Plans for a successor to the original
Source engine began following the release of
Half-Life 2: Episode Two in 2007. The first engine tech demo was created in 2010 by remaking a map from
Left 4 Dead 2. At the 2014
Game Developers Conference, Valve employee Sergiy Migdalskiy showed off a Source 2 physics debugging tool being used in
Left 4 Dead 2. Source 2 was first made available via
Steam Workshop tools for
Dota 2 in 2014 prior to it being officially announced at the 2015 Game Developers Conference. There, Valve stated their intent for it was to allow for content to be created more efficiently. Valve also stated that it would support the
Vulkan graphics API and use a new in-house
physics engine called Rubikon, which would replace the need for the third-party
Havok tools.
Gabe Newell, president and founder of Valve, said that the company were prioritizing the development of their own games before they would release the engine and its
software development kit to the public. This was to ensure the highest quality for developers; he added that they were intending to make the engine free to use for game developers as long as the game is published on their
Steam service. In June 2015, Valve announced that the entirety of
Dota 2 would be ported over to Source 2 in an update called
Dota 2 Reborn.
Reborn was first released to the public as an opt-in beta update that same month before officially replacing the original client in September 2015, making it the first game to use the engine. Source 2 has also been used for Valve's
Artifact and
Dota Underlords, with the engine later being supported on
Android and
iOS for the latter. The engine also supports the creation of games in
virtual reality, being used in
SteamVR Home, the
Robot Repair tech demo within
The Lab, and
Half-Life: Alyx. Source 2 tools made specifically for creating content for
Half-Life: Alyx were released in May 2020. == Games ==