SpringRTS

Spring Engine (also known as SpringRTS or formerly TA Spring), is a game engine for real-time strategy (RTS) video games originally created by Stefan Johansson and Robin Westberg, members of the Swedish Yankspankers game clan. Originally intended to bring the gameplay experience of Total Annihilation into three dimensions, the engine has since evolved to support a plethora of more modern and more flexible features, including built-in high-level extensibility through a Lua scripting interface. The core game engine is free and open-source software, subject to the terms of the GNU General Public License version 2.

Since 2005 the Spring Engine is being developed by The Spring Community. The project has surpassed its initial goal to have the game run the mods and third-party units from Total Annihilation, and has evolved into a more general RTS engine. Most of the games running on the engine (as of December 2010) are focused on multiplayer gameplay. There are also currently a number of single player missions, built on frameworks utilizing the engine's Lua scripting capabilities. There are also a large number of skirmish AIs, allowing for offline play or extra players in an online game.