SCAN TO HBIM FOR COMPLEX REFLECTIVE METAL ARTEFACTS. 3D DIGITISATION AND RESTORATION

Abstract. 3D digitisation of metal artefacts, regardless of the use of passive and active sensors and low or high costs technologies (digital photogrammetry, laser scanning, structured light 3D scanning) represents a challenge above all due to the high reflectivity, absorptivity and scattering of the materials, as documented by the specialistic literature (Frost et al., 2020, Hallot et al., 2019, Nicolae et al., 2014). Regardless of the size and material, mobility and immobility of the elements, artworks preservation and restoration involve intervention and collaboration between different specialists, such as restorers, conservators, diagnosts, architects, surveyors, modelers, archaeologists and art historians. This multidisciplinary process requires a virtual container aimed at systematisation and sharing of digital products and data deriving from heterogeneous diagnostic and applicative activities (Farella et al. 2022, Ferretti et al. 2022, Fiamma 2019). According to these premises, this paper shows a low-cost Scan to HBIM process aimed at digitisation of a complex reflective metal artefact, an altar frontal composed of several pieces characterized by different metal materials, functions, sizes and topological complexity (level of decorative detail). Therefore, this system is approached considering its individual components and its morphological-compositional complexity as a unique piece. The entire process has been tested both in research and didactic field, using low-cost tools for acquisition (cameras, smartphones, computers) and software open source for processing, filtering, editing and sculpting digital photogrammetric copies of highly reflective artefacts.