blender-claymation

Blender claymation

Turn a short idea ("a penguin who lives in an igloo") into a ~20 second stop-motion clay film: a tabletop miniature built in real-world metres, a puppet made of lumpy clay primitives, a locked-off camera with shallow depth of field, and animation that moves in held steps like a real animator nudging clay between shots.

Everything is scripted: one Python scene file per film, rendered headless. Nothing needs the Blender UI.

Files in this skill

• scripts/claylib.py: clay material, lumpy primitives, lights, camera, easing, Boil jitter, constant-interpolation keys, CLI (cli()) and render entry point (run()).
• examples/igloo.py: character film. A penguin peeks out of an igloo, waddles out, catches a snowflake and waves.
• examples/clay_spark.py: desk-set film. A sleeping clay ball wakes, sprouts rays and hops onto books.
• scripts/blender.sh: finds Blender and runs a scene headless.
• scripts/encode.sh: 12 fps PNGs to a 24 fps mp4 with grain and vignette.
• scripts/contact_sheet.sh: tiles frames so you can review the story in one image.
• assets/player.html: video player page for an Artifact (autoplay, muted, loops).
• references/look-guide.md: what makes it read as clay, with numbers. Read it before building.
• references/recording-demo.md: optional OBS screen recording of the finished result.

Paths below are relative to this skill's directory ($SKILL). Work inside the user's project folder: put scene scripts in scenes/, frames in renders/<name>/, and finished videos in out/.

Workflow

Keep the user in the loop the way a small studio would, with short, warm updates: a one-line plan, a still when the set looks right, a note when the character moves, then the film.

1. Check tools

$SKILL/scripts/blender.sh finds Blender and fails with install hints if it's missing. You need Blender 4.2+ (tested on 5.2) and ffmpeg. Install as needed:

• macOS: brew install --cask blender
• Linux: sudo snap install blender --classic
• Windows: winget install BlenderFoundation.Blender

Cycles picks the GPU automatically (Metal, OptiX, CUDA, HIP, oneAPI) and falls back to CPU. On CPU, halve the resolution and samples.

2. Plan the short before writing code

20 s = 240 frames at 12 fps. Write a beat sheet in frame numbers: establishing hold (about 30 frames), character reveal, two or three story beats, and a button ending (happy pose, blink, hold). Give every beat anticipation, action and settle. Hold key poses 4–8 frames.

Stage it like a real set: one locked-off camera, a tabletop miniature in metres (character 5–10 cm tall, camera 0.5–0.9 m away, 50 mm lens), and a backdrop close behind.

3. Write the scene script

Copy the closest example into scenes/<name>.py and rewrite it for the new idea. Keep its structure:

1. OPTS = cli('<name>'), reset(), sc = setup_render(res=OPTS['res'], samples=OPTS['samples']), world(...)
2. Set: materials via clay(name, color, ...), geometry via sphere / rounded_box / cylinder with lumpy= displacement. Nothing perfectly smooth or perfectly straight.
3. Puppet: primitives parented under empties. Root at the feet, then body pivot, then head pivot; limbs hang off pivot empties so poses are just rotations. Eyes are glossy black beads. Blinks and expressions are replacement parts swapped by scale (1e-4 hides one), like real stop-motion faces.
4. Lights and camera: key, fill and rim area_lights, plus a practical (lamp glow, window, fairy-light bokeh from small emissive spheres). camera(loc, target, lens, fstop, focus).
5. Animation: for f in range(1, 241): compute the pose with seg / ease / ease_out_back, key() every animated property on every frame, add Boil jitter to puppets, flicker the key light ±1.2%. Then call constant_interp() and finally run(sc, OPTS).

The sprout, the hops and the snowflake landing on the beak in the examples show squash-and-stretch, arcs and props that follow a moving part.

4. Look-dev with cheap stills

$SKILL/scripts/blender.sh scenes/<name>.py --still 1 --res 960 540 --samples 32 --out renders/<name>_test

Render 4–6 frames that cover the story beats (a few seconds each on a recent GPU), then look at them. Tile them with ffmpeg hstack or vstack if that helps. Check these before any full render:

• Exposure. Clay washing out to pastel means too bright. Lower light energy or sc.view_settings.exposure.
• Contact. Feet, rays and limbs touch the ground rather than float or sink.
• Eyes. They read at thumbnail size.
• Composition. Horizon placement and lead room are right.
• Bokeh. Background practicals show as soft discs. A longer lens or lower f-stop gives bigger bokeh.

5. Render the full shot in the background

nohup $SKILL/scripts/blender.sh scenes/<name>.py --res 1600 900 --samples 80 --out renders/<name> > renders/<name>.log 2>&1 &
ls renders/<name> | wc -l   # progress

An Apple M4 Pro does about 6–7 s per frame at 1600×900 (240 frames ≈ 25–30 min). Run one render per GPU at a time, since two in parallel are slower than two in a row. When waiting on a render, match pgrep -x Blender (blender on Linux), not pgrep -f, which also matches your own watcher's command line. --range A B re-renders a slice after a fix.

6. Encode and review

$SKILL/scripts/encode.sh renders/<name> out/<name>.mp4
$SKILL/scripts/contact_sheet.sh renders/<name> out/<name>_sheet.jpg 20

Look at the contact sheet. Every beat should read, with no popping, floating or intersecting parts. Fix it and re-render only the affected range.

7. Present it

If the Artifact tool is available, copy assets/player.html to out/index.html, set its <title> and reel buttons, and publish it with the videos as supporting files (for example files: {"<name>.mp4": "out/<name>.mp4"}). In the desktop app, open it beside the chat (show_pane → artifact). Otherwise give the user the mp4 path.

8. Optional: record a demo

To make a screen recording of the finished film playing in the app, follow references/recording-demo.md. Record only the final playback, not the build.