Collaborative Workflow in an HBIM Project for the Restoration and Conservation of Cultural Heritage

A restoration and conservation project for a building with heritage values requires an increasingly efficient and sustainable methodology. Based on a collaborative 'Teamwork' HBIM (Historic Building Information Modelling) project, this paper aims to describe the technical processes applied to a 16(th)-century historic building to support an open and interoperable workflow between the participating agents. The process is transparent and controllable by operators and disciplines, ensuring direct and continuous access to project data. The study focuses on implementing effective procedures for the identification and classification of heritage architecture. The first stage comprises the analysis of the geometry and materiality of the existing architecture, using data acquisition technologies such as Terrestrial Laser Scanning (TLS) and Structure-from-Motion (SfM) photogrammetry. The information modelling of the historic building begins with a medium level of knowledge, based on the metric survey and enriched by the materiality of the textures deriving from the point cloud. This enables a modelling approach that fits building components to the real geometry of the historic building, considering the deformations and irregularities that occur over time. In the next phase, the BIM project is developed through the analysis of the construction characteristics, materials, and architectural structuring in the historical evolution of the building. The difference between intervening in architectural heritage and new construction lies in the search for the transposition of construction techniques in walls with a long history, thus requiring classification and sectorisation of the various systems used. It is then required to segment the construction systems based on a semantic study of the walls that make up the envelope of the historic architecture. Programming objects in Python within the BIM platform enables the automated identification processes. The method is applied in the identification of the integrating elements of a larger construction entity, such as the stone ashlars of the masonry wall, and the classification by their construction-temporal dating. The main novelty of this research is the use of the object-oriented programming language (OOP), which automates operations based on an open-source structure and allows the operability of cataloguing, classification, and reuse characteristics.