Clayform

A 3D workshop built for AI agents. Agents model, sculpt, rig, animate and bake effects by editing a semantic scene document. Clayform meshes it, renders it for them to look at, measures what a picture can't show, and exports game-ready glTF. No Blender, no GPU, no browser: it is a Node library with an MCP server.

Docs: clayform.sadelabs.site · Made with it: the showcase

Every image in this README is a real Clayform render, regenerated by scripts/.

Why

Connecting a language model to a traditional 3D package works, but the model is working blind with a low-level API. It writes vertex and coordinate code, has trouble seeing what it made, and can't tell a floating ear from an attached one. Clayform changes the medium instead:

Related MCP server: modelgen

Quick start

Requires Node 20+. Install from npm:

claude mcp add clayform -- npx -y @s1444/clayform mcp

For any other MCP client, the command is npx -y @s1444/clayform mcp. You can also run directly from GitHub: npx -y github:sezginkipel/clayform mcp. To host it for several agents, clayform serve speaks MCP over HTTP with a sandboxed workspace per session (hosting). Scenes are saved in ./.clayform/ (change it with --workspace <dir> or the CLAYFORM_WORKSPACE environment variable).

To install a fixed version, use the prebuilt tarball from Releases: npm install https://github.com/sezginkipel/clayform/releases/download/v0.1.0/clayform-0.1.0.tgz. To work on the code: git clone, then npm install and npm test. Then ask your agent for something: "Make a goblin from the biped template, green skin, pointy ears, and export it with a walk cycle."

What an agent does

// new_scene { "name": "Goblin", "template": "biped" }
// edit — one atomic batch:
[
  { "op": "set_palette", "set": { "skin": "#7fb04a", "shirt": "#6b4a2b", "pants": "#3d3322" } },
  { "op": "update_part", "id": "hair", "set": { "hidden": true } },
  { "op": "add_part", "part": {
      "id": "ear", "role": "ear", "shape": { "type": "cone", "height": 0.16, "radius": 0.045 },
      "attach": { "to": "head", "side": "left", "offset": [0, 0.2], "align": true, "embed": 0.2 },
      "rotation": [0, 0, -25], "mirror": true, "blend": 0.02, "material": { "color": "skin" } } },
  { "op": "update_part", "id": "nose", "set": {
      "shape": { "type": "cone", "height": 0.09, "radius": 0.03 },
      "attach": { "to": "head", "side": "front", "offset": [0, -0.1], "align": true, "embed": 0.2 } } }
]

preview_motion { "clip": "walk" }:

preview_effect on the torch template's fire preset:

Critic output looks like this (from a deliberately broken edit):

size 1.00 × 1.32 × 0.46 m · 31,412 triangles · 2 body islands · built in 226 ms
ERROR [floating] orb is not connected to the rest of the body — use attach, raise embed, or mark it separate if it should be its own mesh
WARN [asymmetric] declared X symmetry is off by 1.3 cm on average; worst: orb (43.1 cm) — use mirror: true instead of hand-placing both sides

MCP tools

The scene document

Meters, +Y up, the model faces +Z, the model's left is +X. The full reference is in src/guide.ts (the text the guide tool returns).

• Shapes: sphere, ellipsoid, box, capsule, cylinder, cone (both optionally faceted with sides), torus, prism, tube (a swept tube with per-point radius, for tails, limbs, horns), and mesh (an imported GLB or OBJ).

• Combining: add with a smooth blend radius, carve, intersect; pattern (spots, stripes, noise, gradient), detail (surface displacement).

• Sculpts: inflate, dent, flatten, crease, noise, anchored to a part and side or a point.

• Clips: idle, walk, run, hop, fly, swim, drive, spin, hover, wave, nod, or keyframes, with keyframe tracks layered on top.

• Effects: fire, smoke, sparks, magic, explosion, dust, snow, rain, bubbles, heal. Every parameter can be overridden, and the particle paths are closed-form, so loops are exactly periodic.

