We Only Want Clash Detection. What Does Clash-Only Miss?
Helonic is an AI construction drawing analysis platform for general contractors and MEP teams deciding whether to buy AI drawing review for clash detection only. Clash detection is what most teams picture when they hear coordination, so a request often comes in as "we only want clash." Clashes do cost real money in the field. They are also one kind of drawing error among several.
Direct answer. A clash-only pass finds where systems collide and misses errors that have no geometry: spec sections that contradict drawings, code issues, dimensions that do not close, schedules that disagree with plans, and broken detail callouts. Helonic checks clashes and those in the same run on the PDF set.
What does a clash-only pass miss?
| Check | Example | Why clash misses it |
|---|---|---|
| Specs against drawings | Spec 08 71 00 calls for a closer the hardware schedule omits | Specs are text, not geometry |
| Code | Corridor dead end exceeds the allowed length | Nothing collides; the layout is just noncompliant |
| Dimensions | Room dimensions on A-102 do not add up to the overall | A clash check takes dimensions as given |
| Schedules against plans | RTU-3 on the roof plan is missing from the equipment schedule | The schedule is a table on a sheet |
| Detail callouts | Wall section 3/A-401 cut on the plan, sheet shows 1 and 2 only | A callout cannot clash with anything |
Every row above becomes an RFI or a change order without ever showing up as a clash. The definitions of hard, soft, and workflow clashes are in what clash detection is and what it does not catch.
When is clash-only the right buy?
- Another team or tool already covers code, specs, and document checks, and you have proof it does.
- You are a trade contractor who only needs to know where your work collides with others.
- Several disciplines on the job were never modeled, so a model clash run cannot see them.
If none of those apply, scope the purchase to the full set.
Does a 2D clash check overlap with Navisworks?
Partly. Navisworks checks a federated 3D model, which is the better tool when every trade is modeled and current. A 2D check reads the issued sheets, which matters when civil or low voltage was drawn in CAD, or the set changed after the last export. The trade-off is in 2D vs 3D clash detection and AI vs BIM clash detection.
How do you test whether you need more than clash?
Run a full-set review on a project you already built, then sort the kept findings by type. If clashes are most of what your team keeps, a clash tool may do. If specs, schedules, and callouts make up most of the list, a clash-only purchase would have missed them. Set the rule before the run using how to pilot AI drawing review software. Coverage is one of the criteria in what to look for in an AI construction drawing review platform.
How does Helonic cover clash and the rest?
Helonic runs 2D clash detection on the PDF set alongside spec analysis, code compliance, and schedule verification, with every finding boxed on the sheet for a reviewer to keep or dismiss.
Practitioner insight
“We asked for clash and that's what we got. Clean. The change orders on that job were all spec stuff. Hardware, roofing, a light fixture type. None of it was a clash.”
Conversations with MEP coordinators and VDC leads at general contractors on commercial and healthcare projects.
Frequently Asked Questions
What does a clash-only drawing review miss?
When is clash-only review the right purchase?
Does 2D clash detection overlap with Navisworks?
Does Helonic only do clash detection?
Manas Gandhi
Co-founder & CTO, HelonicManas is the co-founder and CTO of Helonic, where he leads engineering and AI research for construction drawing analysis. He works directly with structural, MEP, civil, and fire protection engineers to translate the way they review drawings into AI systems that flag the issues that actually matter in the field. Before Helonic, he built machine learning pipelines for technical document understanding and has spent the last several years interviewing licensed design engineers and discipline leads to ground product decisions in real practice rather than industry assumptions.
- AI for technical document understanding
- Cross-discipline coordination workflows
- Code compliance automation (IBC, NEC, NFPA, IPC, IMC, ASCE)
- Structural and MEP drawing review systems
Last reviewed by Manas Gandhi · November 2026