Very interesting replies. I have no interest in doing that myself, just find it amazing it can be done.

That some of the backgrounds are "real" is helpful. Some of 'em look very, very authentic.

That some of them are models makes sense, too, though many aren't.

A combination of perceptive tricks, authentic backgrounds, and plain, raw software and computing power seem to be the what it's done.

And to think about 15 years ago I was in a CompUSA store looking at a monitor which had Winnie-the-Pooh flying a kite. The kite soared from the ground, up into the air, swirled and headed back to the ground.

The string stayed straight, no "steps", or jags in it. That was amazing.

Arf