“BIM for the existing world”, modeling AEC reality through high definition surveys

Building Information Modeling is considered by the scientific literature as an emerging trend in the architectural documentation scenario, as it is basically a digital representation of physical and functional features of facilities, serving as a shared knowledge resource during their whole life cycle. BIM is actually a process, in which different players act sharing data through digital models in a coordinated, consistent and always up to date workflow. This way, BIM tools were originally meant to ease the design of new architectures, generated by parametric geometries connected through hierarchical relationships of “smart objects” (components self-aware of their identity and conscious of their interactions with each other). However, this approach can also be successfully applied to what already exists: TLS (Terrestrial Laser Scanning) or digital photogrammetry are supposed to be a strategy in which BIM, relying on its own semantic structure, is explicitly used in the representation of existing buildings. Some progresses in the development of this attitude, especially related to sites belonging to the Cultural Heritage, are included in this packet. This presentation, which is used by the author for his Architectural Computer Graphics and Advanced Virtual Modeling courses at the University of Bologna, School of Engineering and Architecture, is an introduction to the use of BIM combined with surveys, highlighting critical aspects and advantages deriving from the application of parametric techniques to the real world domain representation.