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Moriash Moreau: My Second Life
Sunday, August 14, 2005
Paris in Stereo
Laura, Chrestomanci, and I killed a little time in Paris sim today, and I took a few pictures. Get ready for some eye strain: they're all in cross-eyed stereo.

First, no trip to Paris would be complete without a trip to the Eiffel Tower. This is no less true for the virtual version. The South Paris sim's model is impressive, even if it is at a reduced scale. This stereo image came out a bit eye-watering, unfortunately, due to the movement of the clouds in the background. Lesson learned: shorten the viewing distance to below 160 meters or so when looking upward into the Second Life sky. The cloud layer starts at around there, and the clouds move quickly in the mercurial, time-compressed weather of Second Life. (I often have similar problems with the SL wind violently whipping around the trees in the background. Fortunately, South Paris sim opted to use prim trees instead of the canned SL trees.) Of course, if your subject is already near the cloud level, this will present problems. Note to self: check the Debug menu for cloud rendering options.

Here's one of the many fountains in the Paris sims. I don't know if this is modeled after a RL fountain in RL Paris, but I found it impressive nonetheless. Sadly, the animated water introduced its own motion (and thus its own confusing parallax data), so this one is a bit nausea inducing as well.

South Paris sim hosts its own miniature version of the Louvre. Laura Ingersoll tells me that it's a close facsimile of the really thing. It looks impressive, in any case.

If anyone is interested in the technical aspect, I introduced an especially wide (at a guess, I'd say couple meters- it's hard to tell for certain with the client camera controls) distance between the left and right eye views for this one. (Actually, most of the stereo images I've taken are at a little wider than normal eye separation, but this one was extreme.) Normal stereo vision for depth perception stops working beyond a few tens of feet. Further away than that, and the parallax differences between left and right eye views are too small for us to detect. So we're left with an apparently flat view, and must rely on other visual cues to give us an idea of scale and distance. Stereo images are designed to capture the views for each eye, and thus have similar problems for apparent depth. By increasing the distance between the views, we increase the parralax differences, and therefore increase the distance in which our stereo depth perception works. This gives us a "God's eye view" of our subject, maintaining the illusion of depth even over the large distances (on the order of a couple hundred meters in this case). But it also makes everything look like a scale model to us puny humans, who are trained to deal with distances measured via the normal three-or-so inches between our eyes.

For comparison, here is the same shot, but taken with a narrower (about half as wide) separation. Note the comparative lack of depth.

I'm seriously considering making a how-to page for creating Second Life stereo images, if anyone is interested. Please drop me a comment if you'd like to know how I do this. It's a simple enough process, but there are a couple of pitfalls and tricks I could pass on, anyway. I can also make a page describing how to view them, if folks are having trouble.

Inside the Louvre, we surveyed the works of art. Naturally, the collection is smaller than the RL equivalent. But there are still some amazing pieces of original artwork inside, many of which are for sale. Each of us found one or two pieces that we contemplated for quite a while. And each of us saw a few that made us think "Huh?" or "I could have done that!" I even saw one display that pissed me off, for a variety of reasons I won't go into. Granted, ticking me off isn't all that difficult (for much the same metaphorical reasons as pushing someone off a balance beam in a typhoon isn't all that difficult), but one of the purposes of art is to invoke an emotional response in the viewer. Mission accomplished. The broad range of experience offered by a real life art museum has been fully captured in Second Life.

I refrained from taking too many pictures of the 2-D pieces that were for sale, and I won't be posting the few that I did snap. It feels too much like stealing. But I did capture a couple of the 3-D sculptures in stereo. Trust me, they're much more impressive in person, where they can be examined from more than one angle. Go see them for yourself!

Here is an interesting piece by Curt Kongo, titled "Icon." This image also appears in a few of his amazing paintings, as does the crooked shack that can be seen in the painting in the background. I'm not certain what these images mean to the artist, however. I'm an engineer, and am thus ill equipped to understand such things. This piece is for sale, if anyone needs an impressive sculpture for their virtual gardens or lobbies.

The next one is called "Dual Polyhedra: Cube and Octahedron", and was created by a RL math grad student named Seifert Surface. Seifert has donated this piece for permanent display in the Louvre. I've seen a few of his other works around, and I've always been impressed by both their beauty and their mathematical precision. He's also created a faithful reproduction of the old "gravity vortex" tourist trap illusion that must be seen to be believed. It's currently on temporary display on the second floor of the Librarium in Abitibi.

Oy! Answered one of my questions, how to precisly rack the camera, as in "you don't!" At least your text implies that you just move and look at the result!
Thanks, Orcpac7 Hokkigai
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