A mechanical TV — the kind that makes an image with a Nipkow disk and a single lamp with some help from persistence of vision — is easy enough to wrap your head around. Moving that technique into the third dimension, though? That’s a bit of a head scratcher. Luckily for us [AncientJames] provides a simple visual explanation for how the magic happens.Instead of a disk doing a raster scan of the display, he’s using a rapidly-spinning drum with holes in it. In place of a single lamp, he’s got an array of LED matrix displays, each 32 pixels by 64 pixels in resolution. The trick is splitting the model up into a light field, so each hole projects its own image of the object at the proper angle.In this demo there are three matrix displays, though that does limit the viewing angle as they’re arranged as one half of a hexagonal prism — you’d need more screens to get a full 360. The effective resolution through the drum is only about 100 pixels by 48 pixels per eye, but that’s still enough to play DOOM with.This isn’t the first time this particular [Ancient] has got DOOM going on a volumetric display, and based on previous results, it probably won’t be the last time either. This implementation, which keeps the displays stationary and does not require a pricey laser projector, looks the most accessible to us, as long as you watch your fingers.