This month BMW unveiled their iX Flow in a special color: Black—or white. Covered in E-ink panels, the car can switch hues at the press of a button:
So how did they do it? Because E-ink panels are flat and the car’s surfaces are anything but, they essentially went into the CAD model of the actual car, grabbed each piece of the surface, and used generative design to “unfold” the contours into flat sheets. They then used a lasercutter to shape the E-ink panels:
Ever the efficient Germans, BMW writes that the technology actually has a practical application:
“Heating of the vehicle and passenger compartment as a result of strong sunlight and high outside temperatures can be reduced by changing the exterior to a light colour. In cooler weather, a dark outer skin will help the vehicle to absorb noticeably more warmth from the sun.
"In both cases, selective colour changes can help to cut the amount of cooling and heating required from the vehicle’s air conditioning. This reduces the amount of energy the vehicle electrical system needs and with it also the vehicle’s fuel or electricity consumption. In an all-electric car, changing the colour in line with the weather can therefore also help to increase the range. In the interior, the technology could, for example, prevent the dashboard from heating up too much.”
In autobahn-less America, of course, you’d mainly hit the button after you blew past a speedtrap.
https://www.core77.com/posts/111438/BMWs-Color-Changing-Car