<blockquote><font class="small">In reply to:</font><hr /><p>The 'Star Gate' sequence in 2001. <p><hr /></p></p></blockquote><br /><br />Ah yes, the slit-scan technique. I bought the DVD release of "Robot", the first Tom Baker episode of Dr Who. They used slit-scan to produce a "time tunnel" effect for the credits, and there's a documentary showing how it is done. It's a laborious process, and 2001 of course had a much longer and more complex slit-scan sequence.<br /><br />A lot of the effects in that movie are superb. Jupiter, Earth, and the Moon are gorgeous. To achieve that luminous effect so critical to the suspension of disbelief, they actually painted them on glass, illuminated them from behind, and then filmed them against a black velvet backdrop. Unfortunately, it was not possible to get Saturn to look right (the rings revealed that the painting was actually flat), so they switched the setting to Jupiter. And now you know why. <img src="/images/icons/wink.gif" /><br /><br />The set for Discovery's centrifuge was amazing -- it actually was a cylinder, rotating as the actors walked. The camera was mounted on a track (which you can see, although they designed it to look as if it was part of the spaceship), allowing the actor to walk at the same rate that the cylinder was turning, with the camera tracking away at the same rate, creating the illusion that he was running along it and "gravity" was to the outside. A smaller rotating set was used aboard the Moon shuttle so the stewardess could appear to be walking around a Velcro surface to change orientation. It's a very simple but extremely effective practical effect.<br /><br />One of the drawbacks of modern CGI, in my opinion, is that practical effects are not used as often anymore. And though practical effects have their drawbacks (and limitations), they are often much more effective.<br /><br />For instance, if "2001" was made now, I would expect to see CGI hominids, a la the BBC's "Walking With Cavemen", which used a comb <div class="Discussion_UserSignature"> <p> </p><p><font color="#666699"><em>"People assume that time is a strict progression of cause to effect, but actually from a non-linear, non-subjective viewpoint it's more like a big ball of wibbly wobbly . . . timey wimey . . . stuff."</em> -- The Tenth Doctor, "Blink"</font></p> </div>