iphwk@MTSUNIX1.BITNET (Bill Kinnersley) (02/07/89)
How does Coke-3D work? Would it be possible to make a Coke-3D animation for the Amiga? -- --Bill Kinnersley Physics Department Montana State University Bozeman, MT 59717 INTERNET: iphwk@terra.oscs.montana.edu BITNET: IPHWK@MTSUNIX1
ewhac@well.UUCP (Leo 'Bols Ewhac' Schwab) (02/09/89)
In article <8902071540.AA02699@terra.oscs.montana.edu> iphwk@MTSUNIX1.BITNET (Bill Kinnersley) writes: >How does Coke-3D work? Would it be possible to make a Coke-3D animation >for the Amiga? > Funny you should mention that. They've been discussing that one rather a lot over in comp.graphics. Basically, it depends rather heavily on a psychophysical artifact of the way your eye processes information. If the light level is bright, the information is sent to the brain quickly. If it's dim, it takes longer for the retina to "fire" and send the information to the brain. Therefore, when you darken the image received by one eye, the dark image will arrive at the brain later than the bright image. If things work out just right, the undarkened eye will be seeing the current frame just as the *previous* frame is being registered by the darkened eye. Now then. If you have a lot of horizontal motion, you will get a 3D effect, since the clear eye will see the current frame, and the darkened eye will see the previous frame, which is shifted horizontally due to the horizontal motion. Thus, you get the needed parallax to perceive 3D. In other words, it's extraordinarly cheap, and is *extremely* viewer-dependent. And yes, you can do this on the Amiga, though it will look just as cheap. _-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_ Leo L. Schwab -- The Guy in The Cape INET: well!ewhac@ucbvax.Berkeley.EDU \_ -_ Recumbent Bikes: UUCP: pacbell > !{well,unicom}!ewhac O----^o The Only Way To Fly. hplabs / (pronounced "AE-wack") "Work FOR? I don't work FOR anybody! I'm just having fun." -- The Doctor
aaron@madnix.UUCP (Aaron Avery) (02/09/89)
In article <8902071540.AA02699@terra.oscs.montana.edu> iphwk@MTSUNIX1.BITNET (Bill Kinnersley) writes: >How does Coke-3D work? Would it be possible to make a Coke-3D animation >for the Amiga? By 'panning' the camera from right to left all the time, the one darker lens fools the brain into creating a realistic 3d image from the changing perspective. If the lens were over the left eye, panning from left to right would do it. So, all you need to do to create a Coke-3D animation on the amiga is to keep the 'camera' moving from right to left while animating a 3D world. -- Aaron Avery, ASDG Inc. "A mime is a terrible thing to waste." -- Robin Williams ARPA: madnix!aaron@cs.wisc.edu {uunet|ncoast}!marque! UUCP: {harvard|rutgers|ucbvax}!uwvax!astroatc!nicmad!madnix!aaron
jmdavis@ihlpm.ATT.COM (Davis) (02/09/89)
In article <8902071540.AA02699@terra.oscs.montana.edu>, iphwk@MTSUNIX1.BITNET (Bill Kinnersley) writes: > How does Coke-3D work? Would it be possible to make a Coke-3D animation > for the Amiga? > "Coke-3D" works by "slowing" the light getting to one eye so that a rotating object/scene/etc. will present one angle to one eye before the other. The 3D effect disappears when the object stops rotating. The reason for "slowing" is that I am not sure whether the light itself is slowed (if it is, then I w_a_n_t some of that material) or just that the other lens is dark and it slows the eye's registration of the object on the retina (this seems much more likely). It should be possible to use this on an amiga, buy some coke, get the glasses, get your favorite rotating object demo (block AMIGA should be fine) and see what happens. You may want to vary the rotation rate to maximize the effect. Also, make sure the object is rotating from "slowed" eye to "fast" eye. This means it must rotate around the Y axis of the monitor. It may work better if the object isn't tilted while rotating (I believe the block AMIGA is tilted). ======= There are other 3-D technologies, but they involve more money. There is the vibrating mirror effect that was used by a now defunct (I believe) medical imaging company. Also, I have seen a rather interesting arrangement of lenses that when fit over an old Apple II+ (in this case) produced an interesting 3D effect. Both of these require no glasses to view. I can talk at length about the first, but the second one still baffles me. Why bring this up, well the second was produced by a "garage type" inventor in California, and if word gets out that people are interested, he may be able to revive his stuff. > -- > --Bill Kinnersley > Physics Department Montana State University Bozeman, MT 59717 ^^^^^^^^^^^^^^^^^^^ There was a discussion on sci.physics about "coke-3D" -- ---------------------------------------------------------------------------- Mike Davis ..!att!ihlpm!jmdavis char*p="char*p=%c%s%c;main(){printf(p,34,p,34);}";main(){printf(p,34,p,34);}
dan-hankins@cup.portal.com (Daniel B Hankins) (02/10/89)
It is entirely possible, and in fact not difficult at all, to obtain
on the Amiga the same kind of 3D effects observed during Superbowl
halftime.
