I wanted to include an animation( small movie .avi)in the background. That is easy to do,but I can't reduce the size so that it would fit the size of a tv ,as if someone is looking at the tv and can watch the animation that I've imported... Any solution?

Easiest thing i can think of would be to make the TV screen a separate material group (if it's not already), and use the 'movie' node into the appropriate inputs ni the material room. That way, the movie is played out for real, rather than trying to fiddle with it in the background setting. Never actually tried this myself, so don't know how it goes about resizing the thing, but it shoudl work... friendlyrogue

Thanks a lot ! I'll try ;)