# IFC Viewer Online
**Open an IFC file and get a Health Score (0 to 100) in 30 seconds. Then put it on a map, measure it, compare it and turn it into a live digital twin.**
A free IFC viewer, validator and digital-twin toolkit that runs entirely in your browser.
No account. No file size limit. Your models never leave your machine.
[**→ Try it live**](https://www.ifcvieweronline.eu/) · [Demos](https://www.ifcvieweronline.eu/msp-global/) · [SDK docs](https://www.ifcvieweronline.eu/sdk/) · [Blog](https://www.ifcvieweronline.eu/blog/)
[](https://www.ifcvieweronline.eu/)
[](LICENSE)
[](CONTRIBUTING.md)
[](mcp/README.md)
[](https://github.com/j03rul4nd/ifc-viewer-online/stargazers)
**Read this in your language**
English · [简体中文](README.zh-CN.md) · [Español](README.es.md) · [Français](README.fr.md) · [Deutsch](README.de.md) · [日本語](README.ja.md) · [Português](README.pt.md) · [Català](README.ca.md) · [Italiano](README.it.md) · [ไทย](README.th.md)
---
[](https://www.ifcvieweronline.eu/)
Health Score and Fix this first → a live city twin → sun and climate → point clouds → Clip Studio. All in your browser. Try it live →
Tailwind · Radix · Zustand"]
QUEUE["Loading queue
jobs · phases · cancel · retry"]
VIEWER["Viewer (Three.js)
federation, map, twins"]
CACHE[("OPFS cache
reloads skip conversion")]
subgraph WORKERS["Web Workers (WebAssembly)"]
PARSE["ifc-parser
IFC → fragments"]
VALID["validator
44 rules + spatial tree"]
FIX["autofix · export
apply fixes and diffs → IFC"]
IDS["ids
IDS 1.0 check"]
MORE["bcf-parser · snapshot · point-cloud
geo-extract · geo-terrain · geo-buildings
basemap-paint · gif-export"]
end
end
FILE["📄 drop .ifc, folders, zip, data"] --> UI
UI --> QUEUE
QUEUE <-->|hit / miss| CACHE
QUEUE --> PARSE
PARSE -->|fragments| QUEUE
QUEUE -->|fragments| VIEWER
UI --> VALID
VALID -->|streamed issues + Health Score| UI
UI --> FIX
FIX -->|corrected .ifc| DL["⬇ download"]
```
- **State:** small [Zustand](https://github.com/pmndrs/zustand) stores in `src/stores/`; geometry never enters a store, only stable IDs do.
- **Worker boundaries:** every worker message is checked at runtime with [Zod](https://zod.dev) schemas (`src/lib/worker-schemas.ts`).
- **Deep dives:** [`ARCHITECTURE.md`](ARCHITECTURE.md) (data flow), [`docs/MODEL_LOADING.md`](docs/MODEL_LOADING.md) (queue, scheduler, cache), [`DECISIONS.md`](DECISIONS.md) (why things are the way they are).
### Tech stack
| Layer | Technology |
|---|---|
| IFC parsing | [web-ifc](https://github.com/ThatOpenCompany/web-ifc) (WebAssembly) |
| 3D rendering | [Three.js](https://threejs.org/) + [@thatopen/components](https://github.com/ThatOpenCompany/engine_components) / fragments |
| Maps | [3d-tiles-renderer](https://github.com/NASA-AMMOS/3DTilesRendererJS), OpenFreeMap vector tiles, OpenStreetMap / Overture data |
| UI | React 18 + Tailwind CSS + Radix UI, Framer Motion + GSAP |
| State | Zustand 5 |
| i18n | i18next (10 languages) |
| Analytics | PostHog EU, cookieless, no PII, opt-out respected |
| Build / tests | Vite 6 + TypeScript (strict) · Vitest |
| Deploy | Vercel (static) · Cloudflare Worker for share links and contact forms (never sees the model) |
---
## Getting started
Requirements: Node.js 20+ and npm.
```bash
git clone https://github.com/j03rul4nd/ifc-viewer-online.git
cd ifc-viewer-online
npm install
npm run dev # → http://localhost:3000
```
The dev server sends `Cross-Origin-Opener-Policy: same-origin` and `Cross-Origin-Embedder-Policy: require-corp`, which multithreaded WASM (`SharedArrayBuffer`) needs.
| Command | What it does |
|---|---|
| `npm run dev` | Dev server on port 3000 (`PORT` to change it) |
| `npm test` | Vitest suite |
| `npx tsc -b` | Type check |
| `npm run build` | SDK + embed pages + type check + production build into `dist/` |
| `npm run build:sdk` | Only the SDK and its docs (`public/sdk/`) |
| `npm run frags` | Pre-compute `.frag` geometry for the demo models |
| `npm run props`, `npm run tower`, … | Rebuild demo assets with Blender 4.5 (`scripts/blender/`) |
> The build bundles Three.js and `@thatopen/*` into worker chunks and needs a lot of memory; the `build` script already raises the Node heap to 6 GB. You can also self-host with the `Dockerfile` / `docker-compose.yml` (nginx). See [`docs/DEPLOYMENT.md`](docs/DEPLOYMENT.md).
