Navisworks Clash Detection: A Step-by-Step Clash Detective Workflow for Saudi and UAE Projects

Running a clash test in Navisworks is not the hard part. Federating six discipline models with the right coordinates, building selection sets that actually isolate the systems worth testing, setting a tolerance that reflects a Gulf ceiling plenum rather than a software default, and closing every issue with a documented status — that is the workflow that separates a coordinator from someone who clicked “Run Test” once. This guide walks through Navisworks Manage screen by screen, from exporting your first NWC to exporting a signed-off clash report, with the settings that matter on Saudi and UAE projects specifically.

This guide assumes you already know what a hard clash, a soft clash and clash severity are, and why the ceiling plenum on a Gulf tower is the hardest coordination zone you will work in. If you need that grounding first, our guide to BIM clash detection: types, process and the discipline test matrix covers it in depth. What follows here is the part that guide does not: the actual sequence of clicks, panels and settings inside Navisworks Manage that turns that strategy into a working coordination cycle.

Navisworks Manage vs Simulate vs Freedom

Before anything else, confirm you are licensed for the right product. Autodesk sells three tiers of Navisworks, and only one of them runs a clash test.

Clash Detective is the tool that runs automated interference tests, and it exists only in Manage. If your firm’s licences are Simulate or Freedom, every step from here on is unavailable — confirm the licence tier before a coordination cycle is scheduled, not after the first meeting is booked.

Before You Open Navisworks: Exporting and Naming NWC Files

Navisworks does not read Revit files directly during active coordination. It reads NWC (Navisworks Cache) files exported from each discipline model.

• NWC stays live-linked to its source Revit file. Re-export it after a model update and Navisworks picks up the new geometry the next time the file is reloaded. This is the working format for every active coordination cycle.
• NWD is a compressed, self-contained snapshot. It is the right format for a client review, an archived coordination milestone, or a static model sent to a party who does not need to update it — never for the model you are actively testing against.

To export: open the discipline model in Revit, go to Add-Ins tab → External Tools → Navisworks (the exporter ships with Revit; install it separately if it is not listed), choose Entire Project, and save as NWC. Repeat for every discipline — Architecture, Structure, and each MEP sub-discipline your project models separately.

Two prerequisites to confirm before appending anything:

• Shared coordinates are set correctly and consistently across every Revit model. A misaligned origin is the single most common cause of a clash report where every element appears to clash with every element.
• Every discipline model has been exported at a consistent LOD for the test you’re about to run. Our guide to LOD 100–500 covers why LOD 350 — not 300 — is the level clash detection actually needs: it’s the level at which hangers, supports and connections exist, and those are what cause most real conflicts.

Step 1 — Append and Build the Federated Model

Open Navisworks Manage. The scene starts empty.

1. Go to Home tab → Append — not Open. Open replaces whatever is currently in the scene; Append adds to it. Using Open by mistake is a common way to lose a federation that took twenty minutes to build.
2. Select the first discipline NWC (typically Structure) → Open.
3. Click Append again and add the next discipline. Repeat until every relevant discipline is loaded.
4. Orbit the model and check visually that all disciplines sit correctly against each other. If anything looks offset, stop — the fix is in Revit’s shared coordinates, not in Navisworks. Re-export the NWC after correcting it. A misaligned federation wastes a coordination meeting on a problem that has nothing to do with the design.

Step 2 — Build Selection Sets by Discipline

Selection sets are what let you test one system against another instead of everything against everything. Skip this step and a clash test on a real building returns tens of thousands of results, the overwhelming majority of which are irrelevant expected contacts.

In the Sets palette (View → Sets), create a named selection for each discipline or sub-discipline you intend to test: Structure, Architecture, Mechanical, Electrical, Plumbing, Fire Protection. On a project with separate MEP consultants for each service, six to eight sets is standard.

Step 3 — Configure a Test in Clash Detective

Open Clash Detective from the Home tab, or use Ctrl + Shift + C. Click Add Test and rename it immediately with something that will still make sense in a report six weeks from now — “MEP vs Structure — Level 12–18” rather than “Test 3”.

Each test needs five things configured correctly before it produces a usable result:

Step 4 — Run the Test and Read the Results Panel

Click Run Test for a single test, or Run All to execute every configured test in the matrix. Navisworks compares every element in Selection A against every element in Selection B and lists each conflict with its 3D location.

