San Marco 3D is a great project that aims to document the entire Basilica, through a digital model, rich in information and useful to the managing institution of the property. The Basilica of San Marco in Venice is a unique case in the field of Cultural Heritage, as it is a building site always active for its maintenance and preservation. For this reason, in 2013 the Prosecutor of the Basilica of San Marco commissioned the construction of a 3D model of the Basilica to be used for the creation of an optimized management system, a HBIM. The model meets the required accuracy of the 1:50 scale and includes, in addition to the geometric description, a description of the mosaic and marble surfaces of the Basilica through high-resolution orthophotos that are essential for the restoration of floor and wall mosaics.