One related process that's gained some interest is the thought that one could apply a powder coat to a car that way.
My former employer actually built a facility to do that (attract the paint to the car via charging the car electrically) and it was (is) very stylish, all glass walls so you can see in during the painting process but since trials were completed it's stood deserted. I have been told the paint did not turn out well, it became too thin, extremely brittle and prone to cracking, especially in cold weather.
I hear it works well for other products so it's a bit strange why it wouldnt work for cars but the standards and tolerances in producing cars are of course entirely different from producing many other smaller and cheaper goods.
It was quite interesting to walk around in that section of the factory at night, only dimly lit, the most tranquille place you could find (well, in the paint shop at least, you can never completely escape the ventilation noise) and at the same time you knew it was the remnants of a failure. You could feel the energy they put into the design, they really thought it would work, it's too bad that it didnt, it would have been a kickass place to work in and show off for visitors.
I thought there was a coat added that was roughly the bodies color. Hence the engine bay and floor panels are painted the same color.
That is normal paint (well, one or more coats of paint) applied by spray gun, either by robots or humans. The primer (ED) is always grey, then depending on what colour the car is to be you add a base colour (if it's going to be red it can be white or pinkish) and then you add more layers of paint (and flakes etc) and then a clearcoat. It's important to cover all areas you think the customer might see, as well as wheel wells and floor panels, boot area (altough many volume manufacturers cheat on this) etc. The underside of the roof is seldom painted with more than a few whiffs though.
I'll detail our workflow (no it's not very secret
)
ED->inspection->sealant->interior noiseproofing->exterior noiseproofing->touch up primer->base coat->inspection->polish->paint coat(s)->clear coat->inspection->polish