blender-code-film

Make a short 3D film in Blender written entirely in Python by an agent (Claude Fable 5.2, Claude Code, Codex): the shots and the look as data, a world built from code (procedural terrain, hundreds of instanced props, node materials, lights, haze), one camera per shot bound to timeline markers, a stills-first approval pass, a quarter-size draft, a contact-sheet audit, a fresh critic subagent, then the final render to PNG frames and an ffmpeg encode with an optional varg music bed. Includes a tested starter (scripts/film.py, a 9 s three-shot film) and the Blender 5.x traps that turn frames black. Use when someone asks for a Blender animation or film made with code or Python, "make a video in Blender with Claude", a 3D short, music video, toy commercial or product film rendered in Blender, a low-poly or storybook 3D film, or a remake of a viral Fable 5.2 Blender video. Not for previz that feeds Seedance (code-to-video-previz, varg-previz), three.js films in the browser (karpathy-3d-story, code-3d-explainer), recording a browser game (code-game-trailer), 2D motion graphics (hyperframes, kinetic-type-art) or AI-generated footage (varg-ai).

Blender film from code

An agent can make a finished 3D film without touching Blender's interface: it writes one Python file that builds the world, places the cameras and renders the frames. On the day Claude Fable 5.2 came out (2026-11-09) this was one of the most saved formats on X:

• @rileybrown: one prompt, live on stream. A desk room in Blender, the laptop screen showing a web page the model also built, 13 camera shots, golden hour to night to sunrise, graded, titled and scored. 4K rendered in 52 min on 10 rented GPUs for $5.75. 606k views and 6,165 bookmarks; his reply with the recipe alone got 812 bookmarks.
• @alexmichael: "made this entire video from scratch, writing Python to control Blender" (117k views).
• @kevin_t_ngo: a music video animated in Python and rendered in Blender; his earlier storybook film rebuilt a 2D code animation in 3D.

The starter in scripts/film.py is this skill's own test: a lantern orb drifts up a low-poly forest valley at dusk in three shots (wide, follow, reveal), with haze, sparks and a warm rim light. Nothing is downloaded.

1. Ask before building

Put these to the person (in their language) and wait:

1. Look: low-poly storybook (flat shading, warm lamps), stylized toon, or photoreal (Cycles, slower).
2. Length and frame: 9–30 s; 16:9 for X and YouTube, 9:16 for Reels and TikTok, 1:1 for a feed.
3. Sound: none, a music bed from varg (about $0.10 per track; quote it from estimate_cost), or sounds synthesized in code.
4. Render budget: this machine with Eevee (minutes), this machine with Cycles (hours with volumes), or a rented GPU farm for 4K Cycles (Riley's 52 min on 10 GPUs cost $5.75).

2. Set up

bash

blender --version || brew install --cask blender     # or the installer from blender.org
blender -b --factory-startup -P scripts/film.py -- --stills --draft --out render/stills

Always run headless (-b) with --factory-startup so the user's add-ons and preferences can't change the picture. Arguments after -- go to the script.

3. The film is data

Everything that changes the picture sits at the top of film.py:

• LOOK: the palette in linear RGB (sky, ground, materials, key and fill colors). One palette for the whole film; one warm key light and one cool fill; practical lights (lamps, the orb) for the rest.
• SHOTS: one row per shot with start/end frames, lens in mm, the camera's start and end position in metres, what it aims at (a moving point or an object), and key, the frame that --stills renders.
• The build_* functions: one per part of the world, in metres, seeded (--seed) so a re-render gives identical frames.

Write the beat sheet first (what happens in each shot, in one line), then turn it into SHOTS. Rebuild the whole scene from scratch on every run (read_factory_settings(use_empty=True)); never patch a saved .blend.

4. Building the world in code

• Ground you can ask about. Make terrain a Python function of (x, y) (ground_z in the starter) and build the mesh from it. Then every tree, rock and path sits on the ground exactly, with no ray casts.
• Hundreds of props, one mesh. Build a prototype once, create objects that share its mesh (bpy.data.objects.new(name, proto.data)), then delete the prototype. The starter places 420 trees this way.
• Keep the lens clear. Sample every camera move and keep props 5 m from it, or the first wide shot opens on a giant tree trunk (the starter's first render did).
• Materials are node trees set in code: Principled BSDF with Base Color, Roughness, Emission Color and Emission Strength. Dark albedos (below 0.05) read as black under a grazing sun; start near 0.1.
• Cameras: one camera per shot with a Track To constraint on an aim object, depth of field focused on it, and a timeline marker at the shot's first frame with marker.camera = cam. Keyframes from keyframe_insert are Bezier and already ease in and out.
• Sound in code if chosen: synthesize with numpy and write WAV beside the frames; mux.sh takes any audio.