On a first run with no prior coordination, expect hundreds to low thousands of results on a mid-size commercial building. That is not a sign of a badly modelled project — it means coordination has not started yet.

Each result carries a status, and managing that status honestly is what makes the log usable evidence later rather than a list nobody trusts:

Step 5 — Comment, Assign and Export BCF

For every unresolved clash, the Comments field should carry three things: who is responsible, what the conflict is and what was agreed, and a due date. “HVAC duct routes through 400mm structural beam at Level 8, Grid C4 — MEP to reroute above, confirmed with structural engineer 12/09” is a usable record. “Fix this” is not.

Export the results as a BCF (BIM Collaboration Format) file for round-tripping with Revit or Autodesk Construction Cloud. A BCF issue carries the 3D viewpoint, element references, status and comments, so the discipline engineer opens it and lands directly on the problem rather than searching the model for a coordinate.

Step 6 — Export the Report and Re-Test

In Clash Detective, click Report. Choose HTML for a readable document to distribute to consultants without a Navisworks licence, or XML for integration with a project management platform. Select the status filter — typically New, Active and Reviewed — and include viewpoints so each clash carries a screenshot.

A report worth submitting to a BIM Manager on a Gulf project contains: project name and date, model versions referenced, total clashes by status, and individual listings with assignment and comments. This is a contractual deliverable on most BIM-mandated projects in the region, not an optional extra — see our guide to the BIM Execution Plan for where the clash detection cycle and reporting frequency should be defined and recorded.

After each model update, re-run the full matrix. A resolved clash from cycle three can reappear in cycle four if a beam moved or a duct was rerouted for an unrelated reason. Version each NWD snapshot at the close of a cycle with a dated filename so the coordination history stays reconstructable.

Tolerance Settings for Saudi and UAE Projects

Generic tolerance advice — “use 25mm for piping” — is not something you should carry unchanged into a Gulf project. Two things make the region specific, and both belong in the Rules tab and the BEP before the first test runs.

Fire and life safety clearances are reviewed by the authority, not negotiated in the meeting

In both Saudi Arabia and the UAE, fire protection clearances — obstruction rules around sprinkler heads, access to fire equipment, standpipe clearances — are reviewed by Civil Defence and are prescriptive rather than a matter of project preference. In the clash matrix, these belong in the clearance tests classified as critical severity from the outset, not treated as soft coordination items to be traded away when the ceiling plenum runs out of depth.

Local code references, not defaults

Set clearance tolerances from the applicable reference for the jurisdiction — the Saudi Building Code (SBC) for Kingdom projects, and the relevant Dubai Municipality or Abu Dhabi DMT circular, or green-building frameworks such as Al Sa’fat or Estidama where they apply, for UAE projects — rather than a generic figure carried over from a different market’s code. The equipment manufacturer’s stated access dimension should govern maintenance clearance tests; a default number in Navisworks’ clearance field is a starting point for discussion, not a specification.

Why the plenum is tighter here than the software’s defaults assume

A Navisworks tolerance table written for a temperate-climate project understates what a Riyadh, Jeddah or Dubai ceiling void is actually carrying. Cooling load in the region drives larger ducts, larger chilled water mains and more terminal units into the same plenum depth as containment, drainage falls and the sprinkler network — which is exactly why mechanical-versus-structure sits at the top of the discipline priority matrix on almost every Gulf project. If your test matrix and tolerance table were built for a different climate, it is worth rebuilding them rather than adjusting them.

Navisworks Shortcuts Worth Memorising

Six Workflow Mistakes That Waste a Coordination Cycle

Frequently Asked Questions

Conclusion

The Clash Detective interface itself is not complicated — Add Test, set two selections, choose a type and a tolerance, click Run. What separates a coordination cycle that actually converges from one that generates the same argument every week is everything around those clicks: NWC files kept current, selection sets built with intent, tolerances that trace to a code reference instead of a default, statuses that are only closed once they’ve been verified, and a report that reads as evidence rather than a raw export. On a Gulf project, where the ceiling plenum carries more service density than almost anywhere else and Civil Defence clearances are not negotiable, that discipline matters more than it does elsewhere — and it is usually the difference between a model that coordinates on screen and one that installs on site.