The BIM evolution: from the virtual model of the building to the “model federation”, with the main models in the construction industry
Over the past years, the development of BIM technology and the concept of the virtual model have been subject to significant revisions
The BIM revolution: the principle
The first idea was that the goal of BIM technology was to create a single “computing entity” (model) for each building. The model would contain graphic and alphanumeric information and handle everything from a single software application.
This idea later turned out to be unable to handle the complexity and the great amount of information involved. Design is in fact characterized by numerous and distinct skills, often very specialized and conceptually separate from each other.
Additionally, the type od software tool to be used by each designer also became part of the discussion. A Choice often linked to the type of building to be designed.
The BIM evolution: the virtual model
The idea of a virtual model evolves naturally towards an association of multiple models. A model for each specific discipline, capable of seamless dialogue with each other: the concept of “federation of models” is born.
At present, 3 disciplines are generally identified in the construction world. Each discipline corresponds to many models::
• architectural model
• structural model
• plant model
For other disciplines, redefinition of specific geometrical models isn’t necessary, but you can use one or more main models, enriching them with specific information. Consider, for example, the case of:
• the relating cost estimate data
• energy performance calculations
• the schedule of works
• health and safety
• facility management
Of course BIM technology is still evolving. The idea of model’s federation is welcomed, it’s not the same for the identification of the “main models”. Other areas of the construction world need to be considered, for example, infrastructure aspects too. So the proposed list should be supplemented with the specific infrastructure model.
Identifying the main BIM models also means that the software that is called to create them is identified in the same way: these software are now commonly referred to as “BIM authoring” (considered as real BIM work platforms). Software that manages other disciplines is generally referred to as “BIM tools”.
The BIM evolution: how do BIM models interact?
Interoperability becomes a prerequisite for the evolution of the BIM methodology.
It is known that one of the main criticisms highlighted in traditional ways of designing is the loss of information or the generation of errors in passing from one discipline to another.
For these reasons, the construction and optimization of data exchange formats, is one of the key point aspects for affirming the BIM methodology. There are several systems today, but the IFC format, supported by BuildingSMART, is the one used by most software vendors becoming a true standard everywhere.
Even from a buyer’s point of view, the existence of non-proprietary but supported formats by the various manufacturing companies is an important aspect: in this way public authorities can exercise their control over the various stages of design and construction, without having any say in imposing the use of precise software tools. This guarantees the freedom of designers to choose the most appropriate and reliable software tools.
BIM evolution: Data exchange modes
The way in which different models can “overlap” and “talk” to each other is technically guaranteed by data exchange formats. Data exchange formats are constantly updated and refined interms of reliability. The criteria with which the various professional figures build these models are the subject of evolution and which is commonly referred to as the BIM methodology.
Models are made available to the whole development team for appropriate changes and additions, in a collaborative and shared context.