What is clash detection in BIM and why is it important?
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Clash detection is the process of identifying geometric conflicts between building disciplines — like a duct passing through a structural beam or a pipe conflicting with a ceiling grid — inside a federated 3D model, before construction begins. Clash detection services typically catch hundreds or thousands of conflicts that would otherwise surface as RFIs, change orders, and field rework. Catching them in the model costs almost nothing; catching them on site costs weeks and serious money.
What is the difference between hard clashes and soft clashes?
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A hard clash is a physical overlap — two objects occupying the same space, like a beam cutting through a duct. A soft clash is a clearance violation — objects that don't physically touch but violate required separations, such as a pipe within 6 inches of an electrical panel where code requires 36 inches of clearance. Comprehensive clash detection services test for both: hard clashes catch geometric conflicts, soft clashes catch maintenance access, code compliance, and operational issues.
Which software is best for BIM clash detection?
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Autodesk Navisworks Manage is the industry-standard tool for BIM clash detection — federating models from Revit, AutoCAD, Tekla, and other platforms, then running automated clash tests with Clash Detective. Revizto and Solibri Office are also widely used for issue tracking and BCF exchange. Our clash detection services use Navisworks for testing and Revizto or BIM 360 / ACC for issue management — matched to whatever your team already runs.
How many clashes are normal on a typical project?
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First-run clash detection on a moderately complex commercial building can flag 500–2,000 clashes — and on a healthcare or lab project, that number can run into the thousands. This is not a sign that something is wrong; it means coordination hasn't started yet. Well-managed clash detection services typically resolve 80–90% of clashes within the first 2–3 coordination cycles, with the remainder narrowed to genuine constructability decisions rather than oversights.
How do you prioritize and group clashes in a Navisworks report?
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Raw Navisworks output is overwhelming — running everything against everything produces thousands of low-value results. Effective clash detection services apply a clash matrix (rules defining which disciplines test against which) and group clashes by location, type, and trade ownership. Each clash is categorized as critical (must-fix), important (should-fix), or minor (review), and assigned to the responsible trade with a 3D snapshot and resolution note. This converts a clash report from raw data into an actionable issue log.
Who is responsible for resolving the clashes once they are detected?
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Clash detection services identify and document conflicts; resolution is owned by the responsible trade based on the BIM Execution Plan. Typically MEP reroutes around fixed structural elements, structural avoids fixed architectural openings, and architectural adjusts when ceiling zones need more clearance. The clash detection team facilitates — assigning issues, tracking status, and re-testing after fixes — but the design decision belongs to the discipline making the change.
How long does clash detection take on a typical commercial project?
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Clash detection itself is fast — running a Navisworks clash test takes minutes. The value-creating work is in setup (clash matrix, selection sets, rules), review (filtering false positives, grouping issues), and the coordination cycles that follow. For a typical commercial project, the first comprehensive clash detection cycle takes 5–10 business days from federated model receipt to delivered clash report; subsequent weekly cycles run 2–3 business days each as issues are progressively cleared.
What deliverables do you provide with clash detection services?
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Every clash detection cycle includes a Navisworks federated file (.nwd), a structured clash report (PDF or Excel) with categorized issues and 3D snapshots, a BCF or NWD issue export for stakeholder review, an action log assigning issues to trades, and a revision-tracked update from the previous cycle. We also provide coordination meeting minutes and post-meeting issue updates so the project record is fully auditable.