Erin Catto

Erin Catto is a physics-engine programmer, best known as the author of Box2D — the open-source 2D rigid-body physics engine embedded across the game-engine landscape (it is the 2D physics behind Phaser and Torque2D, among many others). He is the author of Box3D, the 3D successor released in 2026 box3d.

Catto is known in the field for his work on constraint solvers for real-time rigid-body simulation and for long-running GDC talks on physics for games. His engines’ design signatures — sequential-impulse / soft-constraint solvers, determinism, and a small permissive-licensed C core — carry from Box2D into Box3D.