Key takeaways
- 01Clash detection finds conflicts between systems (a duct through a beam) in the model, before they become field rework.
- 02There are hard clashes (physical overlap), soft/clearance clashes (insufficient space for install/maintenance), and workflow/4D clashes (scheduling conflicts).
- 03A field clash typically costs an order of magnitude more to fix than a model clash — the ROI of coordination is dramatic.
- 04AI now prioritises and classifies clashes so teams resolve what matters instead of drowning in thousands of false positives.
Clash detection is the most tangible payback of BIM. By federating discipline models and automatically finding where systems occupy the same space, you turn a construction problem — the duct that won’t fit past the beam — into a design problem you solve at a desk. The economics are lopsided in your favour: fixing it in the model is cheap; fixing it in the field is not.
The three kinds of clash
- Hard clash: two elements physically occupy the same space — a pipe passing through a beam. Unambiguous and always actionable.
- Soft/clearance clash: elements don’t overlap but violate required clearance — a valve with no room to operate, or insufficient maintenance access.
- Workflow/4D clash: a scheduling or sequencing conflict — two trades needing the same space at the same time, caught by linking the model to the programme.
Coordination that shows up in the budget
Clash coordination is where BIM stops being a drawing exercise and starts saving money. Spetia Engineering federates the disciplines, runs AI-prioritised clash detection, and drives resolution so the conflicts are gone before the trades arrive — protecting both the budget and the programme.
Frequently asked questions
What is clash detection in BIM?+
Clash detection federates the different discipline models (architectural, structural, MEP) and automatically identifies where elements conflict — for example a duct passing through a structural beam. It lets teams resolve these conflicts in the model during design rather than discovering them as rework during construction.
What are the types of clashes?+
Hard clashes (two elements physically overlapping), soft or clearance clashes (elements too close, violating install or maintenance clearance), and workflow/4D clashes (scheduling conflicts where trades need the same space at the same time, found by linking the model to the construction programme).
How much does clash detection save?+
A great deal, because the cost of fixing a conflict rises sharply the later it’s found. Resolving a clash in the model is a modeling edit; resolving it on site can stop trades, require rework, and delay the schedule. Coordinated projects resolve hundreds of clashes before construction, and each avoided field clash typically saves far more than its share of the coordination cost.
