Why Clashes Exist in BIM At All with Rubens Lage Lopes

This newsletter has been prepared for a recent episode recorded for the Digital Construction Podcast, featuring Rubens Lage Lopes, BIM Information Manager of the Grangegorman Development Agency.

The best career advice Rubens Lage Lopes ever received was to go slower. He has a lot of ideas and a habit of moving fast, and someone told him to pace himself.

In construction that advice sounds unusable. Deadlines are short and nobody gets praised for taking longer.

Everything below argues for doing it anyway, because time saved at the front end gets spent three times over on site.

The quality of coordination is decided by the agreements made before anyone opens a model, and no volume of clash detection afterwards recovers what was skipped.

Conflicts Were Just Normal

Rubens started as a civil engineering technician in Brazil in 1988 and went straight from college onto site, where he saw what he now calls clashes. Back then they were conflicts and problems, a normal part of building. The design phase was rushed. That part has followed him for thirty years, through a move to Ireland and onto bigger projects with more resource to do the right thing.

A professor had told him during his masters that the procurement route matters enormously, and he dismissed it. Then he worked on data centres and felt it. Traditional procurement and design and build produce different information flows and moments of commitment, and therefore different volumes of rework. The clashes arrive late. The conditions that created them were set in the contract.

He later proposed a coordination rating on LinkedIn, so a project could answer whether a design is ready for the next phase. The sharpest objection was that you cannot discuss coordination before the level of information need is defined.

That is the argument in one line. Coordination is a consequence of the information you already have.

So if coordination is downstream, where does the clash itself come from?

Zero Clashes in the Real Building

Rubens was sitting in a busy office with no ceiling, services exposed above him, and noticed there were no clashes anywhere in the room. On his laptop was a model of that kind of building, full of them.

Physics does not permit two objects in the same space. Our software does.

One commenter who had worked in BIM since the 80s explained why. Blocking every intersection was too heavy for the software of the day, so the tools let you model anything and sort it out later. That constraint has long gone, and the default behaviour it created stayed.

Here is the part I find most instructive. A feasibility problem was solved years ago and the industry kept the workaround. I also hear coordination argued as a software choice far more often than as a process question, which is the same mistake in different clothes.

Rules, Then Principles

So he started writing the agreements down. On a precast frame the structural engineer confirms there can be no openings in the beams. That is a rule, and services do not route through them, because anything that does will move later at someone’s cost.

He called them coordination rules, and people objected that a rule sounds absolute. He now calls them principles, agrees five to ten per project, and records them as an appendix to the BIM execution plan.

Then he closed the loop into the authoring tool. A web application lets the BIM manager create each principle during the coordination meeting, along with its consequence. An add-in raises it inside Revit as someone models: coordination rule thirteen, you cannot pass through a concrete beam, are you sure you want to proceed. The modeller can log an exception with a reason, because sometimes the pipe has nowhere else to go.

That exception route is what makes it usable. Teams accept a system that lets them proceed deliberately.

Rubens frames the ladder as reactive, preventive and proactive coordination. Most of us live on the first rung, and the prize for climbing is the 30 to 40 percent of rework that comes from agreements nobody followed.

None of that gets funded, though, unless someone senior values it.

Talk About Money

A director once told him plainly that clash movement was of no interest, and asked whether the project was ready.

So they defined rules for high, medium and low priority. A model might return 200 high, 3,000 medium and 5,000 low. You skip the noise and work the 200. With project type, location and cost data, those 200 become a number: the exposure if they reach site.

On a 200 million pound scheme, 100,000 of residual exposure is noise. Twenty percent is a case you can take to the client for more coordination time.

So do the translation yourself. Telling a manager you reduced 20,000 clashes to 200 earns nothing. Telling them you cut exposure from 20 million to 150,000 changes the conversation.

Which brings us back to going slower. Coordination meeting is where a project is cheap to change, and every hour spent there buys several on site. We still issue PDFs that are a digital version of paper, while a few projects in Norway and Sweden have been built with no drawings at all.