Freeform feature fitting is a technique underlying different applications, including reverse engineering, object recognition and conceptual shape design. The latter application poses specific requirements to the fitting technique with regard to speed, robustness and interactivity. On the other hand, the spatial accuracy and the density of the input data can be permitted to be relatively low. We have performed freeform feature fitting to physical shapes using both a high-density mechanical scanning device and a low-cost desktop laser scanner. The performance of these technologies have been compared. The fitting technique is based on direct template matching, where a template is a 3D shape feature under control of 6 placement parameters (defining the ridged body transformation) and a number of intrinsic form parameters. We found that template matching remained reliable even for sparse and partly missing data. A low-cost, high-speed scanner can hence function as a 3D digital shape copier and be a supportive tool for conceptual product design. Limitations and extension of the technology are addressed.

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