Reports about the successful use of BIM are greatly exaggerated. This is how one could describe - admittedly very exaggeratedly - the current situation in the construction industry. It almost seems as if many companies are trying to talk themselves into it; after all, switching to BIM is not exactly cheap. So at least the topic has to "serve" for marketing purposes.
Not that I am being misunderstood here: I am fully behind the endeavor and the idea of BIM. My definition may not coincide with that of other consultants or experts - but in principle, the industry is pursuing a laudable goal with BIM. If not, and this is where the criticism lies, the methods and approaches are sometimes extremely memorable.
In the following, I would like to address an aspect that not only I find disconcerting, but which also puts off many "BIM newcomers", namely the "all-or-nothing" problem.
"All in" or "peu-à-peu"?
More, more precise, faster, more centralized. "With BIM, everything must be stored in the model". "Everything must be designed as three-dimensionally as possible". Such claims are bound to fail.
I therefore advocate a concept that I have called "minimal BIM" here. As a newcomer, you start with the smallest possible implementation of BIM, and the IFC format in particular allows a lot of leeway here, as we saw in an earlier article . Basically, it is not necessary to create a three-dimensional model just to have it in IFC format. So why should an owner or building manager go to all this trouble? Any information that is entered here or translated from another system carries a certain risk of transmission error.
When using BIM for the first time, those involved must therefore ask themselves the question: "How can we set up a system that is as future-proof as possible with the least possible change effort?". If only overview plans and area lists are required, a 3D model is not necessary. Not even for information on windows or doors. The position in the building can also be specified without a 3D geometry (see here). Building services systems can also be documented without geometries. Geometric modeling should be the last step (at least when considering existing buildings; however, such an approach can also help in the preliminary design phase).
There is therefore no reason not to use a three-dimensional representation at the beginning; on the contrary: the IFC schema explicitly offers methods for saving reduced representations adapted to the data usage in the IFC file. For overview plans, for example, this would be the "Footprint" geometry; for static models, the "Surface3D" geometry (as plates and slices), to name just two examples.
Less is more
Less is definitely more here. You have to be able to rely on the information contained in a building data model; otherwise the system is useless. Incorrect information is displayed in the same way as correct information. Missing data can at least be searched for elsewhere.
I am aware that such an approach is fundamentally different from the conventional wisdom. BIM is too often still seen as "3D + information". But it is much more than that, and yet much less. It is the digitalization of our built environment, its surroundings and the associated processes, products and people. As soon as a "thing" (or person) has a unique ID, it can be reused, measured, managed, planned, tracked and optimized (in the case of people, of course, this sounds strange, but nonetheless it is possible).
Completeness is not a primary goal; it is about continuous further development. 2D IFCs? Why not! Geometry-free system representation of building services installations? Building management including floors and rooms without any geometry? IFC would not be a problem. And if 3D geometry is needed one day? That's no problem either. The ID and information are already there, the appearance just needs to be added.