Stargate Prefab file

The Source SDK is a software development kit compiled by Valve Corporation that is used to create games or mods for the Source engine. Games like Left 4 Dead, Left 4 Dead 2, Counter Strike: Global Offensive, and Portal 2 are packaged with their own set of 'Authoring Tools' that are tailored for their specific engine builds and come packaged with the game on Steam. These games use most of the same programs below, but the source code can not be dumped. In 2013, an update was released for Source SDK that allowed users to build OS X and Linux versions of their mods. Additionally, support was added for Valve's new Steampipe content distribution system as well as the Oculus Rift. The Source SDK currently has three engine versions. A user can choose the 2006 version of the Source engine, which is only used by Half-Life: Source, Half-Life Deathmatch: Source, and various mods built on old Source 2006 code. All other Source games were updated to the most recent 2009 version of the Source engine.