In the field of mechanical engineering, reverse engineering is usually associated with 3D digitization. It is a process of transforming an existing object into a digital model, which can be imported into CAD systems. Scanned polygonal data are converted to volumes or surfaces. However, methods of reverse engineering produce not only a digital copy of an existing object. The data can be used also for improvement of the original object in terms of design optimization, analyses, inspection or for the purposes of other software applications.
3D digitization is a key operation when converting polygonal data to CAD data. Quality of the obtained data is crucial for the overall accuracy of generated surfaces. We use German 3D digitizer Atos Triple Scan 8M for this purpose. Exchangeable optical system enables us to digitize the objects from 1 mm up to several metres. Resolution of the scanner varies from 61 points per mm to 1 point per mm. To improve accuracy when digitizing large objects (approx. 10 metres), we use one-camera photogrammetry system TRITOP. This system also analyses and assesses deformations in discrete points, e.g. deformations due to temperature changes or stress may be observed. We use software Tebis to create high quality 2D data. This software is suitable not only for making the models, but also for design and simulation of machining operations. When making the model, it is important to find a compromise between smoothness of surfaces and the deviation from the original object. According to the requirements, we are able to create either high quality surfaces models (smooth models with curved connection of the surfaces) or very accurate models (deviation from real object is from tenths down to hundredths of mm).