> The illusions are created when a 3D object is translated into 2D, and
> some of the rules are broken. Because of this, Escher's basic 3D illusions
> (as well as a few of Dali's) cannot work in 3D. We have to come up with
> something based on his ideas, but new, for the new medium.
>
> But you guys keep missing the point: computer graphics is _not_ 3d.
> It's all 2d _projections_ of stuff.
No, that's not true. Using the logic that the display system can't
display anything but 2D (I assume that's what you're saying) just doesn't
hold water. If that were the case, then humans can't see anything but 2d,
since everything they see is projected by the leses in their eyes onto their
retina, which is 2D. What makes something 3D is the vision related
kinesthetic ability to move your point of view, and watch how the object
being observed changes its aspect ratio. Higher degrees of change
indicate a closer object. Once an object is within ten or twelve feet,
the stereoscopic capabilities of the human eyes (for those of use that
have two working ones) start to provide more 3D information, but we can
put a stereoscopic display system on a computer. That's what a HMD is.
Precisely what makes us able to see and comprehend 3D is what breaks most
of Escher's illusions. Once the point of view moves, the object falls
apart. As an aside, this may demonstrate a political message Escher may
have been trying to put across: If someone can control your point of
view, they can make you believe things which are completely untrue.
> Just because you can't build a 3d
> model of many Escher works, does _not_ mean you can't create
> continuously moving 2d perspective illusions which resemble his works.
> There is probably a mathematically correct way to do this. Even if
> there isn't, it can probably be simulated through extra processing of
> the viewer's perspective as he/she moves. So you run out of illusion
> after traversing 180 degrees or whatever. Big deal, you can always
> put up a wall to block the user from moving any farther than that.
Oh, sure. Put up a 2D Escher on the wall of a 3D room. Is this art? All
that this approach seems to be doing is trying to reproduce 2D illusions
in a 3D area. Like in Doom, the 2D-ness of the objects in the 3D area
becomes apparent when you slide back and forth. Every 2D object turns to
face you, and it breaks the illusion that is created when you stand
still. That isn't 3D. It's just a simple trick which demonstrates
intellectual laziness.
> I suggest that you Escher guys dig deeper on this one. Read some
> books on perspective tricks, and apply some savvy about computer
> graphics transformations. Deal with the issues head-on; nobody has
> _proven_ that it cannot be done. I'd do it myself, but as you well
> know, I'm too into Surrealism at present. If you wait on me to "put
> up or shut up," you will be waiting awhile. :-)
Because I talk about Escher, I'm and "Escher guy" now? Somehow you are
the one to be telling me I should be trying harder to accomplish
something that you think is worthwhile and I don't? I usually get paid to
do that. The "put up or shut up" idea seems to be the agreeable term,
here. You want to try to prove 2D Escher illusions can be done in 3D,
then you do it. I'm already satisfied that they can't. I'd rather spend
my time finding new 3D illusory methods which can be applied in the
spirit of Escher, and labeled "Esh" illusions.
--- Andrew C. Esh mailto:andrew_esh@cnt.com Computer Network Technology andrewes@mtn.org (finger for PGP key) 6500 Wedgwood Road 612.550.8000 (main) Maple Grove MN 55311 612.550.8229 (direct) <A HREF="http://www.mtn.org/~andrewes">ACE Home Page</A>