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 Outdated schemas are automatically flagged by the validator.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.

How do I validate an IFC file for free?

Three free routes, and they check different things. The buildingSMART Validation Service checks schema conformance (you upload the file). IfcOpenShell's validate module checks it locally from Python. A browser-based health check runs practical delivery rules client-side in about 30 seconds with nothing uploaded. Before a delivery you normally want the practical check; before a contractual conformance claim you want buildingSMART.

Does a schema-valid IFC file mean it is ready to deliver?

No. Schema validity only says the file is correctly packaged according to ISO 10303-21 and the IFC schema. A file with zero schema errors can still have duplicate GlobalIds, elements sitting outside any storey, thousands of unnamed elements and geometry 10 km from the origin — all of which get models rejected at the CDE. Most rejected deliveries are schema-valid.

Can I validate an IFC file without uploading it anywhere?

Yes. A browser validator parses the IFC with WebAssembly on your own machine, so the bytes never reach a server — the 44 quality rules, the Health Score and the IDS engine all run client-side. For NDA-covered or public-sector models that cannot be sent to a third-party service, this is usually the only compliant option.

What Health Score should I reach before sending a model?

80 or above for a normal CDE delivery or design coordination round. 90 or above for LOD 300+ and ISO 19650 milestone submissions. 70 is acceptable for an internal concept-stage review. Below 60 the model has structural problems — fix the export before anyone else opens it.

How long does validating an IFC file take?

A browser health check on a typical 20–200 MB discipline model takes seconds to about a minute, because parsing and checking run in a background thread. The buildingSMART service depends on upload time and queue. An IfcOpenShell run is roughly proportional to file size and is normally used unattended in CI.

What should I check in an IFC file before delivery?

GlobalIds unique and well-formed, every physical element inside a storey, exactly one IfcProject with a complete spatial hierarchy, no orphan elements, coordinates near the world origin, standard property sets present, elements named, and proxies kept to a minimum. Then a Health Score of 80 or above, recorded on the transmittal.

Back to the BIM & IFC blog

Validation · 2026-06-03 · 12 min

How to Validate an IFC File Before You Send It (Free, No Upload)

Your BEP says 'deliver a quality IFC' but never defines how to check it. Here are the three real ways to validate an IFC file — the buildingSMART service, IfcOpenShell, and an in-browser health check — what each one actually catches, and the pre-send checklist that stops models being rejected at the CDE.

How to Validate an IFC File Before You Send It (Free, No Upload) — IFC Viewer Online article cover

Almost everyone exports an IFC and sends it. Almost no one checks it first — not because they don't care, but because 'validate the IFC' is genuinely ambiguous. Validate against what? The schema? The project requirements? Whether it'll open in the coordinator's tool? Those are three different questions with three different tools, and conflating them is why so many models get rejected at the Common Data Environment.

This is the practical map: what 'valid' means, the three ways to check it, what each one will and won't catch, and the checklist to run in the ten minutes before you hit send.

The 60-Second Answer

If you just need the model checked before a deadline, this is the whole workflow:

Export to a local folder — never straight to the CDE.
Open the file in a browser validator: it parses locally, so nothing is uploaded.
Read the Health Score, then sort the issues by severity rather than by count.
Fix the causes in the authoring tool — Revit, ArchiCAD, Tekla — and re-export. Never hand-edit the IFC.
Re-check, confirm a Health Score of 80 or above, then upload and record the score on the transmittal.

The rest of this article is why each step is there, and which tool to reach for when the fast route isn't enough.

What 'Valid' Actually Means

There are two layers, and they're independent. A file can pass one and fail the other.

Schema validity

Does the file conform to the IFC standard (ISO 10303-21 syntax, IFC schema, MVD rules)? A file can be schema-valid and still be useless for coordination.

Practical health

Will it actually work downstream? Stable GUIDs, correct spatial hierarchy, named elements, sensible coordinates, present property sets. This is what gets models rejected — and it's not what schema checkers measure.

There is a third layer above these two: checking the model against your project's own information requirements with buildingSMART IDS. That belongs to the EIR rather than to the file itself, and it has its own guide — see IFC Model Checker: schema, quality and IDS. This article stays on the two layers you have to clear before any delivery.

Option 1: The buildingSMART Validation Service

The official, free, web-based service from buildingSMART International. It judges conformity against the IFC standard: STEP syntax, schema compliance, normative rules, and buildingSMART Data Dictionary alignment. It produces an authoritative pass/fail report — this is the reference for schema correctness.

Best for: certifying that a file conforms to the IFC standard, especially for formal or contractual schema-conformance claims.
What it doesn't do: it isn't a practical 'is this good enough to coordinate' score, and you upload the file to a service — a non-starter for confidential project data you can't send to a third party.

