codepawl/crucible

67js is a WebGL2 renderer with addons for terrain, vegetation, characters, liquid, vehicles and media export. A scene is plain data: each part has a geometry, a matrix and a material. An agent builds and changes a scene through an MCP server, looks at PNG previews and renders stills or MP4 video. The goal is to be as capable as Blender and as light as three.js. docs/goal.md defines each part. See the showcase, the documentation, the guide for agents and the changelog. The FAQ answers common questions.

Showcase

Each picture below is a 67js render. The linked ones open live in the browser.

Airport ramp	AI data center	Container port

Bistro cafe corner	Bistro plaza

Install

Let your agent do it. Paste this prompt into Claude Code, Codex, Cursor, Gemini CLI or OpenCode. The agent installs the package, reads the guide and connects the MCP server.

Install 67js from npm as `67js@npm:@codepawlhq/67js` and connect its MCP server with `npx 67js-mcp`. Read
https://67js.codepawl.com/llms.txt first and follow it.

Claude Code plugin. One command adds the MCP server and both skills. The server starts from the published npm package with npx, so nothing is built locally.

/plugin marketplace add codepawl/67.js
/plugin install 67js@67js

By hand

npm install 67js@npm:@codepawlhq/67js

The registry name is @codepawlhq/67js. The command installs it under the alias 67js, so imports stay short. The package is ESM. The tools need Node.js 20.19 or later, and rendering needs a WebGL2 browser.

Quick start

import { Renderer67, box, sphere } from '67js';

// Column-major 4x4 matrix: scale, then move.
const placed = ([x, y, z], [width, height, depth] = [1, 1, 1]) =>
  new Float32Array([width, 0, 0, 0, 0, height, 0, 0, 0, 0, depth, 0, x, y, z, 1]);

const parts = [
  {
    name: 'Floor',
    geometry: box(),
    matrix: placed([0, 0, 0], [8, 0.1, 8]),
    material: { color: [0.4, 0.42, 0.45], metallic: 0, roughness: 0.9, emission: 0 },
  },
  {
    name: 'Ball',
    geometry: sphere(48, 24),
    matrix: placed([0, 1, 0]),
    material: { color: [0.8, 0.3, 0.2], metallic: 0, roughness: 0.35, emission: 0 },
  },
];

const canvas = document.querySelector('canvas');
const renderer = new Renderer67(canvas, parts, { samples: 4, memoryBudgetMiB: 256 });
renderer.render({ eye: [4, 3, 6], target: [0, 1, 0] });

Call renderer.updateParts(parts) to move or recolour parts without a new upload. Call renderer.resize() after the canvas changes size, and renderer.dispose() before you replace the renderer. The guide covers cameras, lights, effects and every material field. To save a PNG from a script, use the render-from-a-script recipe.

For agents

The package includes an MCP server that connects an agent to a persistent browser renderer. The server needs a local Chrome installation.

npx 67js-mcp --backend gpu --memory 192

Use --backend cpu on a machine without a GPU. With bun, bunx 67js-mcp takes the same flags; CI runs the packaged server under bun on every pull request. An agent authors a JSON recipe, sets lights and fog, imports GLB assets and adds motion. It gets PNG previews back, compares up to four views in a review grid and runs render jobs for stills and MP4 video. The server accepts no arbitrary code and no remote asset URLs. The MCP reference lists its tools.

Two skills teach an agent to drive the MCP tools: build-67js-scene for scenes and materials, and render-67js-media for image and video export. For a plain-text guide, give the agent llms.txt.

viz3d uses 67js. It is a skill that turns places, systems and events into 3D apps and films, and it renders its films and stills in 67js. To add it in Claude Code, run /plugin marketplace add codepawl/viz3d, then /plugin install visualize-in-3d@codepawl.

Addons

Each addon is a separate import, so a page loads only what it uses.

