Karpathy Tests Claude Opus: Writes 5500 Lines of Code to Render 3D Scenes

jon_barron · x · 2026-08-05

Andrej Karpathy recently shared test results of using LLMs to generate complex 3D scenes. He provided Claude Opus with the opening paragraph of Lord of the Rings and a budget of around 1 million tokens ($10), asking for a Three.js render.

Opus spent about 2 hours writing 5,500 lines of code to procedurally render the story. Karpathy found it mindboggling that the model could place and orchestrate polygon assets in (x,y,z) coordinates and write animation code that actually worked. Separately, developer Rana Hanocka demonstrated using Thrixel MCP to let Claude create and iterate on 3D assets, assemble scenes, and wire up gameplay logic, creating a playable game with a single prompt.

Related event: Karpathy Tests Claude Opus to Generate 3D Movie(2 posts)→

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