Doc O'Leary schrieb:
Another fine
example is 3D TV or holograms. Yes, there are people trying to get
there, but they don’t exist in *any* sense as their science fiction
promise.

Holograms is actually one of the worst cases.

It seems that very many SF authors simply do not understand
the properties of real holograms at all.

A hologram consists of an interference pattern. When directed
light falls on that pattern, 3D objects can be seen.

One point that SF authors or directors routinely miss is that you
cannot see anything of the hologram if you are not looking at
the interference pattern. A hologram cannot absorb, bend or
refract light anywhere else (so the Doctor from Voyager is out).

It is also not possible to have 3D projector that, simply by
projecting light, can make something appear in thin air that can
be viewed at an angle from the projector. So, forget about R2D2
pojecting the picture of Princess Leia.