The effect is based on a phenomenon known as the Pulfrich effect,
named after its discoverer. He discovered that when one eye is covered
with a dark glass, that a pendulum swinging left and right would appear to
take on a circular motion. The reason for this was discovered some time
later.
When light strikes the retina of the eye, a chemical reaction takes
place which causes a signal to be transmitted to the brain. There is a
measurable delay between the time the light strikes the retina and the time
that the reaction progresses far enough for the signal to be sent. As one
might expect, the speed of this reaction is in proportion to the energy
received. What this means in practical terms is that a dim light causes
the signal to be generated later than a bright light.
Suppose that wearing a dark glass over the right eye causes an
additional delay of 1/60th of a second in reception of any given signal.
Now suppose that you are watching the pendulum as it swings from left to
right. Your left eye sees where the pendulum is now, and your dimmer right
eye sees where the pendulum was 1/60th of a second ago - slightly to the
left of where it is now. To focus both eyes on the object, the right eye
must be focused slightly to the left of the focus of the left eye. Here's
a grossly exaggerated diagram:
direction of motion
-------------->
Pendulum 1/60th of a second ago -> * * <- Pendulum now
\ /
* <- apparent position of pendulum
/ \
^ ^
left eye right eye (dim)
So while swinging from left to right, the pendulum appears to be
closer than it actually is. While swinging from right to left, the
pendulum would appear to be farther away than it actually is. Voila! 3D
effect.
How to do this sort of thing on the Amiga is fairly clear: Close
objects should move from left to right, medium range object should be
stationary, and far objects should move from right to left. The dark lens
should be worn over the right eye.
One caution: prolonged usage of this technique can cause a splitting
headache (eyestrain) in some people, for the same reason that other stereo
vision techniques do.
Dan Hankinsejkst@cisunx.UUCP (Eric J. Kennedy) (02/11/89)
In article <3017@ihlpm.ATT.COM> jmdavis@ihlpm.ATT.COM (Davis) writes: >In article <8902071540.AA02699@terra.oscs.montana.edu>, iphwk@MTSUNIX1.BITNET (Bill Kinnersley) writes: >> How does Coke-3D work? Would it be possible to make a Coke-3D animation >> for the Amiga? >"Coke-3D" works by "slowing" the light getting to one eye so that a rotating >object/scene/etc. will present one angle to one eye before the other. The Actually, I think a more likely explanation is that Coke spent millions in advertising before the Super Bowl, promising all this wonderful new 3D technology. Millions of suckers went out and bought Coke, fattening the pockets of the owners of Coke yet more, and getting their 3D glasses--if they could. Millions of viewers sat around Millions of TV sets--with tens of thousands of pairs of 3D glasses. By the time Halftime rolled around, the combined effects of Coke caffeine, Bud, Bud Lite, and media hype all served to confuse viewers so much that in frantically passing around two pairs of 3D glasses among 15 people, nobody seemed to notice that the 3D effect was completely underwhelming. Well, at least that's how *I* think it works. -- Eric Kennedy ejkst@cisunx.UUCP