Analysis of STL files

STL files produced by 3D modelling systems contain triangular facet representation of surfaces and have become standard data inputs of rapid prototyping and manufacturing systems. In rapid prototyping technology, physical objects are produced layer by layer, each layer a 2D cross-section of the 3D mesh in STL format. In current CAD systems, the surface tessellation frequently ends with errors in the data structure as gaps and holes leading to open loops in the cross-sections that cannot be manufactured as layers. s paper, we present a method to detect defects in the surface representation and to analyse the shape of the approximated surface by constructing a polyhedral data structure from the STL file.