Williams has become the first team to reveal its 2015 contender, ahead of the first test of the new campaign.
Ahead of Force India's livery launch on Wednesday, Williams - which placed third in last year's Constructors' Championship - showed off its FW37, which features a revised front nose to comply with the 2015 regulations.
The FW37 will be piloted by Felipe Massa and Valtteri Bottas, with the team again powered by Mercedes.
"The notion for the FW37 was to look closely at the FW36 and its performances," said Chief Technical Officer Pat Symonds.
"We then went about recognising what had worked well and identifying and resolving the areas that we felt needed to be improved. Although the aerodynamics of the car were impressive there is always room for improvement particularly as we handle the new 2015 nose regulations
"The design of the FW37 has stemmed from the performance of the FW36 but the conceptual ideas came long before the 2014 successes.
"The first conceptual stage of the FW37 came before the FW36 had turned a wheel. The main element to this is understanding the rule changes and how they will affect the design of the car, from here we can start see if our ideas will fit within the regulations."
There has been minor amendments to the Martini-based livery, with new sponsors Rexona, Avanade and Hackett appearing on the car.
Williams also revealed on Tuesday that the car fired up for the first time at their factory in Grove.