Plans for a successor to the original Source engine began following the release of Half-Life 2: Episode Two in 2007.[1][2] The first engine tech demo was created in 2010 by remaking a map from Left 4 Dead 2.[2] Images of this were leaked onto the internet in early 2014.[3] 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.[4] Source 2 was first made available to the public via Steam Workshop tools for Dota 2 in 2014 prior to it being officially announced at the 2015 Game Developers Conference.[5] There, Valve stated their intent for it was to allow for content to be created more efficiently.[1][6][7][8] 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.[4][9][10]