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 Outdated schemas are automatically flagged by the validator.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 · 2026-05-10 · 9 min

IFC, RVT, NWD, DWG: Which BIM File Format Should You Deliver?

Your structural engineer delivers RVT. Your MEP contractor uses NWD. The client wants IFC. Your PM is asking for DWG drawings. Here's how to navigate the format maze and why open BIM actually matters for delivery.

IFC, RVT, NWD, DWG: Which BIM File Format Should You Deliver? — IFC Viewer Online article cover

BIM projects produce models in a dozen formats. Most of them are proprietary. Most of them require the same £5,000 software license to open. When the client needs to inspect the model, run a quantity takeoff, or hand it to a facilities manager for the next 30 years, none of those licenses will be there.

That's the practical argument for IFC. Not ideology — logistics.

The Four Formats You'll Actually Encounter

IFC (.ifc)

ISO 16739-1. Open, vendor-neutral, schema-driven. Every certified BIM tool can export it. The only format your client can still open in 2045.

RVT (.rvt)

Autodesk Revit native. Rich parametric data and family libraries. Requires Revit to open — and the correct Revit version. Not forward-compatible.

NWD / NWF (.nwd)

Navisworks. A coordination-only format: aggregates geometry from multiple sources for clash detection and timeliner. Read-only; no way to push changes back.

DWG (.dwg)

AutoCAD / Autodesk. 2D drawings and some 3D geometry. Not a BIM format — no semantic data, no spatial hierarchy, no property sets.

IFC — Open BIM

Readable by any certified BIM tool
Permanent asset — no vendor dependency
Includes full property sets and spatial hierarchy
Supports BCF coordination workflows
Can be validated against schema rules
ISO 16739-1 internationally standardised
Required for ISO 19650 compliance deliveries

RVT / NWD — Proprietary

Requires vendor software to open
Format changes break backwards compatibility
Richer parametric data in the native tool
Faster for internal design workflow
NWD clash detection is more precise than IFC clash
No universally agreed schema for validation
Difficult to deliver to FM without a licence

When to Use Each Format

Use IFC for:

All formal CDE deliveries and information exchanges between organisations.
Handover packages to clients, facilities managers, and asset owners.
Any delivery governed by ISO 19650 or a project EIR.
Cross-discipline coordination where participants use different authoring tools.
Long-term archival — an IFC file from 2004 still opens in a 2026 validator.

Use RVT for:

Internal design work within an all-Revit team.
Sharing design intent with consultants who also use Revit and the same version.
Parametric design exploration where IFC round-tripping would destroy family relationships.

IFC Schema Versions: Which to Choose

IFC4 (ISO 16739-1:2018): Current standard. Better geometry compression via tessellation (50-70% smaller files), improved material layer assignments, explicit quantity sets. Use this for all new projects.
IFC2x3: The legacy standard from 2006. Still widely supported and required by some contracts and CDEs. Choose if your EIR specifies it, or if any receiving tool doesn't support IFC4.
IFC4x3: The new infrastructure extension for roads, bridges, tunnels. Only relevant for civil/infrastructure projects. Limited tool support as of 2026.

Why Most Projects Still Deliver IFC2x3

Inertia. IFC2x3 was the standard for 15 years; every tool supports it. IFC4 has been available since 2013 and ISO-ratified since 2018, but many CDEs, viewer tools, and procurement workflows were built around IFC2x3 assumptions. Until your CDE explicitly validates IFC4, check before you upgrade.

IFC4 Sample House

A real IFC4 residential model with full property sets, correct spatial hierarchy, and IFC4-native geometry. Open it to see how IFC4 validation compares to IFC2x3 — and what a 90+ Health Score looks like.