Shape, Phase, and Source: An HBIM Paradigm for the Documentation of San Lorenzo in Miranda

The paper presents a diachronic HBIM paradigm applied to the complex of San Lorenzo in Miranda, in the Roman Forum, built onto the remains of the Temple of Antoninus and Faustina and stratigraphically connected to the Atrium Vestae. The monument, shaped by transformations from the Imperial age to the twentieth century, is interpreted as a complex palimpsest to be represented through the integration of form, phase, and source. The methodology combines integrated 3D survey (laser scanning, photogrammetry, and georeferencing) with the systematization of historical sources within a relational database structured by Topographical Units and chronological phases. The HBIM model is not conceived as a mere replica of the current state, but as an informational infrastructure that distinguishes surveyed, interpreted, and conjectural data, explicitly linking each geometric element to the origin and reliability of its sources. Transformations are managed through diachronic structuring and parametric operations of volumetric addition and subtraction, preserving the memory of continuities and losses. The extension to the adjacent excavation area —modeled from georeferenced plans and converted into BIM elements through VPL— tests the scalability of the approach in archaeological contexts lacking point clouds. The result is a multi-layered, queryable model conceived as a dynamic archive and epistemological device supporting research, conservation, and heritage enhancement.