Simon Willison · 2026-09-05 · notable
Simon Willison — driving Blender from a coding agent on macOS
Simon Willison points a coding agent at a local Blender install on macOS and lets it write and render Python scene scripts. Three rounds took a pelican on a bicycle from a plain render to a sunset coastal scene.
Install Blender, tell a coding agent where it lives, and it writes the Python that builds and renders the scene.
What is it?
Simon Willison's setup runs the Blender desktop app in headless mode from a coding agent on macOS. His whole instruction is one line — use the already installed /Applications/Blender to render a scene of a pelican riding a bicycle — and the agent takes it from there. He used GPT-6 Astra on medium effort inside Codex in the ChatGPT macOS app.
How does it work?
Each round the agent writes a Python file that builds the scene, runs Blender with --background --python so no window is needed, and looks at the render before editing again. Willison shows three passes of the same pelican: a plain render at 2m39s, a beachside version with huts, parasols and balloons at 3m51s, and a sunset coastal scene with flowers, bunting and a sailboat at 5m59s. Movies come from rendering an image sequence and joining it with ffmpeg.
Why does it matter?
The write-up ends with a reusable Markdown skill called Blender Local, so a later prompt can name the skill instead of rediscovering the commands. The scene scripts, the .blend outputs, the skill file and the full agent transcript are all in a public GitHub repo, which makes the workflow something you can repeat rather than a one-off demo.
Who is it for?
developers experimenting with agent-driven 3D
Try it
/Applications/Blender.app/Contents/MacOS/Blender --background --python scene.py