1 WHAT IS BIM?

1.1 There are many definitions of Building Information Modelling (BIM).

1.2 The RIBA, Construction Project Information Committee and BuildingSmart jointly proposed a definition of BIM for the UK construction industry, as a starting point for discussion and refinement:

'Building Information Modelling is digital representation of physical and functional characteristics of a facility creating a shared knowledge resource for information about it forming a reliable basis for decisions during its life cycle, from earliest conception to demolition.'

1.3 The Department for Business Innovation and Skills refers to:

"a managed approach to the collection and exploitation of information across a project. At its heart is a computer-generated model containing all graphical and tabular information about the design, construction and operation of the asset."

1.4 Is it just for mega projects? Angela Brady, RIBA President, has said:

"Some commentators have suggested that there are financial and skills barriers to the adoption of BIM by smaller practices and that the benefits to small practices may be more limited. However, the RIBA believes that, as happened with the introduction of CAD, a tipping point will soon be reached when BIM will gain widespread acceptance as a transformative technology and working philosophy at all scales of practice. The principles of BIM can be applied to both complex projects with large multi-disciplinary design teams and large numbers of specialist sub-contractors and also to smaller, bespoke projects undertaken in a more traditional manner."

1.5 The BIM Industry Working Group (the "Working Group") was invited by BIS and the Efficiency Reform Group from the Cabinet Office to look at the construction and post-occupancy benefits of BIM for use in the UK building and infrastructure markets. To ensure clear articulation of the levels of competence expected from suppliers, the Working Group referred to four different maturity levels of BIM:

  • Level 0 – unmanaged CAD with 2D formats (e.g. paper or PDFs) used to share information
  • Level 1 – managed CAD in 2 or 3D format, with a collaboration tool providing a common data environment. Commercial data managed by standalone finance and cost management packages with no integration
  • Level 2 – managed 3D environment held in separate discipline BIM tools with attached data. Integration on the basis of proprietary interfaces. The approach may utilise 4Dprogramme data and 5D cost elements
  • Level 3 – fully open process and data integration enabled by web services, managed by a collaborative model server.

1.6 The Government Construction Strategy was subsequently published by the Cabinet office on 31 May 2011. This report announced the Government's intention to require collaborative 3D BIM (i.e. Level 2 BIM) on all projects above a certain size by 2016.

1.7 In reality, the industry is still a long way from achieving Level 3 BIM maturity, not least because of the technological challenges in creating a single manageable BIM model. It is more likely that each party will continue to maintain its own model with a common interface facilitating collaboration and the sharing of information between models. It is also likely to be some time before the lower rungs of the supply chain is ready to receive anything other than paper drawings.

1.8 The shift from level 0 to level 3 BIM has been compared to the shift from drafting on tracing paper to CAD. Others say that the shift is more fundamental than that, because the later shift did not change the output (2D drawings) but simply the delivery mechanism (ie. Tracing paper to PDFs etc). In contrast, the shift from 0 to level 3 BIM requires:

  • Collaborative and integrated working methods and teamwork with closer ties between all designers on a project, including designing trade contractors;
  • Knowledge of databases and how these can be integrated with the building model to produce a data-rich model, incorporating specification, cost, time and FM information;
  • New procurement routes and forms of contracts aligned to the new working methods;
  • Interoperability of software to enable concurrent design activities, for example, allowing environmental modelling to occur concurrent with orientation and façade studies;
  • Standardisation of the frequently used definitions and a rationalisation of the new terms being developed in relation to BIM; and
  • Use of BIM data to analyse time (4D), cost (5D) and FM (6D) aspects of a project.


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