Bridging the symmetry-related gap between physical and digital sculpting by application of reverse engineering modeling

Abstract

© Faculty of Mechanical Engineering, Belgrade. Nowadays 3D technologies are integrated into all aspects of modern lives. This integration of 3D technologies paved new paths for further expansion of other fields, most recently the field of arts. In this paper bridging the symmetry-related gap between physical and digital sculpting by application of reverse engineering modeling was presented. This approach enables artists to express their art in physical 3D object form and then transfer it into a digital world in order to satisfy various prerequisites (here, the final 3D model is to be ideally symmetrical). In order to describe this process, one case study is selected. With the use of close-range photogrammetry based on structure from motion, as a 3D digitization technique, a physical 3D model of a human head - manually sculpted in clay was digitized. In order to obtain a final physical or digital 3D model of sculpted head and to make it symmetrical, the symmetry analysis and correction was performed. Namely, by comparing digitized 3D model with its idealized 3D model (that was created based on symmetry-correction), symmetry analysis was carried out using computer-aided inspection. The results showed critical regions of the physical i.e. its digitized 3D model that, because of having no acceptable levels of dimensional deviations (regarding ideal symmetry), it must be corrected/minimized. This can be performed either by manual re-sculpting of the physical 3D model, or by modification of digitized 3D model (if there is no intention to use idealized 3D model for subsequent CNC-fabrication as an example).