles from triangular meshes using CoToS software is also investigated and discussed in more detail. Three common input file formats are considered: OBJ, PLY and STL, the latter being the most widely used in engineering applications. A software testing tool is introduced to ensure consistent and reproducible evaluation of the selected compression methods. The results are instructive: for OBJ and PLY files, OpenCTM achieved the best compression performance, whereas for STL files, the best results were obtained by applying CoToS before OpenCTM. This combined approach reduced the input file size by more than a factor of ten.