OpenFEA

Local-first browser CAD and finite element analysis for static, dynamic, modal, and thermal studies.

Import CAD or create an analytic STEP part, assign materials and boundary conditions, mesh and solve in your browser, then inspect and share the results. OpenFEA Core runs locally; no cloud solver or account is required.

Open the app · User guide · Validation · Local development

OpenFEA is an engineering preview. Results are development-oriented analysis outputs, not certified analysis. Review the assumptions, material data, mesh quality, and validation evidence for each study.

What you can do

Area	Capabilities
Studies	Linear static stress, transient structural dynamics, modal analysis, and steady-state thermal conduction.
Geometry	STEP/STP, STL, and OBJ import; analytic parametric STEP parts; bracket, beam, and cantilever samples; face selection, dimensions, orientation, and open sections.
Materials and boundaries	Starter and project-specific materials, additive-manufacturing print settings, structural supports, prescribed temperatures, and thermal loads.
Structural loads	Total face force, pressure, surface traction, volume force, remote force, payload mass, and static equivalent bolt preload. Load cases, static combinations, and envelopes.
Meshing	Browser WebAssembly volume meshing, coarse through ultra presets, multi-body connections, and a static mesh-convergence ladder.
Results	Stress, displacement, safety factor, dynamic playback, natural frequencies and mode shapes, temperature, and heat flux as applicable.
Sharing	Portable .openfea.json projects with geometry and saved results, an offline HTML result viewer, selected-state CSV/VTU, and HTML/PDF reports.

The user guide explains each workflow and its limits, including the initially closed linear contact approximation, equivalent bolt preload, and the guarded 150,000-DOF browser solve ceiling. The WebGPU package supports development benchmarks; automatic large-model GPU routing is currently disabled.

Quick start

Use Node.js 22 and the pnpm version pinned in package.json. From the repository root:

pnpm install --frozen-lockfile
pnpm build:core
pnpm --filter @openfea/web dev

Open localhost:5173, choose Load sample project to try a prepared study, or create a project and import your own geometry. OpenFEA Core packages live in this monorepo under packages/*; no sibling checkout is needed.

The full product runs in the web app; pnpm dev is shorthand for the last command above. See local development.

Local storage and privacy

• Geometry processing, meshing, solving, result inspection, and reports run in the browser. Workspace state uses localStorage and IndexedDB; Save project writes a portable .openfea.json file.
• After the app reports Offline-ready, its service worker has cached the app and analysis assets for offline use.
• If browser autosave runs out of space, OpenFEA asks before uploading a recovery snapshot. It encrypts the snapshot in the browser; the server stores ciphertext without the decryption key. Recovery backups expire after 30 days. Saving a local file remains available.
• Production enables Glimpse aggregate backend statistics. Browser usage analytics require an explicit opt-in under Storage → Optional usage analytics and remain off until granted. Withdrawal stops future collection; DNT/GPC suppress browser sends. Metrics use fixed categories and coarse buckets without model contents, filenames, project names, or visitor identifiers. See Glimpse collection and controls for payload limits and deployment/verification details.

Development and verification

Build Core packages before typechecking consumers because package exports resolve to emitted dist files. The main checks are:

pnpm build:core
pnpm --filter "./packages/*" --if-present test
node scripts/verify-cloudflare-config.mjs
pnpm typecheck
pnpm test
pnpm verify:step-selection-browser
pnpm verify:project-results-browser
pnpm build:cloudflare
pnpm --filter @openfea/web check:bundle

The in-browser mesh and offline PWA proofs (pnpm verify:wasm-mesh-browser, pnpm verify:offline-pwa) need a separate build made with VITE_BROWSER_PROOF=1 pnpm --filter @openfea/web build. This opt-in verification artifact includes the URL-driven mesh harness; normal release builds remove it. CI runs both proofs on their own proof build; verify-100k-solve and pnpm verify:perf stay manual. Threaded Gmsh requires the checked-in COOP/COEP headers on both the app shell and workers; Vite development and preview serve the same isolation headers. Rebuild normally before deploying.

