Building Information Modeling and real world knowledge. A methodological approach to accurate semantic documentation for the built environment.

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 (not a software, as someone indicated), in which different players act sharing data through digital models in a coordinated, consistent and always up to date workflow, in order to reach reliability and higher quality all over the construction process. 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 the first abstraction step in a methodology proposal intended as a scientific strategy in which BIM, relying on its own semantic splitting attitude and its topological structure, is explicitly used in representation of existing buildings belonging to the Cultural Heritage. Presenting some progresses in the development of a specific free Autodesk Revit plug-in, nicknamed GreenSpider after its capability to layout points in the digital domain as if they were nodes of an ideal cobweb, this paper examines how point clouds collected during high definition surveys can be processed with accuracy in a BIM environment, highlighting critical aspects and advantages deriving from the application of parametric techniques to the real world domain representation.