10 December 2012
There has been so much written about what BIM means I hesitate to add any more. Yet there still seems to be an enormous amount of variation about what it means to different people.
People may argue there is already a clear definition of BIM, but the reality is everyone has a different version of that definition defined by their own area of expertise.
Let's start with Wikipedia's definition:
"Building information modeling (BIM) is a process involving the generation and management of digital representations of physical and functional characteristics of a facility. The resulting building information models become shared knowledge resources to support decision-making about a facility from earliest conceptual stages, through design and construction, through its operational life and eventual demolition."
Sounds pretty good. A broad, all inclusive description, it includes the 5 'stages' of a facility's life.
But in deeper discussion about actually doing BIM I'm finding the people involved in those 5 stages have differing views on what is important in BIM implementation, and hence their practical view of what BIM means.
Those involved in operations (FM) believe IFC is quite adequate for BIM and don't realise IFC's inability to capture intelligence makes it useless during design. Those involved in design don't appreciate that creating lists and schedules separate from the BIM file adds to the work load of those involved in construction and operations (FM).
There are also some technical confusions in definitions of BIM. One is the myth of the single shared Model. Technically implementation of BIM doesn't require this. Information about a facility can come from multiple models. Yet the Wikipedia description falls into this trap:
"... BIM enables a virtual information model to be handed from the design team to the main contractor and subcontractors and then on to the owner/operator; each professional adds discipline-specific data to the single shared model."
Another is that BIM is only about information. The American Institute of Architects has defined BIM as "a model-based technology linked with a database of project information". But truly BIM software is capable of more than just information, it also has intelligence. It knows a wall is connected to a floor and ceiling, so maintains that relationship even when that floor or ceiling moves. It knows what duct, dampers and AHU unit an A/C register is connected to.
A third area of confusion is defining BIM as the work processes that are possible, or at least easier, to implement when using BIM. The classic is Integrated Project Delivery (IPD), pushed by many as the 'only' contractual arrangement where BIM can be 'truly' utilized. Yet IPD does not require BIM. In the late 1990's I was involved with a project in Australia done under an 'Alliance' contract, effectively IPD. That project was done entirely with CAD. No-one even mentioned BIM as a possibility, let alone a necessity.
So the way BIM is being defined is either too broad, trying to include the many players in BIM; or too specific, including technical descriptions that don't hold in all situations; or about something completely different, that doesn't actually require BIM at all.
So where is the term BIM come from? What did it originally mean?
I won't repeat what has been covered elsewhere, a good reference on the description and history of BIM is at the Architecture Research Lab.
But I have always thought BIM meant the use of the power of computers to hold information, as opposed to traditional practice where it is held in various people's heads and scraps of paper (called 'drawings').
I used a similar term back in 1998 to describe a method of using CAD to hold information about a building, Using CAD to Model Buildings. I called this a CAD Information Model (CIM). Utilising standard CAD meant it was very limited, and being for architects and not computer programmers not very sophisticated. It has only quaint historical interest now, but I still maintain that the base thing we are trying to achieve, before any of the other things, is to use computers to manage and maintain information about a building. The only thing I would add is that BIM also includes the managing of relationships between information, the intelligence I spoke of earlier.
So what does BIM mean to me?
I am reluctant to add yet another definition, but to be fair to my readers I feel I should make a clear statement about what I mean. Here goes:
Building information modeling (BIM) describes the use of digital technologies to create a virtual representation of the information and relationships required to undertake the conception, design, construction and operation of a built facility.
I would further contend that the term BIM only be used for what BIM stands for; Building Information Modelling. NOT integrated project delivery; NOT facility management data storage; NOT life cycle design; NOT work processes; and NOT a single repository for all information about a building.
I believe these are all valid and worthwhile purposes, but let's give them their own terms and acronyms.
Let's keep the meaning of BIM simple and to the point, and stop the confusion.