The devil is in the detail

BIM models are an excellent tool for quantity takeoffs, clash detection and, over the long term, will provide a consistent record of the building's construction history to enable more efficient renovation or modification. But of course all of this depends on the quality of the input data in the first place.

This is where problems can occur. For example, we have found during trial runs that many elements of the initial model have been detailed in only 2D or indeed are entirely missing. This hampers the ability to create detailed outputs. It doesn't break the process entirely and we can work around it, but for the most effective deployment of BIM across a project's life it's essential to agree on the level of detail that will be required, with an understanding that it is much more time-consuming to change that detail retrospectively.

For example, the image below shows the steel framework of the proposed building. However in this instance the architect has used a single reference for ALL beams. Without the detail of each beam type it is impossible for us to use the BIM software to calculate the amount of steel that will be required. If each beam type was referenced with the specific detail of length and surface area we could produce an accurate take off. As it stands we could only produce an estimate in total linear metres, which would leave questions about the total volume of steel required. Here a little more work at the input stage would have yielded greater dividends further down the line.

Correcting these issues does mean more effort initially for the architect, but in time this should be recoverable by higher fees once the client realises (or is educated) about the benefits to them in terms of fewer delays, errors or disputes during the construction phase.

What this illustrates is that we really do need to work together at the start of every BIM project to define the deliverables from each of the partners. This will ensure that we achieve the best possible use of BIM and will also allow us collectively to accommodate organisations at different stages of the BIM maturity curve, essential as we will inevitably move at different speeds according to our individual resources and business pressures.