CompuServe Messages

Phil, not so. I wouldn't consider my eyes exceptionally trained (I'm not an architect, engineer, or any other similar profession), yet even I'VE noticed the unrealism in animations (NOT STILLS!!) caused by straight perspective. For a long time, I didn't know what was causing the unrealism, only that it "felt unreal." It was only when I analyzed what I was seeing that I figured it out. But then, I'm good at that. I've read recently that there is still no suitable explanation for why the sun and moon appear larger to us near the horizon, but not larger to a camera. Some have claimed "atmospheric magnification," but that would affect a camera as well. The reason I have determined is that the sky does NOT appear as a hemisphere to us, but rather as a quite flattened semi-elipsoid — the zenith appears way closer to us than the horizon does. Go outside and look up and then to the horizon and you'll see what I mean. What we're seeing is the limits of the atmosphere above us, and that's nowhere near a hemisphere of 180 but rather a much smaller portion of a much larger sphere than we think we see — the tip of the spheroid, as it were. Well, the sun and moon always appear about the same size to us (approximately 1 second of arc in diameter), but when they're low in the sky they appear much further away since the sky itself seems further away, yet are the same size when the rules of perspective dictate that they should appear much smaller since they're further away. But a camera is not 3D and so does not see this apparent difference in the distance in the sky based on ascension. You can verify this by staring at a rising or setting moon that is very close to the horizon and thus looks quite large, for long enough to form an afterimage on your retina. Then look up, and you'll see that the afterimage appears the normal size of the moon as it would be at that height in the sky, because the same size image is now projected by your retina onto a sky that appears much closer than at the horizon. Moral: for the most in realism, don't map CLDMAP1.TGA to a hemisphere, or if you do, flatten it considerably (2D Scale it vertically to about 33%). Of course, link it to your camera so that the zenith always remains overhead, but also Link Info it to remove the rotational linkages.