The Quake engine is the game engine developed by id Software to power their 1996 video game Quake. It featured true 3D real-time rendering and is now licensed under the terms of the GNU General Public License (GPL).After release it immediately forked, as did the level design. Much of the engine remained in Quake II and Quake III Arena. The Quake engine, like the Doom engine, used binary space partitioning (BSP) to optimise the world rendering.