From the digital to the physical model. Case study in the yard of the Milan cathedral.

Metric representations of three-dimensional objects, namely real-based models, allow complete analysis of objects geometric shape and metric computations (volumes, exposed surfaces) that are hardly executable without a three-dimensional support. They also let virtual operations as virtual navigation and inspection, structural analysis and dynamic simulation. Threedimensional models at the real scale can be used to speed up the operations of substitution of damaged parts. It is a very important task in the time consuming management procedures of the Milan’s Cathedral, where extremely deteriorate marble part are normally substitute in order to restore the structure and to ensure the safety of the Cathedral. A real based model can be also used to make a scale reproduction of objects that are not visible to the public. This can assume great value in the field of communication and of the fruition of artworks. In the yard of the Milan Cathedral are mixed the centuries old tradition ‘in making’ with the most modern techniques of threedimensional survey and modeling. The complexity of the Cathedral building constitutes an excellent test field for the research on new techniques of 3D survey allowing to measure and to model complex objects that up to a few months ago were impossible to be acquired in a traditional way; an example to all: the “Madonnina”.