At Tesla's recent Investor Day presentation, Lars Moravy, the company's VP of Vehicle Engineering, revealed a startling new manufacturing technique that up-ends assembly line production. To explain how it works, Moravy first introduced this animation of how cars are currently built:

Traditional Method

Within that animation, you probably spotted the one physically impossible step that was only included to keep the animation short. It's this step:

Key Problem with Traditional Method

"I wish it went in like this," Moravy says of the interior, which is rendered as monolithic in the animation, "but there's actually people coming in and out of the car [to install it piecemeal]." Steps like that are emblematic of the problem with traditional assembly-line manufacturing. Once a car body is put together, only so many people can fit in it and around it to install components, which slows things down. Furthermore, a lot of time and energy is wasted as the 5-meter-long vehicle must be moved from station to station.

Thus Tesla is working on this "unboxed" method. It essentially boils down to breaking the car into subassemblies, each assembled by their own team and even painted separately, and these subassemblies don't come together until the very end:

Tesla's Proposed "Unboxed" Subassembly Method

The simple idea is that by breaking the car up into subassemblies, more bodies have room to assemble at once:

Like the company of Tesla itself, it's radical, crazy and no one has pulled this off. If anyone can, it's Tesla, and the potential payoff is huge: Moravy says this "unboxed" method of building a car can reduce costs "as much as 50%" and allow vehicles to be built in factories with 40% smaller footprints.

Here's the entire 5-minute presentation, which I found worth watching: