PC games giant Valve has put a halt to two fan projects based on its IP.

As reported by GamesRadar, the company has issued a DMCA takedown request for Team Fortress: Source 2, a fan project that brought the popular multiplayer shooter to Valve's new engine. The developer, Amper Software, was doing so via Rust maker Facepunch's S&box project. Taking to Twitter, the studio said that this was the "nail in the coffin" for Team Fortress: Source 2.

"The TF2 assets have been ported to Source 2 without permission and are being redistributed by Amper Software in a game mode for Facepunch's S@box," Valve wrote in its DMCA notice to Amper.

"Facepunch has not licensed any Valve assets for S@box. The unauthorized porting and redistributing of Valve's assets without a license violates Valve's IP."

Meanwhile, another fan project – Portal 64 – is also coming to an end. Valve doesn't appear to have issued a DMCA takedown to the demake's developer, James Lambert, but in a Patreon post he wrote that he had been in conversations with Valve. This appears to be related to Lambert using "proprietary libraries", though it's not exactly clear what this means.

Valve has historically been open to fan projects; some, such as Portal: Revolution and the Black Mesa Half-Life remake are even available to buy on Steam.