---
## Project structure
```
src/
components/ # UI: Viewer, Toolbar, ValidationPanel, IdsPanel, BcfPanel, GeoPanel, ScenePanel, …
# + measure/ compare/ data/ geo/ pointcloud/ solar/ eir/ requirements/ mobile/ blog/ twin-builder/ …
workers/ # ifc-parser · validator · autofix · export · ids · bcf-parser · snapshot · point-cloud · geo-* · basemap-paint · gif-export
stores/ # Zustand stores (model, scene, validation, editor, loading, bcf, ids, geo, measure, …)
hooks/ # useModelSession, useValidationRunner, useIdsRun, useElementFocus, …
lib/ # viewer.ts · loader.ts · validator.ts · diffStore.ts · worker-schemas.ts
loading/ # load queue, scheduler, convert pool, cache, drop plans
ids/ eir/ autofix/ compare/ certify/ cobie/ # checking, fixing, comparing, reporting
measure/ route/ plans/ # measuring, dimensions, takeoff, routes
geo/ pointcloud/ mesh/ video/ solar/ # map, reality capture, analyses
twin/ scene/ scene-doc/ layers/ connections/ # digital twins and scene documents
capture/ director/ cover/ presentation/ tour/ # capture and presentations
sdk/ # IfcViewer embeddable SDK (built to public/sdk/)
i18n/ locales/ # i18next config + JSON per locale
types/ # Zod schemas + TypeScript types (ValidationRules, RULE_COUNT, …)
public/ # static landings, /fix/ and /blog/ pages, demo models, scenes, SDK build
scripts/ # SEO generators, blog i18n, covers, Blender asset builders, SDK docs
cf-worker/ # Cloudflare Worker: share-link SSR and contact forms (never sees the model)
integrations/ # WordPress plugin
test/ # fixtures
```
---
## Documentation map
Start with these:
| Doc | Read it for |
|---|---|
| [`ARCHITECTURE.md`](ARCHITECTURE.md) | How the app is put together and how data flows |
| [`DECISIONS.md`](DECISIONS.md) | Architecture decisions (D-xx) and the rules they set, e.g. frontend-only |
| [`CONTEXT.md`](CONTEXT.md) | Glossary and product context |
| [`IFC_DOMAIN.md`](IFC_DOMAIN.md) | IFC concepts the code relies on |
| [`CONTRIBUTING.md`](CONTRIBUTING.md) | How to send a change |
| [`docs/README.md`](docs/README.md) | **Index of every doc in `docs/`**, grouped by area, with what is a reference and what is a plan or research note |
---
## The 44 validation rules
Rules run in `src/workers/validator.worker.ts`, gated by a `RulesConfig`. The count lives in one place, `RULE_COUNT` in `src/types`, and a test fails if any doc quotes a different number. (This is separate from the buildingSMART **IDS** check, which runs your own `.ids` file.)
Core: 18 rules (names, GUIDs, types, hierarchy)
`RULE_EMPTY_NAME` · `RULE_EMPTY_LONGNAME` · `RULE_DUPLICATE_NAME` · `RULE_NAMING_CONVENTION` · `RULE_MISSING_TYPE` · `RULE_DUPLICATE_GUID` · `RULE_MISSING_PROPERTY_SET` · `RULE_ORPHAN_ELEMENT` · `RULE_WRONG_CONTAINER` · `RULE_BROKEN_AGGREGATE` · `RULE_INVALID_GUID_FORMAT` · `RULE_SPATIAL_HIERARCHY` · `RULE_CIRCULAR_REFERENCE` · `RULE_EMPTY_PROPERTY_VALUE` · `RULE_MISSING_MATERIAL` · `RULE_ELEMENT_IN_BUILDING` · `RULE_INVALID_IFC_VERSION` · `RULE_ELEMENT_CLASH` (off by default)
Spatial & file header: 11 rules (project/site/storey, ISO 19650)
`RULE_MISSING_PROJECT` · `RULE_MISSING_BUILDING` · `RULE_MISSING_STOREY` · `RULE_EMPTY_STOREY` · `RULE_FILE_DESCRIPTION_MISSING` · `RULE_FILE_AUTHOR_MISSING` · `RULE_PROJECT_LONGNAME_MISSING` · `RULE_STOREY_ELEVATION_MISSING` · `RULE_ISO19650_PROJECT_INFO` · `RULE_ISO19650_AUTHOR_INFO` · `RULE_ISO19650_FILENAME`
LOD, classification & MEP: 9 rules
`RULE_MISSING_CLASSIFICATION` · `RULE_LOD_PSET_MISSING` · `RULE_LOD_QUANTITY_MISSING` · `RULE_LOD_MATERIAL_LAYER_MISSING` · `RULE_MEP_SYSTEM_MISSING` · `RULE_CLASH_MEP_STRUCTURAL` · `RULE_PROXY_OVERUSE` · `RULE_COORDINATE_OFFSET` · `RULE_FILE_SIZE_ANOMALY`
Geometry & storey integrity: 6 rules
`RULE_OPENING_WITHOUT_HOST` · `RULE_STOREY_ELEVATION_DUPLICATE` · `RULE_STOREY_ELEVATION_ORDER` · `RULE_UNIT_CONSISTENCY` · `RULE_SPACE_AREA_MISSING` · `RULE_CONNECTED_MEP`
The Health Score is a logarithmic, diminishing-returns number derived from the weighted severity of all issues (errors such as duplicate GUIDs, warnings such as missing property sets, info such as proxy overuse).
