Good idea Bingo quite like that...

If anyone is just plain curious 3-D projection is possible but star wars projection is pure sci-fi and still not possible.

The leading cutting edge 3-D projection is done by a company called musion
http://www.musion.co.uk/

and is based on an old theater trick called pepper's ghost.

http://en.wikipedia.org/wiki/Pepper's_ghost

I was lucky enough to see it in action on demo and it looks great but it's not quite star wars yet... We have a long way to go as we are just re-using old theater tricks but it still looks cool :)

I don't want to derail the thread but perhaps people might be interested so it seemed relevant to ground in reality of the techniques used today to try and accomplish an illusion of 3-D projection without mapping onto an object face with multiple projectors (curved wall or sphere for instance).

Light coming from underneath=pure sci-fi

But to ground it in some kind of reality to be totally believable as a projection it is missing a sense of light source or where the projection is coming from even though it is pure sci-fi which I think Bingo has rightly pointed out.