Building archaeology informative modelling turned into 3D volume stratigraphy and extended reality time-lapse communication

This paper describes the case study of the damaged church of St. Francesco in the Arquata del Tronto (Italy), struck by the earthquake in 2016. The municipality commissioned the research to support the preliminary design of the preservation plan. The first digitisation level has been performed from the richness of surveying data, acquired from static and dynamic terrestrial laser scanning (TLS), as well as photogrammetry; overcoming challenging constraints was necessary due to the scaffolding covering the surfaces. The geometric survey allowed authors to acquire massively geometric and material information supporting the three-dimensional (3D) volume stratigraphic and the creation of the Heritage Building Information Modelling (HBIM). The authors propose a shift from the Geographic Information System (GIS)-based analysis of the materials toward spatial HBIM management. Building Archaeology is turned into HBIM 3D volume stratigraphy, overcoming the bidimensional (2D) surface mapping, in favour of a 3D understanding of direct and indirect sources. Material mapping is added to HBIM 3D volume stratigraphy, and each stratigraphic unit (SU) has its proprieties. The 3D volume stratigraphic database has been designed to collect the data on the unit detection at three levels (direct sources data collection, indirect data documentation, the relation among the BIM object elements). A common data environment (CDE) was set up to share the 3D volume informative models that can be accessed, including all the information gathered. The knowledge transfer using the eXtended Reality (XR) potentiality improves citizen and tourist experience, enhancing the comprehension of difficult concepts like the SUs to support a better critical 3D reconstruction. It includes the phases of construction across time-lapse documentation that validates related information within the building archaeology informative models leaving spaces to the uncertainty and documenting the relationship established so far thanks to the direct and indirect sources. The result obtained is a live digital twin that can be continuously updated, which justifies the costs and time demand of HBIM despite 2D drawings.