Actually I have projected video onto the floor many times.
If you are going to dance in the image, shinbusters are the way to go.
Need to keep most of the light off the deck.
Choice of image is very important. The best seems have a lot of light or
white in it. Details can be hard to come by. I doubt shining up the
floor will help too much - as in trying to add to the reflectivity. I've
had the best results with black and white images edited with an eye
towards the contrast with the black floor. Dancing in video snow is
pretty cool too.
If you can change the audience perspective, the higher the better.
Hope that helps!
