A BIM dimensional rift

Coming from a technology industry, Building Information Modelling (BIM) has a large amount of technical lingo, acronyms and abbreviations. But the poor use of language is increasingly causing confusion and poor outcomes.

4D, 5D, 6D & 7D: When software vendors jumped on the BIM bandwagon, their marketing teams went into overdrive creating wording to excite customers. Flowing on from 2 dimensional (2D) drawings and 3-dimensional modelling (3D), they came up with 4^th (time) and 5^th (cost) dimensions. Snowballing down the BIM hill, enthusiasts decided the 6^th and 7^th dimensions were an obvious addition. In further digging, I've come across BIM titles up to the 11^th dimension!!!!!

So what does 4D, 5D, 6D and 7D mean? How is it defined………..?

The first problem; depending on what source you read, the meaning is slightly different!!!!!

4D is linking a construction programme (work schedule) to the model (or part model), to generate a construction programme (time) simulation. These simulations may be very simple (just showing basic staging) or extremely detailed (including all work tasks). 4D “may” include Clash Detection of the construction programme (including temporary works), and it may also be used to help in construction scenario planning.


5D is adding cost on top of 4D, i.e. integrating costs into the construction programme simulation,
or it may be the extraction of quantities from the model, and link them a costing table;
or potentially, a combination of both. There are other uses of the BIM for assisting in cost management (e.g. value engineering, temporary works costing and construction scenario costings).


6D is using the model for ongoing facility management (Life-cycle management),
or it may be using the model to analyse sustainability and/or environmental impacts. The use of this term depends on which source you look at. Some web examples: 
Link 1
Link 2

7D is facility management, and/or asset management. However again, precisely how it is used in facility / asset management is not defined. It may be simply as a record model for future construction works, or it may be directly integrated into one of many facility / asset management applications, to track ongoing facility operations and maintenance. Potentially, there are many ways a facility/asset manager could use the BIM.

So, are you confused now? There’s more!

Introducing Physics; it seems BIM enthusiasts have little grounding in physics. 4D to 10D has been already allocated:

4D is space-time. I'm not a theoretical physicist, but in my understanding 4D is a key item in the Theory of Relativity (Einstein 1915). In this theory, time is not a constant, and can be altered by velocity (i.e. travelling the speed of light). When your velocity is close to the speed of light, time slows down. Travel faster than the speed of light and you start to go backwards in time.

5D to 10D, are used within String Theory (1969), to explain physics before the Big Bang (i.e. the universe creation). It includes multi-universes and the potential of travelling between them.

Utter Confusion: Thus, when we add up all the above, if people are to use the BIM terms; 4D, 5D, 6D & 7D, they are unknowingly; regurgitating  software vendors marketing teams, calling up deliverables with little to no definition, and using words which have already been taken by the science world.

The Point: One of the greatest challenges our industry has, is a clear understanding of BIM; how it can be leveraged and how it can be requested/specified. Even if we ignore all of the above; using words which are vague, un-defined and technically incorrect is not helping anyone. In moving forward, BIM language should be clear, concise and understood by all parties. After all, a key philosophy of BIM, is better communication.