Step 1 of developing a car is giving a piece of paper and a pencil to a design artist. Then when the management likes it, they give him clay. Then the 1/2 scale clay model gets given to the engineers and management says "ok, make it work, but don't you dare change an external dimension. There better be trunk space, head space, shoulder room, and it better be fast and get great fuel mileage. And have a good stereo too."