Learning by modelling in H-BIM environment to develop a framework for restoration. Application to the stone cladding of Casa delle Armi of Luigi W. Moretti in Rome

• The H-BIM modelling workflow is a way to gain new knowledge on the historic building. • “Learning to model” and “learning by modelling” as a protocol for H-BIM modelling. • A historicised H-BIM model makes more effective restoration/maintenance projects. The approach to architectural restoration within a BIM environment, i.e. the so-called H-BIM, although now essentially mandatory, still presents application challenges and methodologies that are not yet fully recognised. In this context, the restoration of Modern architecture is of particular interest, given the relative proximity in time of the construction of the buildings and the specific deterioration problems that these constructions typically face in an accelerated form. The use of digital tools, which such modelling entails, not only effectively supports the restoration process, but also significantly interacts with the study and knowledge of the building. This article focuses on the increase in knowledge associated with the modelling process. The aim is to demonstrate how the understanding of the building necessary for creating the model (learning to model), in addition to external bibliographical or documentary sources, as well as survey and in situ analysis, is increased the modelling activity itself, according to a process of “learning by modelling”. The methodological proposal is presented and applied on a particularly significant case study: the “Casa delle Armi”, a building designed in Rome by the architect Luigi W. Moretti in 1933–36, during the Fascist regime. The building is entirely clad in thin slabs of Carrara marble. This marble cladding was the first and archetype of many similar applications carried out in the same years, and has suffered considerable deterioration, for which a particularly complex restoration process is currently underway. In this article, the procedure used to obtain a historicised H-BIM model of the façade is described and discussed, as well as the advantages and the challenges associated with modelling. Furthermore, the limitations and possible developments of this approach are highlighted, emphasising the knowledge gained from the convergence of the two operational lines (learning to model and learning by modelling). In the appendix, a brief reconstruction of the life phases of the “Casa delle Armi” is provided, integrating the outlined method with documentary and bibliographical information.