Fix Duplicate GUIDs
in IFC Files
Detect every duplicate and malformed GlobalId in your IFC file and fix them all with a single click — entirely in your browser. No upload, no install, no account. Works with exports from Revit, ArchiCAD, Tekla, and more.
How it works
4 steps to a clean IFC file
The entire process runs in your browser — the IFC file never leaves your machine.
Root causes
Why duplicate GUIDs occur
Duplicate GlobalIds are one of the most common IFC quality issues — and most BIM Coordinators only discover them during coordination review or model delivery.
| Authoring Tool | Common cause | When it occurs |
|---|---|---|
| Revit | Copy/Monitor across linked models | When elements are monitored across host and linked files and re-exported separately |
| Revit | Duplicate Types command | Duplicated families re-use the source element's GlobalId |
| ArchiCAD | Hotlink modules | All instances of a hotlinked module share the source element GUIDs |
| ArchiCAD | Copy-paste between projects | Elements copied between ArchiCAD files retain their original GUIDs |
| Tekla | Model splitting / merging | Sub-models merged after being split from a common model retain matching GUIDs |
| Any tool | Model merge without GUID regen | Federating multiple discipline models without checking GUID uniqueness across all files |
The fix
What the auto-fix does (and doesn't do)
Understanding exactly what changes when you fix duplicate GUIDs.
What changes
- ✓Each duplicate element gets a new, unique RFC 4122 GUID
- ✓Invalid base64 GlobalIds are regenerated to spec
- ✓Exported IFC passes GUID uniqueness checks in downstream tools
What stays the same
- —All element names, properties, geometry unchanged
- —Relationships and containment structure unchanged
- —Non-duplicate GUIDs unchanged
Note: If your coordination workflow relies on persistent element identifiers (e.g., BCF issue tracking by GlobalId), fixing duplicates will change some element identities. This is unavoidable — duplicate GUIDs cannot be left as-is in a correctly formed IFC file.
Free tool · in your browser
IFC GlobalId toolkit
Validate GlobalIds, spot duplicates across a list, and generate fresh spec-compliant ones — all client-side, nothing uploaded. These are the same checks (RULE_INVALID_GUID_FORMAT, RULE_DUPLICATE_GUID) the validator runs on a whole model.
This works on GlobalIds you paste here. To scan an entire model for duplicates and auto-fix them in one click, open your IFC in the viewer and run validation — the file never leaves your machine either.
FAQ
Questions about IFC duplicate GUIDs
Why does my IFC file have duplicate GUIDs?
Duplicate GlobalIds are one of the most common IFC export errors. They occur when BIM authoring tools copy elements without generating new unique identifiers, when models are merged without GUID deduplication, or when export plugins incorrectly reuse existing GUIDs. Revit (Copy/Monitor), ArchiCAD (Hotlink modules), and Tekla (model merging) are the most common sources.
What problems do duplicate GUIDs cause?
Duplicate GUIDs break element identity across federated models. Clash detection tools, BCF issue trackers, COBie exports, and IDS validation all rely on GlobalId uniqueness. Some viewers fail silently on duplicates; others show incorrect property data for affected elements. Any automated data exchange workflow that uses GlobalId as a stable key will produce incorrect results when duplicates are present.
Is the IFC file uploaded to fix the GUIDs?
No. The entire process runs in your browser via web-ifc WebAssembly — parsing, validation, fix generation, and export. The IFC file never leaves your machine. This makes it suitable for confidential project models under NDA.
Can I fix just some GUIDs instead of all duplicates?
Yes. The validation panel shows each duplicate individually. You can apply the fix per-element from the issue row, or use Fix All to resolve all detected duplicates at once. All fixes are non-destructive (diff-based) with full undo/redo until you export.
How does the validator detect duplicate GUIDs?
The RULE_DUPLICATE_GUID check indexes all IfcGloballyUniqueId values across all entities in the STEP file and flags any GlobalId that appears more than once. RULE_INVALID_GUID_FORMAT additionally checks that each GlobalId conforms to the IFC base64-encoded 22-character format defined in ISO 16739.
Does this work with all IFC versions?
Yes. The tool supports IFC2x3, IFC4, IFC4x1, and IFC4x3. The GlobalId validation and fix mechanism is identical across all IFC schema versions.
Fix your duplicate GUIDs now.
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