Option 2: IfcOpenShell (for developers)

If you write Python, IfcOpenShell validates from the command line: python -m ifcopenshell.validate model.ifc. It's scriptable, free, runs locally, and integrates into CI pipelines for teams that automate QA.

# Validate an IFC file locally with IfcOpenShell
python -m ifcopenshell.validate path/to/model.ifc

# Pipe the results into your own pre-delivery checks
python validate_and_score.py model.ifc

Best for: developers and BIM-automation teams who want validation inside a script or build pipeline.
What it doesn't do: there's no 3D view and no one-click report — a coordinator who just wants to know if the model is OK won't install Python for it.

Option 3: An In-Browser Health Check (30 Seconds)

Drag the IFC into the viewer. It parses client-side via WebAssembly — nothing is uploaded — runs 44 practical validation rules in a background thread, and returns a single Health Score from 0 to 100 plus a per-issue breakdown you can see against the 3D model. This is the layer the other two don't cover: a fast, private, practical judgment of whether the model is fit to send.

Validate a model live

Open the buildingSMART duplex to see a clean Health Score and report, then drop in your own export to check it before delivery. Your file never leaves your machine.

IFC2x3 · 2.4 MB

Open the interactive IFC viewer

What Each Tool Actually Catches

The three options aren't competing answers to one question — they cover different failures. This is the honest breakdown:

Check	buildingSMART service	IfcOpenShell	Browser health check
STEP / schema conformance	Yes — authoritative	Yes	Basic integrity only
Normative rules and bSDD	Yes	Partial	No
Duplicate or malformed GlobalIds	Partial	Partial	Yes
Spatial hierarchy and orphan elements	No	Partial	Yes
Coordinates far from the origin	No	No	Yes
Missing property sets and names	No	No	Yes
Single deliverability score	No	No	Yes — Health Score 0–100
Issues navigable against the 3D model	No	No	Yes
Runs without uploading the file	No	Yes	Yes
Scriptable in CI	Via API	Yes	No

Coverage as of August 2026. "Partial" means the failure is detectable but not reported as a named, actionable issue.

Which One to Use, When

Use the in-browser health check when…

You want to know if a model is fit to send, right now
The file is confidential and can't be uploaded anywhere
You need a number to put in a transmittal or BEP
You want to see issues against the 3D model, not just a log
You are a coordinator, not a developer

Use buildingSMART / IfcOpenShell when…

You need authoritative schema-conformance certification
You are automating QA inside a CI pipeline (IfcOpenShell)
You write Python and want scriptable checks
A contract requires a formal standard-conformance statement
You need MVD / bSDD compliance specifically

The Practical Pre-Send Checklist

Whatever tool you use, these are the things that actually get models rejected. Each maps to a validation rule with a step-by-step fix guide:

No duplicate or out-of-range GlobalIds.
Every physical element sits inside a storey, not directly under Site or Building.
Exactly one IfcProject at the root, with a complete spatial hierarchy.
No orphan elements and no broken aggregates.
Coordinates are sensible — the model is near the world origin, not kilometres away.
Standard property sets are present; elements are named.
Health Score ≥ 80 before any CDE upload.

When the Score Comes Back Low

A low score is rarely a verdict on the model — it's a pointer at the export settings. Almost every failure traces back to one of five causes, and each is fixed in the authoring tool, not in the IFC:

What the report says	Usual cause	Where to fix it
GlobalIds changed since the last issue	The export regenerates GUIDs instead of persisting them	Authoring tool export settings
Elements outside any storey	Levels not flagged as 'Building Story' on export	Level settings in Revit
Model far from the origin	Exported in survey coordinates instead of shared/project coordinates	Coordinate setup before export
High share of IfcBuildingElementProxy	Families with no IFC class mapping	IFC export mapping table
Property sets missing	Pset export disabled, or parameters never mapped	Export configuration

Each of these has its own walkthrough: Why IFC GUIDs Change on Every Export, Why Your Revit IFC Export Breaks, IFC Coordinates Are Wrong and IFC Properties Missing After Export.

Turning the Check Into a Rule

A check that depends on someone remembering to run it isn't a quality process. Put the threshold in the BEP, and attach the evidence to the delivery:

Delivery stage	Minimum Health Score	Evidence to attach
Internal concept review	70	Score only
Coordination round / CDE upload	80	Score + issue report
ISO 19650 milestone, LOD 300+	90	Score + issue report + resolved-issue log

Once the threshold is agreed, the rest is repetition: export locally, validate, fix the cause, re-export, deliver with the score attached. For the wider picture of what quality means across a whole project, see The Complete Guide to IFC Quality.

How to Validate an IFC File Before You Send It (Free, No Upload)