Open-source tool designs LEGO builds with more than 2,000 real pieces

AI models can now design LEGO builds with thousands of real pieces, creating programs that output detailed CAD files, with the assistance of open-source LDraw Nova. It can leverage general models like GPT-6 Astra and Claude Opus 5.5 to design elaborate builds from a prompt, such as the 2,175-piece Sakura Garden. The models use Python tools to write programs, which output the builds without placing every brick. None of the designs have been built with real bricks yet, though; developer Carlos Antelo says he “didn’t even try.”

“Give an AI agent a model idea. Guide it, let it build it,” according to the GitHub project’s README. The Sakura result arose from a prompt to Claude Opus 5.5 asking for “the most beautiful model that comes to your mind.” Antelo posted the project on Friday afternoon as the first release after getting the toolkit to work after three earlier attempts.

LDraw, according to Antelo, is a text format where each LEGO …