Area	Import	Guide
Lighting	67js/addons/hdri	Image-based lighting from .hdr files
Terrain	67js/addons/terrain, 67js/addons/texture-set	Chunked terrain with scanned ground layers
Vegetation	67js/addons/vegetation, 67js/addons/grass, 67js/addons/clutter	Trees, grass and ground clutter with wind and level of detail
Characters	67js/addons/gltf, 67js/addons/retarget, 67js/addons/skeleton-pose	glTF import, clip retargeting and pose layers with IK
Liquid	67js/addons/spume	Baked liquid playback with refraction and spray
Vehicles	67js/addons/vehicle	Wheeled vehicles on a path
Physics	67js/addons/physics	Rapier contacts and joints recorded into a timeline
Live games	67js/addons/runtime	Game loop with fixed or variable steps and pluggable systems
Live games	67js/addons/input	Input: keyboard, mouse, gamepad, touch, device motion, replay and custom sources mapped to named actions and axes
Live games	67js/addons/streaming	Streaming: loader plugins, distance and request loading, a byte budget with LRU eviction and LOD with hysteresis
Live games	67js/addons/netcode	Netcode: server or host authority, pluggable transports, delta snapshots, client prediction with reconciliation and remote interpolation
Live games	67js/addons/physics-runtime	Live physics: a physics world stepped in the game loop, contact and sensor events, ray, shape and overlap queries
Live games	67js/addons/physics-jolt	Jolt engine: a second engine for live physics, with the same events and queries; needs the optional jolt-physics package
Live games	67js/addons/audio	Spatial audio: sounds on nodes, played from contacts, markers and input, with buses and a limiter
Live games	67js/addons/animation-graph	Animation graph: states, 1D and 2D blend spaces, parameter transitions with crossfades and masked layers for any rig
Live games	67js/addons/player	Player: character, vehicle and flight controllers, follow, first-person, top-down, orbit, chase and side-scroller camera rigs with wall pull-in, custom kinds, swappable at runtime
Live games	67js/addons/game-rules	Game rules: a JSON rule document of variables, triggers and actions, played as a runtime system
Live games	67js/addons/game	Game: a scene recipe with a game section played in a page, and the scene_export_web MCP tool that writes it as a static web build
Modeling	67js/addons/mesh, 67js/addons/modeling, 67js/addons/sculpt	Mesh editing, modeling and sculpt brushes
Offline light	67js/addons/path-tracer, 67js/addons/light-bake	Path-traced stills and baked lightmaps
Post passes	67js/addons/user-pass	Your own full-screen GLSL passes: dither, pixel downscale, quantise
Agents	67js/addons/agent-scene, 67js/addons/agent-asset	Scene sessions with revisions and checkpoints

The documentation page lists every guide.

Render images and video

The render command exports a scene to PNG or MP4 through headless Chrome, on the GPU or on the CPU.

npm run render -- --kind image --scene nature --backend gpu --preset high --output artifacts/nature.png

Video export streams one frame at a time, so a film never sits in memory. The render skill lists every preset and flag.

Run the site locally

1. Install Node.js 22.12 or later.
2. Run npm ci.
3. Run npm run dev. Vite prints the local URL.

Performance claims

verification.md has the measured results and their limits. They compare matching scenes on the same hardware. They do not show a general speed advantage over three.js or visual parity with Blender.

Contributing

Read CONTRIBUTING.md before you open a pull request. It covers setup, checks, code style and the release flow. Coding agents start with AGENTS.md, and npm run preflight runs the pull request checks locally. Questions and bug reports: SUPPORT.md.

Credits

• gl-matrix supplies the matrix math.
• The glTF addon has its own parser. The Draco, meshopt and KTX2 decoders are three.js loaders that you pass in.
• The textures and the HDRI on the site are CC0 scans from Poly Haven and ambientCG. See the texture credits.
• The Bistro renders use Amazon Lumberyard Bistro (CC BY 4.0, from the NVIDIA ORCA library) under a CC0 Poly Haven sky.
• The showcase models and their sources are listed in each world's scene.json under public/showcase/.
• The banner wordmark uses Sora (SIL Open Font License).

License

MIT © CodePawl