BMW partnered with Nvidia to build a digital replica of its soon-to-open EV factory. The tech is saving them millions—and a lot of headaches. Building a car factory is one of the most complex and expensive design projects imaginable. The factory itself is a giant machine where thousands of human workers, robots, and thingamajigs must move in a perfectly choreographed ballet to turn 30,000 individual parts into one automobile, at a rate of one car per minute.