Noncontact restoration of missing parts of stone Buddha statue based on three-dimensional virtual modeling and assembly simulation

Abstract

Three-dimensional (3D) digital technology is an essential conservation method that complements the traditional restoration technique of cultural artifacts. In this study, 3D scanning, virtual restoration modeling, and 3D printing were used as a noncontact approach for restoring a damaged stone-seated Bodhisattva (stone Buddha statue). First, a 3D model with an average point density of 0.2 mm was created by integrating the fixed high-precision scanning of the exterior and the handheld mid-precision scanning of the interior excavated hole. Using a 3D deterioration map of the stone Buddha statue, the area of the missing parts was measured to be 400.1 cm2 (5.5% of the total area). Moreover, 257.1 cm2 (64.2% of the missing part area) of four parts, including the head, surrounding area of the Baekho, right ear, and right eye, for which symmetry was applicable for modeling or there could be ascertainable historical evidence for the total missing parts, was selected for restoration. The virtual restoration of the missing parts of the stone Buddha statue was performed using a haptic modeling system in the following order. First, the location of the three fragments detached from the head was determined. Next, a reference model was selected, and its symmetrization and modification with respect to the original model were conducted. Further, estimation modeling and outer shape description were achieved through historical research and consultation with experts. The heuristic-based assembly suitability of the created virtual restoration model (461 cm3) was verified by design mockup printing and digital–analog simulation. In particular, to address assembly interference, the interface surface was modified and reprocessed several times. Accordingly, the volume of the final design mockup decreased by 5.2% (437 cm3). Photopolymerization 3D printing technology was used for the actual restoration of the stone Buddha statue, and considering the surface roughness, the layer thickness of the material used for restoration was set at 0.10 mm. Finally, the surface of the printed output was colored to prevent yellowing and joined to the missing parts of the stone Buddha statue. This study presents a remarkable case of shifting from the traditional manual-contact method to the contactless digital method for restoring artifacts and is expected to largely contribute to increasing the usability of digital technologies in the restoration of cultural artifacts.

Convergence Modeling and Reproduction of a Bigyeokjincheolloe (Bomb Shell) Based on Three-dimensional Scanning and γ-ray Radiography

“…In addition, the lid was modeled using the numerical data recorded in the condition investigation and its size alone was adjusted to fit the studied bomb shell (Kim and Huh, 2020). 2019b; Jo et al, 2020a;Lim and Choi, 2020;Higueras et al, 2021). In this study, the modeling results of the bomb shell were output to the 3D printing technology using the material extrusion method (Ultimaker 3 Extended, Ultimaker B.V., NLD).…”

Copyright Protection of 3D Digitized Artistic Sculptures by Adding Unique Local Inconspicuous Errors by Sculptors

“…In recent years, 3D scanning has become a widespread technique for collecting 3D images of cultural heritage artifacts, in the areas of small historic objects [40][41][42], sculptures [43][44][45][46], rooms [47,48], or large buildings and entire architectural sites [49][50][51][52]. Structured lighting technology is suitable for the digitization of cultural heritage objects because it is a contactless method for 3D digitization [53].…”

RestArt method: innovative high-precision mechatronic-based procedure for fragmented stone statues restoration

“…In recent years, technologic innovation and advances in 3D virtual reconstruction, visualization and computing permitted high-precision virtual reconstruction of fragmented objects [1][2][3][4], but practical reassembly of real parts remains a challenging task. Of course, virtual reconstruction is very helpful to guide the restorer in manual procedures [5].…”