Modellazione e rappresentazione digitale per i beni architettonici

Digital modelling and representation of architectural heritage Computer science and digital technologies have led to deep changes in the field of architectural survey and representation. In particular 3D models have acquired an inescapable role in operational practice and as research instrument. Unlike the physical model, the digital one has a mathematical nature; it can be experienced with renderings. The model is an interpretative critical work and a building’s knowledge contribution: accordingly it’s a new document by itself. The ontological binomial of modelling and rendering is referred to the synergic division in the steps that allow the epiphany of the digital model; in this way we have a double aspect of the model: a first signans that has to be conducted to the authentic icon of the signatum. The digital model provides new modalities, times, spatiality and characteristics of vision: the observer can freely surf and zoom the model; he can browse it in a continuous or discontinuous way; he can get into the model, sectioning, measuring and querying it. Moreover the same model can be graphically represented in different ways. Real time renderings allow interactive applications, but the operator is subjected to the roles given by software and hardware systems. The communicative stream given by the iconic textuality of the model, associated to its simple manipulability, browsing and questioning, made the model a powerful and friendly tool for information’s accessing and analyzing. Unlike the textual structures, it allows a simultaneous communication that proceeds according to frames, operated with zooming, intersections, transparency, spatial and temporal jumps. A flux that has in the model’s three-dimensional characteristics his logic. Thus digital technologies for information’s archiving, analysing and management find in the 3D model the support for the construction of architectonical information systems. It’s important the relationship between model’s semantization and database organization. The correlation between the 3D model’s spatial structure – communicatively iconic and with not sequential access modes – and arrays of metadata produces new types of informative systems. In this way 3D models are useful medium for virtual museums, digital archives and architectural informative systems. Two are the modalities of model’s realization: reverse modelling requires the synthesis of discrete data (point cloud) and the semantization is a-posteriori; “direct modelling” proceeds with the construction of the building’s components: it follows an analytical process and the model’s semantization is a-priori. The integration between “direct” and “reverse” modelling can offer interesting areas of application. In conclusion the digital model represents a scientific application of new digital methodologies to the architectural field. The digital model comes to constitute a new objectivity – even if of different nature – that accompany the real architecture: it’s a cultural product, an e-architectural heritage.