---
## Contributing
New validation rules, translations and bug fixes are especially welcome. Read [`CONTRIBUTING.md`](CONTRIBUTING.md) first.
**Add a validation rule** (`src/workers/validator.worker.ts`):
1. Add the rule ID to `ValidationRules` and its metadata in `src/types/index.ts`
2. Implement the `async` rule: it receives the `IfcAPI` instance, `modelId` and a `SpatialIndex` helper and returns `ValidationIssue[]`
3. Wire it into the `runAllRules` dispatch and set `DEFAULT_RULES[RULE_ID]`
4. Add i18n strings to `RULE_TRANSLATIONS`
5. Run `npm test`: `src/lib/rule-count.test.ts` lists every page and README that still quotes the old rule count
**Add a translation:** copy `src/locales/en/` to a new locale folder, translate the values, and register it in `src/i18n/config.ts`.
**Before opening a PR:** `npm test` and `npx tsc -b`.
---
## Open source, free and paid
**The rules we follow**
1. **Everything that is free in the browser today stays free, forever.** Nothing is taken away from anyone.
2. **What costs a server is paid:** storage, server processing, bandwidth, hosted APIs.
3. **New professional productivity tools** (for example batch work across many files) may launch in a paid plan, even when they run in the browser.
4. **The free plan gets nothing that runs on our servers**, so it never depends on an account or a quota.
**Free, open source (MIT, this repo)**
The viewer, the 44-rule validator and Health Score, one-click fixes and fix guides, buildingSMART IDS, EIR profiles, the editor and IFC export, BCF import/export, version compare, measuring and takeoff, sections and floor plans, capture and presentations, the 3D map, point clouds and data layers, solar / flood / slope analyses, digital twins and scene documents, the JS SDK, iframe embedding and the WordPress plugin. All of it runs in your browser, with no account.
**Paid plans (planned, not live yet)**
| Plan | For | What it adds |
|---|---|---|
| **Pro** | One person | Large files processed on the server, cloud projects with versions and "what changed", private links for clients (expiry, password), cloud BCF issues with free guests, verifiable certificates with your logo |
| **Team** | Studios and engineering firms (from 3 editors; reviewers and guests free) | A shared BCF issue manager, automatic validation on every upload that turns failures into assigned issues, a company standard (EIR/IDS profiles, naming), a client portal with your logo, a publishing gate with audit log, monthly reports |
| **Reception** | Contractors, developers, owners and FM teams who *receive* models | Publish your requirements as a link; suppliers check and fix for free in their browser and deliver through it; you get an inbox of what passed, what failed and who delivers well |
| **Developer** | Platforms and CDEs | Hosted validation API, billed by use |
| **Enterprise** | Large contractors and public bodies | Reception across a portfolio, SSO, DPA, SLA and isolated / on-premise deployment |
> **Not everything is in this repo.** The paid plans are built on **private, closed-source code**: the cloud backend and API, accounts and billing, storage, server processing and the team workspace. That code lives in private repositories and is not covered by the MIT license. Some paid screens exist here only as hidden UI behind flags; they do nothing without the private backend. This repo is the full free product, not the whole company.
## License
The code in this repository is [MIT](LICENSE): fork it, self-host it, use it commercially.
---
## Author
[Joel Benitez](https://github.com/j03rul4nd)
If this project saved you time, a ⭐ helps other BIM people find it.
*Built with [@thatopen/components](https://github.com/ThatOpenCompany/engine_components), [web-ifc](https://github.com/ThatOpenCompany/web-ifc) and [Three.js](https://threejs.org/).*