Multi-Discipline BIM Clash Detection

A construction project needed architectural, structural and MEP models coordinated and checked for clashes ahead of issue-for-construction.

Each discipline's model had been developed largely independently up to this point, by different consultants working to their own internal coordination assumptions, which meant a first federation pass was likely to surface a large number of clashes at once — some genuinely critical, many trivial.

The project programme allowed limited time for clash resolution before the issue-for-construction deadline, which meant the clash report needed to help the design team prioritise effectively rather than simply presenting every detected clash with equal weight.

Two of the discipline consultants were using different modelling software with somewhat inconsistent Level of Development conventions, which meant part of the coordination challenge was simply establishing a fair, common basis for comparing their models before clash results could be trusted.

The project owner also required a clear, non-technical summary of coordination status suitable for a monthly stakeholder report, in addition to the detailed technical clash reports the design team itself needed to work from.

A late design change to the building's primary services riser location, introduced after the first federation pass had already begun, meant part of the coordination effort had to absorb a genuinely moving target rather than working against a fully locked design.

One of the three discipline consultants was also working from a significantly older software version, which occasionally produced subtle geometry export inconsistencies when their model was brought into the shared federation environment, requiring a specific check before their model's clash results could be trusted at face value.

Discipline models were federated and run through clash detection, with a structured report issued to the design team for resolution before re-checking.

Before trusting the first clash results, we reviewed the LOD consistency between the two consultants on different platforms, confirming both models represented an equivalent level of real detail rather than comparing a highly detailed model against a comparatively schematic one and drawing false conclusions from the mismatch.

The first-pass clash report was substantial, as expected given each model's independent development history, so clashes were triaged into hard clashes that would physically block construction, soft clearance issues that were easily resolved, and duplicate or near-duplicate detections that added noise without adding new information.

Priority was given to hard clashes affecting elements on the project's critical path, agreed with the project's lead consultant, so design resolution effort was directed where the schedule risk was actually highest.

A second clash detection pass was run after the first round of resolutions, confirming the priority clashes had been genuinely resolved rather than just marked as closed without verification.

A short, plain-language summary was prepared alongside the full technical report each month, translating coordination status and remaining risk into terms suitable for the project owner's stakeholder reporting without requiring them to interpret a raw clash list themselves.

When the services riser relocation was introduced, the affected zone of the federated model was re-run through clash detection in isolation rather than waiting for the next scheduled full-model pass, giving the design team faster feedback on the specific area affected by the late change.

The older-software consultant's model was spot-checked against a handful of known reference dimensions after each export, confirming geometry translated correctly into the shared federation environment before their clash results were relied upon alongside the other two disciplines' models.

Clashes were identified and resolved by the design team ahead of construction issue, rather than being discovered on site.

Triaging the large first-pass clash list into genuinely actionable priorities meant the design team's limited remaining programme time was spent on the clashes that actually mattered to the schedule, not on chasing every detected clash equally.

Checking LOD consistency before trusting comparative results avoided the design team wasting time chasing false clashes generated purely by a mismatch in modelling detail between two consultants, rather than a genuine physical conflict.

The plain-language summaries gave the project owner a clear, ongoing sense of coordination progress and remaining risk without needing to interpret technical clash data themselves each month.

Running a targeted re-check on just the affected riser zone, rather than waiting for the next scheduled full-model pass, gave the design team fast feedback on a late change without losing the benefit of the broader coordination schedule already in place for the rest of the model.

Spot-checking the older-software consultant's geometry export after each update caught a minor translation inconsistency early, avoiding a round of false clash results that would otherwise have wasted the design team's time investigating conflicts that didn't actually exist in the real design.