A clash happens when two or more building elements occupy the same space in a 3D model. For example, an HVAC duct passing through a structural beam or a pipe intersecting a column. Since architects, structural engineers, and MEP engineers work on separate models, these conflicts are common. BIM clash detection identifies them early, allowing teams to resolve issues digitally before construction begins, saving time, cost, and rework.

Why Clash Detection Matters So Much

Before BIM became common practice, teams worked mostly with 2D drawings. An architectural drawing, a structural drawing, and an MEP drawing existed as separate sheets. Checking whether they conflicted meant manually overlaying drawings and hoping someone caught the problem — which, honestly, often didn't happen until construction was already underway.

Here's what an unresolved clash actually costs in the real world:

• Rework — concrete already poured, ducts already fabricated, pipes already installed; all of it may need to be redone

• Delay — every clash found on-site typically means stopping work, raising a query, waiting for a design change, and re-approving the fix

• Cost overrun — labour, material waste, and schedule delays all translate directly into money lost

• Safety risk — a poorly resolved clash, like a duct rerouted in a rush, can sometimes create genuine safety or code-compliance issues

Without Clash Detection vs With Clash Detection

BIM-based clash detection catches these problems weeks or months before construction starts, when a fix is just a few clicks in the model instead of a demolition crew on site.

3. How BIM Clash Detection Works: Step-by-Step Workflow

BIM clash detection follows a simple workflow to identify and resolve conflicts before construction begins.

Step 1: Create Individual Models

Architectural, structural, and MEP teams create their own 3D models using BIM software like Autodesk Revit.

Step 2: Combine the Models

All discipline models are merged into a single federated model for coordination.

Step 3: Run Clash Detection

Software such as Navisworks or Solibri scans the combined model and identifies clashes between building elements.

Step 4: Review and Resolve Clashes

The project team reviews each clash and decides the best solution, such as rerouting ducts or adjusting the design.

Step 5: Update and Recheck  

The models are updated, and clash detection is run again until all major conflicts are resolved.

Step 6: Generate the Clash Report

A final clash report is prepared to confirm that coordination issues have been resolved before construction starts.

Workflow: 

Create Models → Combine Models → Detect Clashes → Review → Resolve → Recheck → Final Report

In S2B's BIM Training, students perform this complete workflow using Autodesk Revit and Navisworks on real project models. This practical approach helps students build genuine, industry-ready skills for BIM-related careers, rather than just watching the process explained in theory.

Types of Clashes You'll Encounter

Not every clash is the same kind of problem, and understanding the difference matters for how you approach fixing them.

Software Used for Clash Detection

Students often assume Revit alone can do everything Navisworks does. Here's the honest comparison:

Want to compare the top BIM tools? Read our guide on 10 Best BIM Software for Civil Engineers.

A Real Project Example

Here's a simple real-world example of how BIM clash detection works on a construction project. 

Imagine a mid-rise commercial building. The structural team has designed a beam running along a corridor ceiling at a certain height. Separately, the MEP team has routed a large HVAC duct along the same corridor, at a height that looks fine on their own drawing.

When both models are combined and scanned in Navisworks, the software flags a hard clash: the duct route runs directly into the beam. On a 2D drawing review, this might easily have been missed, since each team's drawing looked correct in isolation.

The coordination team reviews the clash. Moving the beam isn't an option — it's structural. Instead, they look at two solutions: reducing the duct's cross-section and splitting it into two smaller ducts that pass on either side of the beam, or slightly lowering the duct route in that specific section where headroom allows it. The MEP engineer updates the model, the structural model stays untouched, and the combined model is re-scanned. The clash clears.

Common Mistakes Students and Junior Engineers Make

• When learning BIM clash detection, beginners often make mistakes that affect project coordination. Here are the most common ones:

• Treating every clash the same way – Prioritise critical structural and MEP clashes before minor issues.

• Skipping the re-check process – Always run clash detection again after resolving conflicts.

• Ignoring soft clashes – Check required clearances, not just physical overlaps.

