15. Level 0 BIM, Level 1 BIM, Level 2 BIM, Level 3 BIM
The move to ‘full’ collaborative working via distinct and recognisable milestones, in the form of ‘levels’. These have been defined within a range from 0 to 3, and, whilst there is some debate about the exact meaning of each level, the broad concept is:
Level 0
No collaboration. 2D CAD drafting only. Output and distribution is via paper or electronic prints, or a mixture of both.
Level 1
A mixture of 3D CAD for concept work, and 2D for drafting of statutory approval documentation and Production Information. CAD standards are managed to BS 1192:2007, and electronic sharing of data is carried out from a common data environment (CDE), often managed by the contractor. There is no collaboration between different disciplines – each publishes and maintains its own data.
Level 2
Collaborative working – all parties use their own 3D CAD models. Design information is shared through a common file format, which enables any organisation to be able to combine that data with their own in order to carry out interrogative checks on it. Hence any CAD software that each party used must be capable of exporting to a common file format. This is the method of working that has been set as a minimum target by the UK government for all public-sector work, by 2016.
Level 3
Integrated working between all disciplines by using a single, shared project model which is held in a common data environment (see above). All parties can access and modify that same model, removing the final layer of risk for conflicting information. This is known as ‘Open BIM’ (see below), and the UK government’s target date for public-sector working is 2018, although the precise requirements have yet to be determined.
Note that the definition of BIM maturity Level 2 was originally developed as part of the UK Government strategy in 2011. It is also defined in PAS 1192-2, with reference to best practice and the adoption tools and standards. It is also worth noting, though, PAS 1192-2 acknowledges that, given the early stages of adoption of managed methods of working in BIM at the time the PAS was drafted, it can be expected that Level 2 practices will continue to evolve, and that the scope of information sharing and exchange will vary from project to project. Therefore, PAS 1192-2 anticipates that the definition of Level 2 BIM will continue to evolve around the core principles of the shared use of individually authored models in a CDE.
