The team initially did not have access to the source code until Bethesda cleared the security of it. Obsidian submitted a three-page pitch to Bethesda for the project, which they named ' Fallout: Sin City.' The game was later renamed to ' Fallout: New Vegas.'
East Coast, Obsidian set the game in the American West. It was specifically designed to be more of an expansion rather than a sequel Obsidian, however, saw the project as akin to the Grand Theft Auto titles Vice City and San Andreas - not numbered entries, but still full games in their own right. They knew the game would not be a direct, traditional sequel to Fallout 3, and it was referred to as ' Fallout 3.5' within Obsidian. Discussions for New Vegas began between Obsidian and Bethesda in 2008/09.
