3D or not 3D: that is the question

Do you have issues with subcontractors providing 2D designs when you’re working in 3D? Michael Lehane discusses some recent experiences.

It would be fair to say that behind the majority of today’s construction work, 3D modelling is being used to ensure projects are delivered as efficiently as possible. Here at Digital Engineering Studio, we endeavour to employ all modern technologies to provide such services to the highest standard; however, many companies still limit themselves to 2D design.

In some scenarios, 2D drawings are more than adequate. A problem materialises during the construction stages of a project if it is modelled predominantly in 3D with a handful of disciplines significant to coordination only able to work in 2D.

Some recent examples here at Digital Engineering Studio include a branded hotel model we developed on behalf of a building services consultant. During the technical design phases of the project, an independent furniture, fixings and equipment practice was only able to provide 2D CAD layouts to incorporate into the model. It was far from the end of the world; however, from a BIM and design perspective referring to external CAD/PDF files to confirm certain details added a considerable amount of time onto the workload, along with the potential for error.

Late changes in 2D

A more troublesome example – and the inspiration for this piece – involved a school model we developed to Stage 5 on behalf of a contractor. We received a detailed Stage 4 model and began to incorporate the necessary components procured at Stage 5. Late on, the contractor subcontracted a specialist to provide the sprinkler design; however, this company was unable to provide or use any 3D information. This resulted in an additional level of work for us modelling from their 2D CAD layouts and feeding back in-depth evidence of why certain routes weren’t feasible, etc.

The sprinkler design team would then push back on certain parameters to ensure regulations were met, and we were then responsible for updating the model and re-issuing drawings with the whole process adding extra time to the scheme and coming close to triggering delays on site.

I was curious to find out if others had similar experiences and whether they approve of 2D drawings for coordination, specifically when the other disciplines provide 3D models; so, I took to LinkedIn.

Q: During coordination of a BIM project, what are your thoughts on subcontractors providing 2D layouts?

Results – 170 votes in total

  • Acceptable: 52%
  • Unacceptable: 37%
  • Only use BIM-ready subbies: 11%

As you can see, some disagree with the inclusion of 2D in a 3D environment; but the majority believe it’s acceptable. Judging by the comments, the results may be slightly inaccurate as some interpret the question to be “should 2D exist at all” rather than the intended “should 2D be used for services that impact coordination”.

From experience, another potential reason for the result may be the absence of communication between certain disciplines and the site teams who likely resolve any issues caused by coordinating with 2D data – a divide BIM was partly introduced to bridge.

With the results far from unanimous, it may also be that the experience we faced is relatively rare and most projects run smoothly when relying on 2D information for coordination; although, the fact remains that 2D doesn’t consider necessary real-world constraints that will eventually require consideration during the construction process.

Building information modelling was introduced in the UK over a decade ago to benefit and help unify the construction industry. While this article isn’t put together to vilify any company still outputting 2D drawings, I do believe software today enables users to create 3D models in similar timescales, so urge anyone reading to consider updating and upskilling or partnering with an outsourcing specialist, as the impact down the line can be far more costly and time-consuming.

Michael Lehane is BIM technician at Digital Engineering Studio.

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  1. I think its important you put this into context, your headline refers to coordination as the “purpose” your seeking to solve and then you use furniture contractor as your example of non 3D capability! This impacted the design coordination how?
    Even sprinkler systems aren’t necessarily a major blow depending on the ceiling designs.
    Focus on the end goal and decide for each procurement early what is required. I dont trust 3D designs that are copies of the 2D and never use that 3D based information because its not a carbon copy and could be out of sync or date.
    I would say this is more a process problem than a capability issue in these examples.

  2. Hi John,

    My original article title ‘Cadapt or Die’ was changed by the publisher so I appreciate your point (lighthearted play on words). The aim of the article is to encourage more use of 3D in the industry.

    Regarding the furniture, fixings and equipment example mentioned, the company were designing feature ceilings with various heights and acoustic elements. Bar areas / large kitchens with various elements requiring mechanical services.

    Regarding sprinkler systems, why risk a ‘blow’ at all when we have the capability to iron out the issues before it reaches site? This scenario had 100mm pipe runs down tight corridors with large branches into rooms either side. As explained, the 3D version of the sprinkler design was developed using the 2D drawings as a basis (head positions), not a tracing exercise etc.

    I agree RE processes.


  3. I note the concern about the headline: ‘coordination’ removed! Ed.

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