5. Stills first, then motion

1. --stills --draft: one quarter-size still per shot (under 1 s each after the first run). Look at them.
2. Send the stills to a fresh critic (below). Fix, repeat.
3. --stills at full size: show the person and get a yes before any animation.
4. --draft: every frame at quarter size, then scripts/sheet.sh render/draft 12 makes a contact sheet of every 12th frame. Check: the camera never clips through geometry, nothing pops or flickers, no shot is empty, exposure holds across cuts, the subject stays in the frame.
5. Final: blender -b --factory-startup -P film.py -- --out render/final, or --shot <name> to redo one shot. Frames are PNGs, so a crash keeps every finished frame and one shot can be redone alone.
6. scripts/mux.sh render/final film.mp4 [music.mp3] encodes H.264 CRF 18, cuts the music to the film, fades it out over the last second and normalizes it to -14 LUFS.

6. The critic loop

The builder never grades its own work (a rule that spread with Fable 5.2 prompts such as @everestchris6's).

• After each round of stills or each draft, start a new subagent that has seen none of the work. Give it only the beat sheet and the images.
• It answers yes or no, then at most five problems ranked worst first, each with a fix in numbers ("camera 2 m lower", "key light 30% dimmer", "orb 20% smaller"), then what already works.
• Fix the worst problem first, render again, and ask a new critic. Repeat until yes.
• For taste (palette A or B, lens 24 or 40 mm), show a critic both versions labelled A and B and let it pick.

7. Eevee or Cycles

	Eevee	Cycles
Starter at 1920×1080	2.9 s/frame (96 samples, with haze)	not practical with haze
One 960×540 still, haze on	under 1 s	3 min 16 s (64 samples, Metal GPU, includes the first kernel compile)
One 960×540 still, haze off	under 1 s	about 1.5 s (48 samples, denoised)
Whole film at 960×540, haze off (216 frames)	2 min 29 s (0.7 s/frame)	8 min 19 s (2.3 s/frame, 48 samples)
Use for	stylized, low-poly, toon, drafts, most finals	glass, caustics, photoreal interiors, product shots

Volumes are what make Cycles slow: drop the haze (--no-haze) or render Cycles finals on a GPU farm. film.py --engine cycles switches Cycles to the GPU backend the machine has (Metal, OptiX, CUDA, HIP, oneAPI); with --factory-startup it would otherwise render on the CPU.

8. Traps in Blender 5.x (each one hit while testing this skill)

• A world volume turns the frame black. In Eevee the world's volume is infinite and swallows the sun and the sky at any density. Put haze in a large cube around the set instead (build_haze), and raise scene.eevee.volumetric_end past the set (default 100 m) or the far sky shows a clean band.
• A light inside a glowing mesh lights nothing. The mesh shadows its own lamp. Set obj.visible_shadow = False on the orb, bulb or lantern.
• action.fcurves no longer exists (Blender 5 actions have layers and slots). To edit curves use bpy_extras.anim_utils.action_get_channelbag_for_slot(obj.animation_data.action, obj.animation_data.action_slot).fcurves, or avoid it: default keys already ease.
• Engine ids changed. Eevee is BLENDER_EEVEE in 5.x and was BLENDER_EEVEE_NEXT in 4.2–4.x. Read the enum instead of hard-coding it (the starter does).
• Emission input names. Principled BSDF has Emission Color since 4.0 (older scripts set Emission).
• Material.use_nodes and World.use_nodes print deprecation warnings in 5.x; they still work until 6.0.

9. Briefs to start from

Short briefs that work as one prompt (fill the brackets; ask the section 1 questions first):

text

Make a [20]-second [16:9] film in Blender, entirely in Python, run headless. Low-poly storybook look,
flat shading, warm practical lights, soft haze. Story in [4] shots: [one line per shot]. One palette:
[cream, teal, warm orange]. Every model, material and texture from code, nothing downloaded. Stills of
every shot first; a fresh critic reviews them before any animation. Then a quarter-size draft and a contact
sheet, then the final at 1920x1080, then an MP4 with [a calm piano bed from varg].

text

Make a 15-second 90s-style toy commercial in Blender with Python: [the toy] on a turntable, a hero push-in,
two close-ups of [features], a glow moment, then a packshot. Plastic materials with clear-coat, a
glossy studio floor, three-point light plus one colored rim. No real brands. Stills first, critic loop, then
render and mux with an upbeat jingle bed.

text

Make a music video in Blender for [song.mp3]: measure the BPM, cut on the downbeats, drive the lights and one
hero object's scale from the kick. [Theme], [palette], [3-6] shots. Contact sheet every 12th frame before
the final render.

Files

• scripts/film.py: the starter film (world, shots, render modes --stills, --draft, --shot, --engine cycles, --samples, --percent, --no-haze, --seed). Replace the world and SHOTS with yours.
• scripts/sheet.sh: contact sheet of every Nth frame (frame numbers when ffmpeg has drawtext).
• scripts/mux.sh: frames (+ music) to MP4.

Related: code-to-video-previz (a Blender or three.js blockout that drives Seedance), code-game-trailer, code-3d-explainer, model-split-screen (Fable vs Opus, Eevee vs Cycles), video-sound, varg-ai.