Intelligent stereolithography file correction

The Stereolithography (STL) file format is a commonly-used format in the fields of Rapid Prototyping (RP) and Telemanufacturing and it is used to describe a 3D model that will be fabricated on an RP machine. Unfortunately, the format is known to be prone to error, and there is a need to investigate ways in which to check a file for anomalies and to correct any such anomalies. This is necessary to prevent the manufacturing of a flawed model, thus saving the resources associated with a defective prototype. The errors that occur most commonly in the format can be divided into two groups, namely stuctural errors and geometrical errors. Structural errors occur on the file itself, where the file is either in the wrong format or does not comply with the STL standard. Geometrical errors are related to the model itself and include missing or duplicated triangles as well as incorrect surface normals due to calculation errors or incorrect triangle orientations. STLComplete, the software prototype developed by one the authors, G.J. van Niekerk, in conjunction with his MSc dissertation, verifies the STL model for flaws and corrects less severe errors as well. Emphasis has been placed on the correction of faults and the presentation of errors to the user. The prototype will be given more attention here.