Navisworks Clash Detection Workflow
Clash detection finds the places where building elements occupy the same space. The skill is in setting up the tests so the results are useful and in closing them out.
The workflow
- Federate: combine the discipline models in a shared coordinate system.
- Define tests: choose which sets clash against which (for example electrical containment against ducts and pipes), with tolerances.
- Run and review: inspect results, remove false positives and group related clashes.
- Assign: give each issue an owner and a due date at the coordination meeting.
- Resolve and re-run: update models and repeat until the agreed clash count is closed.
- Report: keep a record for the project team.
Hard and clearance clashes
| Type | Example |
|---|---|
| Hard clash | A cable tray passing through a duct |
| Clearance clash | A switchboard without the required front access space |
Practical tips
- Agree coordination zones and priorities before modelling, so fixes follow rules, not arguments.
- Model clearance zones in the families so clearance clashes are caught.
- Close clashes in priority order, with the largest systems fixed first.
Related: cable tray modeling and BIM coordination process.
Written by the Vision Matrix Institute editorial team. Worked examples use stated, illustrative assumptions; check them against your project data, the applicable standards and manufacturer datasheets before use.
Frequently Asked Questions
What is a clash?
Two elements that occupy the same space (a hard clash) or violate a required clearance (a clearance or soft clash).
What does Navisworks do?
It combines models from different disciplines into one federated model and runs clash tests between selected sets of elements.
Who fixes a clash?
The coordination meeting assigns each clash to the discipline responsible for the change, based on agreed priorities.
Why are there so many clashes at first?
Because early models are uncoordinated and tolerances are loose. Good test setup, grouping and agreed rules reduce noise.
Want to learn this properly?
This topic is covered in depth in our Electrical Design – Data Center Specialist program.
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