The work performed on the Ferrari presents a number of similarities with respect to the work performed on the ‘Vittoria Alata’: it included the 3-D optical digitization of the car, and the generation of a number of polygonal and CAD models.
Fig. 2 shows a view of the whole point cloud obtained by aligning and merging 280 partial point clouds. The step has been performed with the help of suitable markers placed on the surface, given the dramatic regularity of the shapes, and the need to keep the alignment error as lower as possible. Moreover, a skeleton of few, large views (550mm x 480mm), with height resolution of 0.2mm and measurement variability of 0.1 mm has been obtained in the first step. Then, smaller views (370mm x 300mm), with resolution of 0.1mm and measurement error of 0.06mm, have been acquired and merged together using the skeleton as the reference.
The multi-view alignment and the creation of the triangle model at high resolution have been performed by using the PolyWorks software. Then, the mesh has been saved in the STL format and imported into the Raindrop Geomagic Studio environment. Here, the triangles have been edited, topologically checked, and decimated at different levels of compression, mainly using only the automatic tools embedded in the software. Fig. 3 shows one of the most dense models obtained (1.5million of triangles), while Fig. 4 depicts the model obtained after the compression of the previous one down to 10.000 triangles: despite the high compression here applied, the model presents a high level of adherence to the original measured data, thanks to the overall ‘smoothness’ of the car surface. As the last step, the CAD model has been created starting from the triangle mesh of Fig. 3, with minimum intervention of the operator. Fig. 5 shows the rendering of this model (the IGES format is used, resulting into a 120Mbyte file). The prototype of the car has been obtained at the Laboratory of Fast Prototyping of the University of Udine. The process involved the stereo lithography technique. Similarly to the prototyping of the head of the ‘Vittoria’ it resulted into the 1:10 scaled reproduction shown in Fig. 6 (dimension: 370mm x 150mm x 90mm, material: CIBATOOL SL 5190).
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