Clash Detection: Finding Problems Before the Field Does

Every contractor knows the cost equation of a site clash: discovery in the model costs hours, discovery on site costs days — plus materials, plus schedule, plus reputation. Clash detection is the discipline of moving those discoveries as early as possible.

The workflow that works

Effective clash management is a cycle, not a single report. Models from architecture, structure and MEP are federated on a regular cadence. Automated interference checks run against defined rules — hard clashes, soft clashes, clearance requirements. Results are grouped, filtered for noise, and assigned to responsible parties through a tracked workflow (BCF exchanges keep the loop clean).

Rules before reports

The quality of a clash process lives in its rules. A duct that passes 20 mm from a cable tray may be a non-issue; the same duct through a structural beam is a redesign. Defining tolerances per system pair — and agreeing them with the consultant up front — turns thousands of raw hits into a short list of real decisions.

What it saves

On our coordination packages across KSA and Egypt, the pattern is consistent: the first federation surfaces hundreds of issues; by the third cycle, the model is clean enough to generate reliable shop drawings. Every clash resolved in the model is a change order that never happened.