BIM coordination software has never been more capable. Navisworks, Revit, Solibri, Trimble Connect the tools can detect clashes automatically, generate reports in seconds, and visualize conflicts in 3D with precision that would have been impossible a decade ago.
So why are field clashes still one of the leading causes of construction rework, schedule overruns, and budget overruns on commercial projects?
After 16+ years of BIM coordination work across 500+ projects commercial towers, hospitals, industrial facilities, mixed-use developments we've identified a consistent pattern. The tools rarely fail. The workflow around the tools fails almost every time.
Here's what the data actually shows, and what separates coordination programs that deliver clash-free construction from ones that don't.
The Misconception: Clash Detection = BIM Coordination
This is where most projects go wrong before they even start.
Clash detection is a function inside BIM coordination. It is not BIM coordination itself. Running a Navisworks clash test and generating a report is roughly equivalent to running a spell checker on a document it tells you where problems exist, but it does nothing about fixing them, tracking resolutions, verifying that fixes didn't create new problems, or ensuring that the resolved model actually made it into the shop drawings.
Projects that treat clash detection as the deliverable "we ran clash detection, here's the report consistently produce coordination packages that contain resolved clashes in the model and unresolved conflicts in the field. The gap between those two things is where the rework lives.
Real BIM coordination is:
- Federated model management across all disciplines
- Structured clash detection at defined project milestones
- A tracked resolution workflow with accountability
- Verification that resolutions are incorporated correctly
- Connection between the coordinated model and fabrication documentation
The report is an intermediate output, not the endpoint
What the Data Actually Shows
Across the coordination projects we've run, three patterns appear consistently regardless of project type, size, or software stack:
Pattern 1: 70% of unresolved field clashes trace back to one of three coordination failures
After conducting post-project reviews on coordination programs where field clashes still emerged after a "completed" coordination process, the root causes cluster into three categories almost every time:
Incomplete discipline coverage (38% of cases)
MEP coordination ran without electrical cable trays modeled in 3D. Architectural coordination didn't include furniture and equipment clearances. Structural coordination used preliminary beam sizes that were later revised. In each case, the coordination model was technically complete — for the disciplines that were actually in it. The missing discipline's conflicts showed up on site.
Coordination-to-shop-drawing disconnect (29% of cases)
The coordination model was clash-free. The shop drawings weren't produced from it. Subcontractors produced their shop drawings independently from 2D coordination drawings, manufacturer standard details, or their own internal references without referencing the resolved BIM model. The conflicts that were resolved in the model reappeared in the fabrication documentation.
Late design changes without model updates (33% of cases)
An architectural revision was issued after the coordination model was finalized. The MEP coordination team wasn't notified, or was notified but didn't have time to update before the shop drawing deadline. The revised architectural condition conflicted with the previously coordinated MEP route. Nobody saw it until installation.
**
Pattern 2: The highest-density clash zones are predictable on almost every project**
After running coordination across projects of varying type and scale, the zones that consistently generate the highest clash concentration are:
Program transition zones - where building use changes (commercial podium to residential tower, single-story to multi-story, mechanical floor between typical floors)
Corridor ceiling voids - particularly on healthcare and residential projects where HVAC, plumbing, fire suppression, and electrical all compete for the same 400–600mm of ceiling void depth
Mechanical plant rooms and riser cores - highest equipment and pipe density, smallest available space, least tolerance for error
- Structural transfer levels - where beam depths increase significantly compared to typical floors, invalidating MEP routes designed against standard-depth assumptions
This predictability is useful. On every new coordination project, we run focused initial reviews on these zones first before the systematic floor-by-floor process. Catching high-density conflicts early, while system designs are still flexible enough to reroute without major redesign, is significantly cheaper than catching them at the 75% coordination stage.
Pattern 3: RFI volume in the first four weeks of construction is a reliable lagging indicator of coordination quality
Well-coordinated projects generate RFIs during construction that are predominantly design clarification questions "what finish material goes here?", "confirm the hardware spec for this door." Spatial conflict RFIs "this duct can't be installed where the drawing shows it", "this pipe conflicts with the beam" should be rare if coordination was done properly.
