Digital Reconstruction for the Analysis of Conservation State: The Transmission of Historical Memory of St. George and the Dragon Tile in San Michele Basilica Facade

The case study presented describes the experimentation of 3D digital reconstruction carried out on a portion of the facade of San Michele Basilica in Pavia. The facade is characterized by numerous sandstone bas-reliefs, that have been deteriorating throughout the years, composing narrative cycles of historical kings and myths of the Lombard Kingdom. Starting from acquisitions carried out on the field and through the study of the historical conservation of the decorative tiles, researchers worked to create a digital model representing the actual state of conservation of the St. George and the Dragon tile. Such model has been compared to the one based on historical images and surveys carried out during the past century. The goal is to obtain an information system for conservation management protocols and for dissemination of this disappearing heritage. The method applied to the pilot case consists of geometric and material survey, documentation of the state of conservation and analyses with non-invasive techniques, leading to the three-dimensional reconstruction of the tile. The result allows to perceive shapes of the tile that are now illegible and understand the volumes as they should have been. The different conservation status of the tile can be appreciated on the physical object or in virtual mode, through VR system and FDM 3D printing.