// Tech

Rapier Physics with Three.js — Rust-Powered Speed

Rapier (dimforge/rapier) is a Rust-based physics engine compiled to WASM — fastest option for Three.js when simulation complexity matters.

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Rapier is a Rust-native 2D and 3D physics engine, compiled to WASM for browser use. It's the fastest physics option for Three.js when simulation is heavy — 200+ active bodies, complex constraints, soft body cloth simulation. Compared to cannon-es: 2-5x faster on dense scenes, smaller bundle in some configurations, better numerical stability. API is more verbose than cannon-es but well-documented. R3F has first-class Rapier integration via @react-three/rapier. I default to cannon-es for simplicity, switch to Rapier when profiling shows physics is the bottleneck. For typical web 3D (portfolios, configurators, marketing), Rapier's extra speed is overkill; for game-like scenes it's the right call.

How I work with it

On a typical project, rapier 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 rapier 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 rapier physics three js setup is overkill — a CSS-driven hero plus static images converts just as well at 1/10 the cost. rapier physics three js earns its keep when the brand needs a memorable visual moment or when 3D actually clarifies the product (configurators, tours, demos).

What you get hands-off

After delivery: source repository on GitHub (private), commented code, a 5-min Loom walkthrough explaining the scene logic, and the asset pipeline documented. First year of hosting and minor revisions is included. After that we agree on a maintenance plan if needed.

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.

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