Measured model, theoretical model and represented model: the so called “ Arch of Drusus” in Rome

"The Arch of Drusus is a complex building, stratified over time. It isn’t possible to advance only one hypothesis about its origin, but its several transformations may be given some interpretations. The difficulty lies in the coexistence of two structures, typologically and. chronologically different, in a single monument: an original structure which can be related to a commemorative travertine arch sheathed in marble, dating back to the Imperial Age, which probably had three fornices and a later structure reused in the III century as an aqueduct arch and monumentalized again with the application of decorated architectural elements on the southern façade. In order to provide a graphic description as much accurate as possible from the metric-dimensional point of view and as much detailed as possible in all the elements which form the building, a new survey methodology has been tested. It uses different kinds of systems – instrumental, topographic and GPS, photogrammetric and direct traditional – which complement each other, in order to render a three-dimensional computerized reference model. The analysis process of the monument, made from what emerged from the archaeological analysis, thanks to the carrying out of different navigable models, has been developed making, in the early stage, a represented model subsequently detailed on the basis of the incongruities detected in the survey. -"