• Not grouping similar clashes – Group related clashes to speed up coordination and reporting.

• Poor documentation – Maintain a clash report to track issues, decisions, and resolved conflicts.

Best Practices for Effective Clash Detection

• Run clash checks early and often, not just once near the end of design

• Set clear clearance rules before checking, so soft clashes are caught consistently

• Group and prioritize clashes by severity and location instead of resolving them in random order

• Involve all disciplines in the review, not just the BIM coordinator

• Keep a clash log across the project, tracking what was found, how it was resolved, and who resolved it

Career Opportunities Built Around This Skill

Clash detection sits right at the centre of some of the most in-demand roles in modern construction and design firms.

Employers value candidates who can apply BIM coordination in real projects, not just operate software. Practical clash detection experience improves opportunities for roles such as BIM Coordinator, BIM Modeller, and MEP Coordinator. 

Thinking about a BIM career? S2B School of Engineering's BIM Roles and Responsibilities guide breaks down each of these roles in more depth, and our BIM & Revit Training Programme is built to prepare you for them with real project coordination practice, not just software tutorials.

Industry Applications Beyond Buildings

Clash detection isn't limited to commercial buildings. The same process applies across a wide range of project types:

• Residential high-rises, where MEP density in shared corridors makes coordination especially critical

• Industrial and manufacturing plants, where piping, structural steel, and equipment layouts are tightly packed

• Infrastructure projects like metro stations and airports, where multiple engineering disciplines and contractors work in the same space

Wherever civil, structural, and MEP teams work on the same project, clash detection helps identify conflicts early, improving coordination and reducing costly on-site changes. 

How to Actually Learn This Skill

Reading about clash detection gets you maybe twenty per cent of the way there. The real skill comes from actually working through a federated model, running a clash test, and making the coordination decisions yourself, because the software part is genuinely the easy part. The judgment calls are what take practice.

If you're a student, here's a realistic starting path:

1. Get comfortable modeling in Autodesk Revit first—you can't coordinate models you don't understand how to build

2. Learn how federated models are assembled from multiple discipline models

3. Practice running clash tests in Navisworks on sample or training project files

4. Work through resolving clashes yourself, not just identifying them

5. Study how experienced coordinators prioritize and document their decisions, not just their software clicks

Frequently Asked Questions

1. What is BIM clash detection?

BIM clash detection is the process of identifying conflicts between architectural, structural, and MEP elements in a 3D BIM model before construction begins.

2. Which software is used for BIM clash detection?

Autodesk Navisworks is the most widely used software for BIM clash detection. Solibri and Autodesk Construction Cloud are also popular coordination tools.. 

3. What is the difference between a hard clash and a soft clash?

A hard clash occurs when two building elements physically overlap. A soft clash happens when elements do not overlap but fail to maintain the required clearance.

4. Do I need Revit to learn BIM clash detection?

Yes. Learning Autodesk Revit first helps you understand BIM models and makes clash detection easier to learn and apply.

5. Where is BIM clash detection used?

BIM clash detection is used in residential buildings, commercial projects, hospitals, airports, industrial plants, and infrastructure projects to improve coordination and reduce construction errors.

 Conclusion

Clash detection is one of those skills that sounds technical until you see it in action, and then it makes complete sense. It's really just careful, systematic checking to catch problems before they become expensive mistakes on site. For students building a career in civil engineering, architecture, or BIM, understanding this workflow isn't optional anymore. It's becoming one of the baseline expectations in modern project teams

Ready to Build Your BIM Career?

Join S2B School of Engineering's BIM & Revit Training Program and learn the following:

• Practical Revit projects, modelled from the ground up

• Navisworks clash detection onreal federated models

• BIM coordination workflow, the way industry teams actually run it

• Guidance from experienced, industry-background trainers

• Placement assistance and career counselling to help you take the next step

If you'd like to understand how this course fits where you currently are, book a free career counselling session with our team—no pressure, just a clear conversation about your goals and the right learning path to get there.