the game's open world setting was modelled on los angeles and other areas of southern california. much of the development work constituted the open world's creation, and the proprietary rockstar advanced game engine (rage) was overhauled to increase its draw distance rendering capabilities. key team members conducted field trips around southern california to gather research and footage, and google maps projections of los angeles were used to help design the city's road networks. for the first time in the series, players control three protagonists throughout the single-player mode. the team found the multiple protagonist design a fundamental change to the gameplay and narrative devices. they refined the shooting and driving mechanics and tightened the narrative's pacing and scope.