Show HN: Formally verified 3D CSG: Trust 93 lines spec, not 1000 lines AI code | Hacker News

A Hacker News demo introduced a formally verified 3D mesh intersection kernel implemented in Lean 4.

The system relies on a 93-line specification and machine-checked proofs, rather than trusting thousands of lines of AI-written code.

The author says AI heavily assisted development, but humans only need to trust the short spec and the Lean checker; the result also runs in the browser via WebAssembly.

The project highlights how formal verification can make 3D geometry and AI-assisted software development safer.