INTEGRATION OF DIFFERENT TYPES OF SURVEY OUTPUT AND THE INFORMATION ASSET IN A 3D MODEL OF THE CASTELLO SFORZESCO IN MILAN

Abstract. In recent years, the architecture domain, driven by today's digital transition, has been actively exploring the world of digital twins, also thanks to the technological advancement that supports the progress on the issue. Within this context, the present work deals with the wide world of Architectural Cultural Heritage digitization. It aims to obtain a tool to support knowledge, investigation, and management of the built heritage. The research proposes an approach for digital twin development that comprehensively describes the architectural asset, including elements that are no longer present or visible. For this purpose, the three-dimensional model collects the available heterogeneous geometric datum, inevitably characterized by different levels of accuracy. The digitization model designed involves the coexistence of objects belonging to different Levels of Geometric Information (LOGI). All types of data then cooperate in defining the overall geometric information. Therefore, this framework allows for exploiting geometric information from both geomatics digital surveys and historical sources. This system allows obtaining a digital model that includes the different evolutionary phases of architectural assets by providing an overall view of these structures, an essential notion for operating properly on this kind of architecture. The digitization system was tested on a particular case study, the Ghirlanda of the Castello Sforzesco in Milan. The complexity of the property and the richness of the information heritage guided this choice, providing the basis for an appropriate and effective experimental activity.