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BIM: construction first needs to catch up with 3D CAD

23 October 2017

BIM can only take off in the UK once construction completes its long overdue adoption of 3D CAD, argues Robin de Jongh of GCA Consulting in this month’s ICE Civil Engineering journal.

BIM: construction first needs to catch up with 3D CAD

Headline statistics from the NBS National BIM Report 2017 (NBS, 2017) suggest all is well with the UK government's push to adopt building information modelling (BIM) across the British construction industry. However, closer examination of the report shows not all is as straightforward as it seems.

Take for example that only 19% of the report's respondents think the construction industry is delivering on the government's mandate for fully collaborative three-dimensional ('level 2') BIM by 2016 (Cabinet Office, 2011). This is at odds with the report's foreword, which states, 'BIM Level 2 looks to be well established; the normal way for most practices to carry out design work' (NBS, 2017: p. 3). Can both of these can be true?

Personal experience of working in civil and structural design and talking with a broad range of construction clients suggests BIM is largely being ignored rather than becoming the normal way to carry out design work. The author also regularly speaks with BIM software vendors – they too confirm BIM has not been adopted as they had hoped, apart from a few notable exceptions.

A question of semantics

The disparity would appear to lie with semantics. BIM software outside the built environment is simply called three-dimensional computer-aided design (3D CAD), or just CAD. Examples are Solidworks, Solid Edge, Catia and Inventor. These are as powerful as more construction-focused 3D CAD software, such as Revit or Tekla, and some are a good deal more mature in software development terms – yet the latter have come to be termed (only within construction) as BIM.

BIM means the process of creating and using a shared CAD model and database which contain sufficient information to plan, construct and maintain a project throughout its life cycle. It embraces the entire gambit of quality assurance standards, process implementation and management, drawing production, people management, data-sharing formats, strategy and technology. Software is just one part of BIM.

Returning to the NBS survey, it can be seen that 71% of companies are implementing 3D modelling of some kind (i.e. 3D CAD), but only 38% are using PAS 1992-2 (BSI, 2013), the standard for level 2 BIM. It would seem that many of the 62% who say they are using BIM actually mean they are using 3D CAD.

An obsession with software

Looking at the bigger picture, it is interesting to see what people are looking for online rather than what they say in survey questionnaires. According to Google Trends, both Solidworks and Revit attract very similar levels of interest.

However, on leading job search website, demand for Revit skills is four times that for Solidworks. This points to an unnaturally high level of desire to adopt Revit among employers, who may see it as a proxy for BIM.

Far from a BIM revolution, perhaps the construction industry is simply in the process of discovering the benefits of 3D parametric CAD. It is experiencing the same CAD awakening other industries had over a decade ago.

Only by recognising this distinction can the true level of BIM adoption be identified and work begin towards a better outcome.

This article is based on an article published in the November 2017 issue of Civil Engineering.