As-exact-as-possible repair of unprintable STL files

The class of models that can be represented by STL files is larger than the class of models that can be printed using additive manufacturing technologies. In this paper such a gap is formalized while providing an unambiguous description of all the mathematical entities involved in the modeling-printing pipeline. Possible defects of an STL file are formally defined and classified, and a fully automatic procedure is described to turn any such file into a printable model. The procedure is as exact as possible, meaning that no visible distortion is introduced unless it is strictly imposed by limitations of the printing device. Thanks to such an unprecedented flexibility and accuracy, this algorithm is expected to significantly simplify the modeling-printing process, in particular within the continuously emerging non-professional ”maker” communities. CR Categories: I.3.5 [Computer Graphics]: Computational Geometry and Object Modeling—Curve, surface, solid, and object representations