I built cat., a free browser physics sandbox, with Claude Code

I built **cat.**, a small 3D browser game where you’re a Norwegian forest cat in a cluttered house while the owner works from home. You can knock glasses and vases off tables, scratch furniture, unspool toilet paper, jump onto furniture, and meow at closed doors. Breakable objects fracture on impact, and an incident report records the damage as the owner’s patience runs out. **Claude Code helped me write and refine the game’s code**, including the character controller, glass-fracture system, and incident report. The stack is TypeScript, Three.js, and Rapier physics. A concrete challenge during development was distinguishing a paw impulse from a collision: glass should fly intact after a swat, then break when it hits something. Other work has involved landing clearance, camera collisions, and keeping repeated effects affordable on phones. The cat model started as a Meshy generation and was rebuilt, rigged, and animated in Blender. Furniture uses CC0 Poly Haven assets, and sounds…