Valve has decided to make its Source SDK free for all users, rather than require at least one Source title be purchased to obtain access to the engine.

Steam just released the Source SDK for 2013, adding support to Macintosh OS X and Linux, as well as support for Oculus Rift, thereby introducing Virtual Reality to the engine.

Valve has confirmed that the Software Development Kit for its Source engine will be made available to the mod community when Half-Life 2 goes on sale, on November 16th. Eagle-eyed observers ...

Today Valve's Source Software Development Kit (SDK) was updated with the tools to create content for the games in The Orange Box. That means it is now possible to build new levels for Team ...