Is my IFC file uploaded anywhere?

No. Files are parsed entirely in your browser via web-ifc, a WebAssembly build of the open-source IFC parser. Nothing leaves your machine. The app works completely offline once loaded.

Can I use it with confidential models under NDA?

Yes. Because all processing happens in your browser and no data is ever transmitted to any server, you can safely use it with confidential project models under NDA. There is no service agreement to review with your client — no data changes hands.

Can I share the validation results with my team or client?

Yes. After running validation, click Share Report to copy a link that encodes the full Health Score and issue list directly in the URL — no file upload, no server, no account required. You can also export results as JSON, CSV, or a Validation Certificate. The IFC file itself never leaves your browser.

Yes, fully. IFC Viewer Online works on any modern browser — Chrome, Edge, Firefox, and Safari on both Mac and Windows. No plugin, no installation, no operating system restriction.

What happens if my IFC file is very large?

The app handles files up to 2 GB. Performance depends on your device — files under 200 MB load well on most modern hardware. Once parsed, geometry is cached in OPFS so every subsequent load of the same file is instant, even offline.

How does the validation work?

The validator runs 44 built-in rules in a background Web Worker so the UI stays responsive. Rules cover GUID duplicates, spatial hierarchy, orphan elements, naming conventions, missing type assignments, ISO 19650 property sets, LOD completeness, clash detection, proxy overuse, coordinate offset, storey-elevation integrity, unit consistency, and more. You can also run a buildingSMART IDS specification against the model. Every model receives a Health Score from 0 to 100. Results stream in as each rule completes.

Can I fix errors and re-export a corrected IFC?

Yes. All edits (GUID fixes, renames, property value changes) are held as non-destructive diffs with full undo/redo. Clicking Export IFC applies all diffs to the original binary in a Web Worker and downloads the corrected file — no server involved.

What IFC versions are supported?

IFC2x3, IFC4, IFC4x1, and IFC4x3. The viewer uses the open-source web-ifc parser — the same engine used by most modern BIM tools and @thatopen/components. Outdated schemas are automatically flagged by the validator.

What measurement tools are available?

You can measure lengths between any two points, areas of surfaces, volumes of enclosed elements, and individual edge lengths — all directly in the 3D viewport. Measurements persist as labelled annotations and can be exported alongside your model.

Can I load multiple IFC files at once?

Yes. Load as many IFC files as your device memory allows. Each model has independent visibility, transforms, validation, quantity takeoff, and export. Use the Scene panel to manage, reorder, or remove models at any time.

Does it work offline?

Yes, once the page is loaded. The WebAssembly parser and WebGL renderer run entirely in the browser. Parsed geometry is cached in OPFS so repeat loads are instant even without a network connection.

What are the file size limits?

There is no enforced limit — performance depends on your device. Files up to ~200 MB typically load well on modern hardware. The OPFS geometry cache means you only pay the parse cost once per file.

Is it free? Can I use it for commercial projects?

Yes, completely free. The source code is MIT-licensed. You can use the live app or fork the repository for your own projects, including commercial ones.

Back to the BIM & IFC blog

IFC Tips · 2026-03-28 · 6 min

IFC2x3 vs IFC4: Should You Upgrade Your Export Schema?

Most BIM projects still deliver IFC2x3 despite IFC4 being the ISO standard since 2018. Here's what changes with IFC4, when to upgrade, and how to handle the transition without breaking existing tools.

IFC2x3 vs IFC4: Should You Upgrade Your Export Schema? — IFC Viewer Online article cover

IFC4 was published by buildingSMART in 2013 and became ISO 16739-1 in 2018. Yet in 2025, the majority of IFC files exchanged between BIM tools still use the IFC2x3 schema from 2006. Why the slow adoption, and when does the version choice actually matter?

What Changed in IFC4

Geometry: IFC4 introduces tessellated geometry (IfcPolygonalFaceSet). Complex meshes that require 50 MB of B-rep notation in IFC2x3 can be expressed in 8 MB — roughly 6× smaller for detailed architecture.
Materials: Improved IfcMaterialLayerSetUsage makes wall and slab layer definitions more explicit across tools.
Quantities: Explicit area and volume quantities via IfcElementQuantity are first-class in IFC4, not a workaround.
Infrastructure: IfcFacility and built environment extensions prepare IFC for roads, bridges, and tunnels.

Stay on IFC2x3 If...

Your workflow includes any of: Tekla Structures (check your version's IFC4 support level), older Navisworks installations (pre-2020 have incomplete IFC4 geometry support), or contracts that explicitly specify IFC2x3.

Upgrade to IFC4 If...

You're using: Solibri (full IFC4 support since 2019), ArchiCAD 23+ (excellent IFC4 output quality), or any ISO 19650 delivery where the EIR specifies IFC4. Also upgrade if large file sizes are slowing coordination — tessellated geometry typically halves IFC file size.

IFC2x3 vs IFC4: Should You Upgrade Your Export Schema?