Cat Breads

It started as an experiment: modelling organic shapes with signed distance fields in Blender 5.2. A small numpy toolkit of primitives, smooth booleans, gyroid lattices and noise warps, sampled on a grid and meshed with the OpenVDB module that ships inside Blender's Python, so there was nothing to install. Then my daughter drew 23 "Cat Breads" on index cards, and the experiment had its subject.

Every card became a cat: a smooth union of coloured SDF parts with paint layers for stripes, patches, eyes and mouths, baked into vertex colours so nothing needs a UV or a texture. The 23 cats are rigged with bones derived from the parts that built them, exported as Draco GLBs (the whole cast is about 5 MB) and placed in a procedural Three.js lounge that reflows to the screen. On her iPad, tap a cat and it hops, meows and looks at your finger. Double-tap the floor and a treat drops, and the nearest free cat comes to eat it. Night mode, glowing eyes, felted-fuzz shaders, ripples on the floor.

The lounge was finished and completely silent until the Comfy Cloud MCP: from the Claude Code session, one ElevenLabs sound-generation call per cat (a bell for the Lucky Cat, a buzz for the Bumble Cat), ACE-Step for the ambient loop, ffmpeg to trim and level, without leaving the editor. The 55-second demo tells that story, narrated in my own voice cloned with Chatterbox on Comfy Cloud. The demo was itself produced by Claude Code with a Remotion demo studio: scripted captures of the lounge synced to the real voices by a marker frame, a replay of the MCP session, and a mastered mix.

Modelling: sdf.py is a vectorised numpy toolkit (primitives, TPMS lattices, smooth booleans, shells, twist, bend, repeat, mirror and noise warps, Perlin and fBm) sampled on a grid and meshed with Blender's OpenVDB module. A second route builds the same idea from Blender 5.2's native grid nodes with live sliders. A character is a Model of coloured parts plus paint layers; the colour at each vertex is the softmin-weighted colour of the nearest parts with the paint composited on top, baked to a vertex-colour attribute.

Rigging and web: bones come from the anatomy each cat records as it builds, and the idle motion is F-curve noise with independent phases per cat, so the group moves without a keyframe. export_web.py writes Draco GLBs decimated to about 24k vertices per part and a layout file. The Three.js page assembles a pose per frame (spot, cursor look, idle sway, then the move's offsets) and injects GLSL into the standard materials with onBeforeCompile, so felted fuzz, petting ripples, floor ripples and the lamp cone keep lighting, shadows and skinning intact.

Sound and the demo: the voices came through the Comfy Cloud MCP's partner_generate (ElevenLabs sound generation) and the loop from an ACE-Step 1.5 template, trimmed and loudness-normalised with ffmpeg. For the demo video, a scripted mode in the page flashes a marker frame and logs each press; Playwright records the full Chromium with Metal (the headless shell renders the room at under one frame per second); ffmpeg finds the marker so the silent recording lines up with the real voices; a Remotion studio adds timed audio cues, music ducking and a terminal-replay scene; the narration is a Chatterbox clone checked with Whisper and levelled with a limiter; the mix is mastered to -14 LUFS.