Study on the Digital Reassembly of Yoni Monument Excavated from Cella of Hong Nang Sida, Lao PDR

Abstract

During the dismantling of the cella of the Hong Nang Sida temple in Laos, 100 highly significant Yoni-monument members were recovered as fragmented individual stones. To restore the Hong Nang Sida temple to its former glory, it is necessary to restore the fragmented Yoni-monument members to their original positions. However, the high weight and low mobility of the stones make it difficult to physically reassemble the story members. Therefore, this study utilized three-dimensional (3D) scanning, modeling, and printing technologies to digitally reassemble the Yoni monument. To achieve this goal, optimization modeling was performed to connect the three-dimensional (3D) scanning data of individual fragmented stones, after which each story member was reduced to a 1/5 of its original size and printed by sand printing to evaluate the feasibility of physical assembly. Finally, 3D scans of the Yoni monument assembled using the sand-printing outputs were taken, and all the story members were virtually aligned based on the scan data to complete the digital reassembly. We believe that the results of this study will improve the feasibility and completeness of the physical reassembly by allowing for a full preliminary examination of stone blocks, which would otherwise be difficult to achieve because of the risk of secondary damage or weight limitation. In particular, it is possible to objectively and visually illustrate the geometric relationship between the members of each story, which can be extended to similar stone-based cultural heritage sites. To broaden the utility of the digital-reassembly model, it must be evolved into a historic building information model that links the unstructured data, including documents, photos, and images, obtained throughout the process life cycle.