CLI

clayform templates
clayform render biped --mode parts -o biped.png
clayform inspect my-scene.clay.json      # exit code 2 when critics report errors
clayform export my-scene.clay.json -o hero.glb --triangles 3000
clayform motion quadruped walk -o walk.png
clayform effect torch -o fire.png        # sprite sheet + .json + .preview.png

As a library

import { getTemplate, buildScene, critique, renderSheet, simplifyBuild, exportGlb } from 'clayform';

const build = buildScene(getTemplate('robot')!.scene);
console.log(critique(build).issues);
const png = renderSheet(build, { mode: 'parts' }).png;
const glb = exportGlb(await simplifyBuild(build, { triangles: 4000 })).glb;

How it works

1. Resolve parts in dependency order. Attached parts are placed by sphere-tracing the target's own distance field from the requested world side (without an offset, the extreme point that way), then sunk in by embed. Mirror twins are exact reflections.

2. Mesh the signed distance field (smooth-min unions, carves, intersections, sculpt modifiers) with surface nets on a block-culled grid. Only the shell near the surface is sampled.

3. Attribute every vertex: normal from the field gradient, ambient occlusion from the field, blended part color and pattern, dominant part, and skin weights restricted to the dominant part's parent and children.

4. See: a deferred software rasterizer (triangle ids + barycentrics, then one shading pass) draws the mesh, an analytic ground plane, a projected key shadow and a soft contact shadow. Labels use a built-in 5×7 bitmap font.

5. Measure: connected components, the volume centroid against the ground-contact hull, mirrored field sampling, and per-part visibility and thickness.

6. Export: quadric simplification (meshoptimizer) that keeps color, normal and material borders, then GLB with one primitive per material, a joint per part, and sampled animations.

Documentation

The same pages, with every image, are at clayform.sadelabs.site.

• Getting started · Concepts · MCP tools · Critics

• Animation · Effects · Export · CLI and library

• Matching a reference · Architecture · FAQ · Scene reference · Templates

• Layouts · Part library · Format stability · Showcase rules

• JSON Schema for .clay.json files: schema/clayform.schema.json

Showcase

Projects made with Clayform are listed at clayform.sadelabs.site/showcase. The first is Cargo Century, a browser transport tycoon whose 118 buildings, industries, stations, trees and vehicles are all Clayform scenes.

Made something with it? Send it in, or open a pull request with a small JSON file (the rules).

Limits (today)

• The look is stylized: smooth and clay-like, colored per vertex or in a baked texture. Material presets add normal and roughness maps, but nothing is photoreal. Hard mechanical edges are rounded at the cell size unless edges is sharp, so raise resolution for crisp props.

• It does not generate organic detail from a text or image model yet. You can import a mesh made elsewhere (mesh shape, GLB or OBJ) and keep working on it. Built-in hand-off to an image-to-3D model is on the roadmap.

• Animation is procedural plus keyframes on rigid parts: feet and arms use IK, characters can export humanoid bone names for retargeting, faces are morph targets and cloth ripples as a baked wave. Limbs bend only where parts meet. Layouts settle items straight down, but there is no rigid-body or cloth simulation: nothing tips, slides or collides while it moves. Motion critics check ground contact, sliding feet and parts passing through each other.

• The renderer is software rasterization with a shadow map. beauty makes clean pictures for a README or a store page, but there is no global illumination, glass or subsurface light.

• Nobody has run the bench yet (bench/), so this README makes no quality comparison.

Roadmap

Next up: image-to-3D hand-off (v0.4) and a published bench (v0.9). See ROADMAP.md, milestones and the changelog.

Development

npm test                              # includes the Khronos glTF validator and runs every docs example
npm run check                         # types
npx tsx scripts/gallery.ts            # regenerate docs/gallery.png
npx tsx scripts/docs-images.ts        # regenerate the README images
npx tsx scripts/gen-docs.ts           # regenerate docs/reference.md, docs/templates.md, the JSON Schema
npx tsx scripts/bench.ts <dir>        # score a bench run

See CONTRIBUTING.md.

License

Apache-2.0 © Sezgin Kipel