Following up on news from earlier this week that Valve made Team Fortress 2 free-to-play, we now get word that the Source engine SDK will be free to all as well. Quoting Rock, Paper, Shotgun: "The Source Software Development Kit, for those of you who've never clicked the Tools tab in Steam, contains everything you'd need to make a mod, except for personal ambition. It has everything from the infamous Valve Hammer Editor to Face Posers and Model Viewers. At the moment, to gain access to the Source SDK you have to purchase a Source based game such as Half Life 2, or as the official website states, Team Fortress 2. Which is of course now free. [Valve's Robin Walker said], 'We are in the process of getting it all done. It’s a bit messy because we have multiple versions of the SDK, and there’s some dependencies we need to shake out. But yes, the gist of it is that we’re just going to go ahead and make the Source SDK freely available.'"