VR for Cultural Heritage A VR-WEB-BIM for the Future Maintenance of Milan's Cathedral

The work presented here is the final step of a multidisciplinary research project conducted on the Milan Cathedral for eight years (2008-2015). Three main topics, consequentially related, will be here addressed: (i) the survey of the structure, meant to update the old drawings; (ii) the construction of an accurate and detailed 3D model to be used to produce measurements at a 1: 20-1: 50 representation scale; (iii) the development of a Building Information System (BIM) to collect all the data relating to the restoration projects, as well as all information relating to past, current and future maintenance activities of the cathedral. The result of this research project is a complex and accurate digital 3D model of the main spire of the cathedral and of other parts of the building. This model can be visualized, navigated and used by the Veneranda Fabbrica technicians as an info-data catalogue, thanks to a common web browser connected with the remote BIM System Server and the modelling software where ad hoc I/O plugins are implemented. The last step of this long project was to take advantage of the nascent potential of immersive visualization techniques and to transpose the BIM system in a VR environment, thus obtaining two main results. The first was a high-appeal visualization system that allows a virtual visit of the Main Spire of the cathedral, the building's highest part that has been closed to visitors since the beginning of the XX century. The second was the possibility to use this technology to virtually explore the cathedral from a technical point of view: by using an immersive visualization technology, operators can improve their understanding of the structure and obtain real-time information about the state of conservation, including current and past maintenance activities, in a sort of "augmented reality system in a virtual environment".