Merge IFC Files
Combine two IFC models into one federated file, right in your browser: a single IfcProject, both spatial hierarchies preserved, every property intact — verified output, nothing uploaded.
Your file is processed locally in your browser. Nothing is uploaded.
Model 1
Drop an IFC file here
Model 2
Drop an IFC file here
No files at hand?
Need to federate 3 or more models (architecture + structure + MEP) or merge in batch?
Why merge IFC files?
Real projects rarely live in one model. The architect exports one IFC file, the structural engineer another, the MEP consultant a third — and sooner or later somebody needs them as one deliverable: a client who wants a single file to archive, a CDE slot that accepts one coordination model, an analysis tool that only imports one IFC at a time, or a facility manager who should not have to juggle a folder of fragments. Merging — federating, in BIM terms — produces that single file without flattening anything: each source model keeps its own sites, buildings and storeys as sub-structures of one shared project.
Desktop tools can do this, but they are heavyweight, licensed, and mean uploading confidential models to yet another machine. This tool does the same job in the browser: your models are never uploaded, so NDA and tender material stays on your machine.
How it works
- Drop two IFC files. .ifc or .ifczip from any BIM tool. Each model is indexed and validated — you will see its schema, size, entity count, declared units and spatial skeleton (sites · buildings · storeys) before anything is merged.
- Review the compatibility checks. Both files must use the same IFC schema — mixing IFC2x3 with IFC4 is detected and explained, not silently botched. Differing length units trigger a clear warning, because the merge never rescales your geometry.
- Download the verified federated model. One IfcProject, both hierarchies underneath, every GlobalId unchanged — and before the download button appears, the result is re-parsed with the same engine our viewer uses.
What actually happens to your files
An IFC file is a STEP text file where every entity has a numeric express ID (#123)
and refers to others by those IDs. Two independent files both start numbering at #1, so a
merge has to renumber: the second file's IDs are shifted by a fixed offset and
every internal reference is rewritten to match. Express IDs
are file plumbing, not BIM data — your elements are identified by their GlobalIds, and those
are never touched.
A valid IFC file must contain exactly one IfcProject, so the merged file keeps the first model's project and re-attaches the second model's site hierarchy to it. Everything else is deliberately left alone: each model keeps its own owner history, representation contexts, placements and origin. That is the same structure a coordination platform builds when you load discipline models together — which is why the merged file behaves correctly in BIMvision, Revit, Solibri and every other IFC-compliant tool.
What to check before and after merging
Two things decide whether a federated model lands correctly, and both come from how the source files were exported. First, shared coordinates: discipline models should be exported against the same project base point or survey point — the merge preserves whatever placement each file declares, so models that were never coordinated will sit wherever their authors left them. Second, matching units and schema: the tool checks both and tells you before you waste time. After merging, open the result in the viewer and expand the spatial tree — you should see one project with each source model's site underneath, and clicking any element should show the same properties it had in its original file. If your BIM execution plan requires a specific naming convention for the combined deliverable, simply rename the downloaded file; nothing inside it depends on the file name.
Merge, or just view together?
If you only need to look at several models in one scene — clash-checking a duct against a beam, walking a client through the combined design — you do not need to merge at all: our free IFC viewer loads multiple models side by side. Merge when the file itself must be one: archiving a milestone, feeding single-file importers, or delivering one federated IFC as required by your BIM execution plan. After merging, it is worth running the result through the IFC compressor — combined files carry duplicated geometry definitions that compress well — and checking the combined data in the properties explorer.
Frequently asked questions
Is merging IFC files safe? Will model data be lost?
The merge is designed to be lossless. Every element, property set, quantity, material, relationship and GlobalId from both files survives — entities are re-emitted with renumbered STEP express IDs (an internal file detail, not BIM data). The only line that disappears is the duplicate IfcProject: a valid IFC file has exactly one, so the second file's project is dropped and its site hierarchy is re-attached to the surviving project. Before the download appears, the result is re-parsed with the same IFC engine our viewer uses; if that verification fails, you get an error instead of a broken file.
Can I merge an IFC2x3 file with an IFC4 file?
No — and that is deliberate. IFC2x3 and IFC4 are different schemas: entity definitions, property conventions and geometry representations changed between them, so combining them into one file would require converting every entity, which cannot be done losslessly. The tool detects the mismatch and explains it instead of producing a silently broken file. Re-export both models to the same IFC version from your authoring software, or open them side by side in our viewer, which supports multiple models without merging.
What if the files use different units, like metres and millimetres?
The tool reads the declared length unit of each model and warns you when they differ. An IFC file has one unit assignment for the whole file, so the merged model keeps the first file's units — the second model's coordinates are not converted and would open at the wrong scale. When you see the units warning, re-export the models with matching units before merging. Automatic unit conversion is on our roadmap.
Will the models keep their positions? What about different origins?
Yes — coordinates are copied through untouched. Each model keeps its own placement, representation contexts, origin and true north, exactly as in real BIM federation: if the structural model was coordinated to sit next to the architectural one, the merged file shows them in those positions. If the source models were never coordinated to a shared origin, they will appear wherever their authors placed them — that is a property of the source files, not of the merge.
Are my models uploaded to a server?
No. Both files are parsed, merged and verified locally in your browser using WebAssembly, in a background thread so the page stays responsive. Nothing ever leaves your machine, which makes the tool safe for models covered by NDAs or tender confidentiality rules.
How many files can I merge? Is there a size limit?
The free tool merges two IFC files at a time — merging three or more models in one pass is coming with Premium (join the waitlist from the tool). There is no hard size limit: the two models are held in memory together, so the practical ceiling is roughly 300 MB combined on a desktop machine; we show a heads-up for large files, and mobile browsers cap memory much earlier.