Clash Detection is one of the fastest ways to reduce rework, RFIs, and schedule slips on MEP-heavy projects. But it only works when the workflow is consistent: clean inputs, clear rules, disciplined coordination, and documented closeout. If your team treats clashes like “software output,” you’ll get busy reports—but the field will still suffer. Treat it like a construction process, and clash coordination becomes a real production advantage.
What Clash Detection Really Means
Clash Detection is the process of using coordinated 3D models to find conflicts—duct vs. beam, pipe vs. cable tray, conduit vs. drywall framing, equipment clearances—before fabrication and installation. It’s not just “run clashes.” Real clash coordination includes defining what counts as a clash, assigning responsibility, setting deadlines, and verifying closure with updated models.
Why Clash Coordination Matters on Projects
On design-build and fast-track delivery, coordination mistakes move straight into prefab sleeves, and install sequencing. A solid Clash Detection workflow helps teams cut field fixes, protect schedule, and improve prefab accuracy—especially in tight ceiling zones, shafts, corridors, and equipment rooms.
Step-by-Step Clash Detection Process
Step 1: Define Coordination Goals and BIM Uses
Start by aligning on why you’re coordinating. Some projects focus on installability and ceiling-zone routing; others prioritize prefab spools, sleeve layouts, and equipment access/maintenance. This goal-setting step prevents late arguments like “that wasn’t in my scope” when a clash shows up.
Step 2: Lock Model Standards and LOD Expectations
Most coordination failures don’t come from the software—they come from inconsistent modeling. Agree early on LOD expectations (often LOD 300/350 for coordination), what must be modeled (major mains, risers, equipment, shafts), and what “counts” for spacing (insulation, access clearances, required service zones). This is where many challenges in BIM clash detection begin: mismatched detail level, missing scope, and sloppy standards.
Step 3: Establish a Single Coordinate System and Shared Setup
If models don’t align perfectly, every clash report becomes unreliable. Confirm the coordinate strategy, level datums, and how files are linked. Then enforce it—every submission cycle. A quick alignment validation view saves hours later.
Step 4: Create a Model Exchange Routine
Clash Detection needs stable inputs. Set a submission day/time, define file formats, and standardize naming/versioning so everyone is reviewing the same model set. Without a routine, coordination becomes reactive and meeting-driven instead of process-driven.
Step 5: Prepare Models for Coordination (Clean Before You Clash)
Before running clashes, do basic model QC: remove old links, verify system classifications, confirm equipment sizes, and make sure critical routing is actually modeled. A “clean” clash report is meaningless if key systems are missing or simplified.
Step 6: Run the Revit and Navisworks Coordination Process
Most teams rely on a federated workflow: each discipline maintains its authoring model, exports with consistent settings, and then all models get combined for testing and review. The Revit and Navisworks coordination process usually follows this pattern: export consistent NWCs, append into a shared federated model, create search sets by system, and run clash tests that match your coordination goals—not just a giant all-vs-all dump.
Step 7: Set Clash Rules, Tolerances, and Priorities
Not every intersection is a real issue. Define hard clashes (physical overlap) versus soft clashes (clearances/access/service zones). Then set tolerances that match the phase and install reality—too tight creates noise, too loose hides real problems. Finally, prioritize clashes by impact: shafts, corridors, dense ceiling zones, and prefab areas should always be at the top.
Step 8: Review Results and Filter Noise
This is where strong BIM managers save the team. Instead of forwarding hundreds of raw clashes, filter duplicates, ignore irrelevant intersections, and group issues by location and system so trade partners can act fast. Clean viewpoints + clear naming beat long spreadsheets every time.
Step 9: Assign Ownership and Track Issues
A clash without an owner is just a screenshot. Each issue needs a responsible trade, a required action (reroute/resize/offset/add clearance), and a due date. Tracking can live in your CDE/issue platform or a structured log—but the rule stays the same: every clash must have accountability and a path to closure.
Step 10: Deep Focus on Plumbing Coordination in Clash Detection
Plumbing is a common source of “can’t-move-it” conflicts because slopes, cleanouts, vents, and equipment connections limit flexibility. That’s why plumbing coordination in clash detection deserves its own attention, especially in corridors, restrooms, kitchens/labs, and equipment rooms. Also watch sleeve/penetration coordination—late sleeve changes are expensive and disruptive.
Step 11: Validate Fixes and Close Clashes Properly
Don’t accept “we fixed it” verbally. The closeout cycle should be simple: update model → re-export → rerun test → verify visually → mark resolved. If you skip verification, the same clash returns next week with a new ID—and the team loses trust in coordination.
Step 12: Freeze Coordination Zones for Fabrication and Field
When a zone is truly coordinated (for example, a level corridor), lock routing intent and release it for prefab and install planning. This is where Clash Detection creates real value: fewer field improvisations, smoother sequencing, and more reliable fabrication outputs.
The Most Common Challenges That Break Clash Detection
Here are the biggest challenges in BIM clash detection that show up on real projects (and what they usually mean in practice):
- Wrong or shifting coordinates (models don’t truly align)
- Inconsistent LOD (some trades are schematic while others are detailed)
- Missing scope (supports, insulation, sleeves, clearance zones)
- No ownership tracking (clashes discussed but never closed)
- Too much noise (bad tolerances and no filtering discipline)
Quick Checklist
Keep this short list as your minimum standard:
- Coordinates verified and stable
- Model exchange schedule enforced
- Standard clash rules + tolerances applied
- Clashes filtered, grouped, and assigned
- Fixes verified in updated models
Final Takeaway
Clash Detection works best when you run it like a construction workflow: controlled inputs, clear rules, accountable ownership, and verified closeout. Do that consistently, and clash coordination stops being a weekly fire drill—and starts protecting your schedule, prefab, and field execution.
