The development kit for Valve's Source engine is now available for free, the developer has confirmed.
Gamers have in fact been able to play mods made using the engine without charge since the release last year of Valve's free co-op shooter Alien Swarm. Now Rock Paper Shotgun reports that the developer has gone further and made the Source SDK completely free, following the news earlier this week that multiplayer shooter Team Fortress 2 was switching to the free-to-play model.
The news comes from Reddit, where one user – also lead playtester on Source mods Zombie Panic Source and No More Room In Hell – asked TF2 developer Robin Walker if buying an item in the game's virtual store, Mann Co, would give access to the SDK.
"Yep," Walker replied. "That said, your email has triggered a process here that made us re-examine that, and we're just going to go ahead and make the Source SDK freely available. Thanks for making us better!"
Pressed for further comment, Walker said: "We are in the process of getting it done. It's a bit messy because we have multiple versions of the SDK, and there's some dependencies we need to shake out."
Source first appeared in 2004, with the release of multiplayer shooter Counter-Strike: Source, with Half-Life 2 following shortly after. Since then it has been used in an enormous variety of games and mods. Those interested in the Source SDK should head to its official website.
Source: Rock Paper Shotgun