// Tech

Ammo.js Physics in Three.js — Bullet Physics for Web

Ammo.js is the WASM port of Bullet Physics — full-featured rigid body simulation for Three.js scenes that need it.

Ammo.js is a WebAssembly port of Bullet Physics, the engine used in Blender and many AAA games. It brings full rigid-body simulation, soft bodies (cloth, rope), and constraints to Three.js. Compared to alternatives: cannon-es is JS-native and lighter (~50KB vs Ammo's ~700KB), simpler API, sufficient for most web projects. Ammo.js is heavier but more accurate — vehicle simulations, complex constraint systems, soft body cloth. I default to cannon-es for medium complexity, switch to rapier (Rust-WASM, fastest) for production-grade simulations. Ammo.js sits in between — use it when migrating from Blender/Bullet asset pipelines or when accuracy matters more than bundle size.

What this delivers

Concrete output: a working ammo physics three js integration on a real production site, not a demo. The integration includes device-tier detection so weak phones get a lighter version automatically. Source files are handed over in their original formats — Blender, GLSL, glTF — so any future developer can continue where I stopped.

How I work with it

On a typical project, ammo physics three js ships as a self-contained module: one entry-point JS file, one CSS file, asset bundle below 1.5MB total. I keep the integration sandboxed so the rest of the site stays SEO-friendly classical HTML. Frame budget targets 60 FPS on a mid-range Android, with a measurable fallback below.

Performance budget

Lighthouse mobile target: 85+ across all categories. I measure on real devices, not just emulator. Asset compression: glTF + Draco for meshes, KTX2 for textures, Brotli for shaders. Lazy-load any ammo physics three js scene that isn't above the fold so the first paint stays under 1.5s.

When this is overkill

If the goal is a simple e-commerce listing or content blog, a full ammo physics three js setup is overkill — a CSS-driven hero plus static images converts just as well at 1/10 the cost. ammo physics three js earns its keep when the brand needs a memorable visual moment or when 3D actually clarifies the product (configurators, tours, demos).

Frequently asked questions

Why pick this technology over alternatives?

It has the largest production-quality ecosystem, the most documentation, and the most experienced developers available. For a site you want to maintain for 3+ years, ecosystem maturity matters more than feature peak.

What if a newer tool comes out next year?

I track new tooling and migrate when it makes sense, but only after the new tool ships stable production releases for at least 6-9 months. I don't rebuild client sites on bleeding-edge tools — that's the path to broken sites.

How long does this take?

Standard scope: 4-6 weeks from contract signature to live site. Larger scope (configurator, multi-scene scrollytelling) takes 8-12 weeks. Rush projects (2-3 weeks) are accepted with a 30-40% rush surcharge.

What does it cost?

Hero-section 3D upgrade: \$1,500-\$2,500. Full multi-scene 3D site: \$3,500-\$8,000. Configurator with custom shaders: \$5,000-\$12,000. All fixed-price, source code included. EUR equivalents on request.

What if my visitors are on weak phones?

The site detects device tier before the first scene loads and serves a lighter version on weak hardware (fewer particles, simpler shaders). Devices without WebGL get a static fallback that preserves the visual language and conversion path.

Ready to ship a 3D experience?

Tell me what you need — fixed price, fixed deadline, no surprises.

Get a quote +381 61 224 8989