The browser checks require Chrome or Chromium; set CHROME_BIN if auto-detection cannot find it. STEP selection uses ports 5198/9336, project/results checks use 5199/9337, the mesh proofs use 5196/9333 and the offline proof uses 5199/9334. The bundle check must follow the production build. CI delegates to the pinned fleet workflow; it also enforces runner isolation and routing policy.

pnpm build and pnpm build:cloudflare both build Core and the production web app. pnpm verify:perf builds and checks web performance.

Production hosting

The production app is fea.esau.app. A Cloudflare Worker serves static assets, encrypted recovery backups, the analytics relay, and health routes. Simulation jobs stay in the browser. The production build compresses Gmsh WASM before generating the service-worker precache and checking bundle budgets.

For an authorized production deployment:

pnpm deploy:cloudflare

This verifies the configuration, builds the app, and deploys with wrangler.jsonc. For Cloudflare Builds, use:

Build command: pnpm run build
Deploy command: npx wrangler deploy

Non-production branch builds use npx wrangler preview. The checked-in previews block disables analytics and omits production service, R2 and rate-limiter bindings. Browser-local modeling and simulation remain available; encrypted cloud recovery returns unavailable on previews. Preview resource isolation is enforced by verify:cloudflare-config.

pnpm deploy:cloudflare is also a supported deploy command. Do not use npx wrangler versions upload for the production Worker: version uploads cannot apply the retired Durable Object cleanup migration. The separate deploy:cloudflare:static target is non-production and omits the production domain. See local development and cloud retirement for deployment commands and the one-off retired Durable Object cleanup procedure.

Production Uptime

Endpoint	Purpose
GET /health	Release contract: expected Worker/service identities and solverRuntime: "browser-openfea-core". The production-health workflow checks it every 30 minutes.
GET /healthz or HEAD /healthz	Public Worker liveness without storage or upstream requests. Returns HTTP 200, JSON status: "ok" for GET, and Cache-Control: no-store; other methods return 405.

Neither endpoint verifies browser geometry or solver execution. Retired cloud solve routes return HTTP 410. Cloudflare Access, WAF, and bot challenges run before the Worker; monitoring exceptions must be scoped to the intended hostname and exact GET/HEAD /healthz route and verified from the monitor's network.

Repository layout

Path	Role
apps/openfea-web	Production React/Vite workspace and Cloudflare Worker.
packages/*	OpenFEA Core model, examples, CPU solver, WebGPU solver, and viewer.
libs/*	Schema, units, materials, samples, CAD/STEP and mesh intake, study validation, solve pipeline, and Core adapter.
examples/*, docs/*	Sample fixtures, user documentation, architecture, and validation evidence.

CAD topology references remain the source of truth for supports, loads, connections, and named selections. Meshes are generated artifacts; results and reports belong to their study run. Computed FEA, preview estimates, benchmarks, and historical cloud results retain distinct provenance. See architecture.

Compatibility

New project downloads use .openfea.json and the openfea-local-project envelope. Existing .opencae / .opencae.json projects and browser autosaves remain readable. Packages and workspace paths use @openfea/* and openfea-*.

Some storage keys, Core schema/provenance identifiers, backup headers, the opencae-project-backups bucket, and archived fixtures retain their original identifiers for compatibility. Renaming infrastructure requires a separate migration.

Documentation

• User guide
• Architecture
• Local development
• Project file format
• Validation
• Analytics and privacy
• Cloud retirement

License

OpenFEA source code is licensed under Apache-2.0. Separately licensed third-party components, including OCCT/occt-import-js, retain their own licenses; see NOTICE and THIRD_PARTY_NOTICES.md.

Copyright 2026 Esau Engineering. The OpenFEA name and logo are trademarks of Esau Engineering.