When we audit projects where the construction phase generated high spatial RFI volumes, the coordination model almost always shows one of the three failure patterns above. The RFIs are the construction phase equivalent of a diagnostic they tell you retroactively where the coordination process broke down.
Tracking RFI categories design clarification vs. spatial conflict vs. missing information on active projects gives project managers an early warning signal that the coordination package has gaps before the full impact becomes visible.
What Actually Works: The Coordination Stack That Consistently Delivers
Based on what we've seen across BIM coordination projects of varying scale and complexity, here's the workflow structure that consistently produces construction-phase results:
1. Full Discipline Coverage Before Any Clash Tests Run
No clash test until every discipline is in the federated model including electrical cable trays, equipment clearances, and architectural casework where relevant. A partial coordination model produces false confidence. Better to delay the first clash run by two weeks to ensure complete model coverage than to run tests against an incomplete model and miss entire categories of conflict.
2. Zone-Priority First, Floor-by-Floor Second
Run initial clash tests on the high-density zones first program transitions, corridor ceilings, plant rooms, transfer levels. These zones have the highest conflict density and the least design flexibility. Catching them first gives disciplines maximum time to reroute while designs are still relatively open. Systematic floor-by-floor review follows, but high-risk zones get priority attention.
3. Clash Log With Accountability, Not Just Report Files
Every identified clash gets a log entry with: clash ID, discipline responsible for resolution, location reference, clash type, resolution agreed, resolution deadline, and resolution verification status. This isn't about bureaucracy it's about ensuring that every clash has a named owner and a verified close-out, not just a report entry that gets filed.
The log runs from first clash test to construction start. Any clash that hits the construction documentation release without a verified resolution gets escalated. In practice, a well-maintained clash log makes that escalation rare.
4. Shop Drawings From the Coordinated Model, Not Alongside It
The most impactful single change in coordination workflow: requiring MEP subcontractors to produce shop drawings directly from or in direct reference to the approved coordinated BIM model. This is the connection that closes the coordination-to-fabrication gap that causes 29% of the field clashes in Pattern 1 above.
Implementing this requires clear contractual language and a workflow agreement with subcontractors before coordination starts. It adds a step to the subcontractor's shop drawing production process. It eliminates the most common mechanism by which coordination resolutions fail to reach the field.
5. Change Management Integration
Every design change issued after coordination begins gets triaged against the coordination model before it's issued for construction. Changes that affect coordinated zones trigger a coordination review and model update before the revised drawing is released. Changes that don't affect coordinated zones get flagged as verified and pass through.
This adds process overhead. It's considerably less overhead than resolving the field clashes that result from unreviewed changes reaching the construction phase.
The Software Is Not the Problem
To be direct about this: the BIM coordination tools available today Navisworks for clash detection, Revit for discipline modeling, Trimble Connect or BIM 360 for federated model management are capable of supporting a coordination process that delivers genuinely clash-free construction documentation. The software is not the constraint.
The constraint is almost always organizational: disciplines working in silos, coordination happening too late in the design timeline, no structured resolution tracking, no connection between the coordinated model and fabrication documentation, and no process for managing the design changes that occur after coordination is "complete."
Fix the workflow and the tools work. Leave the workflow unresolved and the best clash detection software in the world produces reports that get filed while the conflicts get built.
A Note on Scale
The patterns above hold across project types and sizes, but the intensity scales with project complexity. On a straightforward tenant improvement with three MEP trades and no structural complexity, partial discipline coverage and an informal resolution process might produce acceptable results. On a 22-floor mixed-use tower with 6 disciplines, a structural transfer level, and 40 subcontractors producing shop drawings simultaneously, the same informal approach produces field clashes that cost multiples of what systematic coordination would have cost.
The coordination investment required scales with project complexity. The cost of not investing in it scales faster.
Top comments (1)
Informative 👍🏻