A modder got Skate 3's physics, tricks and grinds running inside the 2009 Call of Duty: Modern Warfare 2. Walk around any map, hit J, and the soldier drops onto a board. The build is crazier than the clip. The base layer is IW4L, a from-scratch rewrite of the MW2 engine in Rust. On top of that sits a Rust engine that recreates Skate 3's physics, animation graphs and grind logic, and the soldier hands control to it when you hit the key. A retargeting layer maps the Skate 3 skater's bones onto…