A yard of the future: the main spire of Milan Cathedral

The work is the result of a long research process that led to the realization of a BIM system starting from photogrammetric survey. Subject of the investigation is the main spire of Milan Cathedral. In particular, the work has evolved over four years following step by step the evolution of 3D survey and modeling methodologies with particular attention to the “image based approaches”. This has enabled to produce a complete model of the spire and to create a prototype of BIM useful to manage the huge 3D data together with images and information to be used during the restoration works. The proposed research was to explore the survey technologies in order to find the most appropriate, fast and low costs methodologies to virtualize a complex architectonic structure. Today (2013) the whole object 'Spire' is represented by a detailed and rich 3D model that represent all marble constructive blocks, ornaments and decorations and also structural elements. The last research activity was aimed to create a WEB platform in order to visualize the model online and use it as base to collect information. The main aim was to converting the 3D model from a static representation to a dynamic information tool capable to collect multi-disciplinary external data and to document changes over time. This lets to describe both the ‘status quo’ and the 'history' of alterations(from CAD2D to BIM 4D). The continuous transformations and interventions of the structures can be visualized, explored and investigated directly on the 3D model. The process of implementation of BIM is carried out in close contact with the “Veneranda Fabbrica del Duomo” in order to identify the main processes and to develop an integrated system that helps to support step by step the restoration workflow and the ordinary and extraordinary maintenance of complex objects as the Spire. In particular attention was paid in creating a user friendly system to facilitate the collaboration between operators (in particular yard- technical office) that normally are not expert in 3D technologies and database management. The system is built following the international standard both in the visualization module and in the information management part. In this way it can be easily updated because compatible with future technological development. Moreover all the BIM is built using free or low cost libraries. The visualization part and the connection tools with the modeling software are, in this way, ready to adapt the system for general CH cases. The database system is created ad hoc for the purposes of the Veneranda Fabbrica and adapted to their way of working. The goal was in fact to create a BIM process that was useful and generally applicable in the field of cultural heritage; then a standard system easily adaptable and customizable to the many and different cases that arise in this field