Sviluppo di procedure CAD per la ricostruzione geometrica automatica di una mandibola umana

Authors describe the use of specific CAD procedures that, by means of VBS (Visual Basic Scripting) tools, allow obtaining automatically the geometrical reconstruction, and so the 3D virtual model, of human anatomical parts. In particular, the case study of the external surface reconstruction of a human mandible (related to the cortical bone) is considered, and how to apply it to the cancellous bone also is shown. Starting from CT data, the 3D model (STL format) is obtained. This approximated description of the geometry may be converted to a precise math description by fitting NURBS patches to point data. This approach, adopted by most of Reverse Engineering (RE) software, is able to create very accurate models, but the final model size is usually very large (10-80 MB and more for low/medium complexity objects) and then hard to handle into downstream applications. By adopting the powerful and quite easy to automate NURBS modelling tools available in Rhinoceros® CAD system, and the last commands developed for meshes, authors propose a straightforward modelling procedure that automatically and quickly creates the accurate solid model of the human mandible in a very smaller CAD file size. A comparison with the results coming from commercial software are made to show the quality and the usability of the proposed reconstruction.