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 Outdated schemas are automatically flagged by the validator.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

BIM Best Practices · 2026-05-28 · 7 min

What Is a BIM Health Check? The IFC Health Score Explained

Your project BEP says 'deliver a quality IFC'. Nobody defines what that means until the model gets rejected. An IFC Health Score turns vague quality requirements into a number everyone can track.

What Is a BIM Health Check? The IFC Health Score Explained — IFC Viewer Online article cover

In every project I've been involved in, the phrase 'quality IFC delivery' appears in the BEP. In not one of those projects was it clearly defined. Validation would happen manually, inconsistently, or not at all — until a coordination model produced nonsense and someone started digging.

A Health Score changes that. It's a single 0–100 number calculated automatically against 44 validation rules. It's the same number every time, on every machine, on every version of the model. It belongs in your BEP as a hard deliverable requirement.

How the Score Is Calculated

The score starts at 100. Each validation issue subtracts points using a logarithmic decay — the 1,000th duplicate GUID error takes away far fewer points than the 10th, because model quality degrades non-linearly. A model that's fundamentally broken (missing IfcProject, zero structural elements, circular spatial references) collapses to near zero; a model with a few naming inconsistencies stays above 85.

3× — weight: schema errors
1× — weight: data warnings
44 — rules checked
80+ — target for CDE delivery

A Health Score turns vague quality requirements into a measurable, contractable deliverable criterion.
IFC Viewer Blog

What Each Threshold Means

43/100 — Critical — do not deliver
73/100 — Needs work
87/100 — CDE ready
96/100 — Excellence

Score 0–59: Critical

Structural problems that will break downstream tools. Missing IfcProject, orphan elements dominating the model, circular spatial references. Do not deliver.

Score 60–79: Needs Work

Significant data quality issues. Acceptable for internal review; not acceptable for CDE delivery or coordination sessions with other disciplines.

Score 80–89: Delivery Ready

Minor issues that don't affect structural validity. Suitable for standard CDE delivery and design coordination.

Score 90–100: Excellence

Clean model. Suitable for LOD 300+ deliveries, ISO 19650 submissions, and procurement-stage BIM.

Adding a Health Score Threshold to Your BEP

A BEP clause costs 50 words to write and prevents weeks of coordination delays. Here's a starting point:

IFC deliveries must achieve a minimum Health Score of 80 as validated by [agreed tool] before upload to the CDE. Models below this threshold will be rejected by the Information Manager and returned to the originator for remediation. The validated score must be attached to the transmittal as evidence.

Score vs. Issue Count: The Key Difference

A model with 800 issues can score 81. A model with 12 issues can score 34. The difference is severity. Eight hundred empty name warnings (info level, tiny penalty each) vs twelve missing IfcProject + broken aggregates + circular spatial references (errors, 3× weight each, logarithmic but still severe).

This is intentional. Optimising for issue count creates perverse incentives — you'd disable the naming rules and look clean. Optimising for a score forces you to fix the things that actually matter.

One caveat on contractualising the number: a score is only meaningful alongside the rule set that produced it, so a threshold clause has to name both. The wording that does that — plus the three other clauses worth adding — is in BEP clauses that actually prevent bad IFC deliveries.

What Is a BIM Health Check? The IFC Health Score Explained