When I was in high school, my dad showed me a magazine ad he found that featured a random dot stereogram. I was blown away when I saw the effect, tried to figure out how it worked, and used it as geometry exercise. I even brought it to school to show in my math class.
Then, a few years later, these things hit the mainstream, big time. SIS images were all over the place, and books with these images starting selling well.
My friends and I wanted to do something unique with this idea, so we made the world's first RDS animation. I wrote a tool for generating the 3D effect, and Patrick a fast player to show the thing on the then very slow PCs.
Making SIS images requires a pattern image that will be repeated in vertical stripes, and a B&W depth image (where the darkness of each pixel corresponds to the distance from the viewers eye to the object - the nearer the object, the brighter the pixel).
To get the depth image, I modified the open-source raytracing software Povray to write the zbuffer to disk as a greyscale file, and then Christian took a model of the USS enterprise, made it turn in a circle, we threw away the raytracer output, and used the zbuffer frames as depth image input into the stereogram generator. Unfortunately, the result won't play on any modern computer so I can't post it here.
When it was all done, we offered it to a publisher. They required us to write a manual for it, so that it could be sold as a book instead of software (which reduced the VAT from 15% to 7%, clearly our publisher had some solid priorities), and grudgingly agreed to press 5000 units if we also promised to.... make a book, of which they would print 200,000 copies. Within a week.
We spent the next few days feverishly trying to come up with the 80 images they wanted, not paying much attention to quality. To get depth images, we spray-painted random objects (think the $2 "a day at the zoo" plastic toy kit) white and put them on a flatbed scanner. The reflection brightness depends on the distance from the glass, so this approach worked quite well. At one point I was eating a banana, and half way into it grabbed the spray can, went outside, and made the neighbors wonder if they should call someone to get us some professional help. The hidden banana picture became my favorite one in the book.
We ended up getting it done, learned something about the special treatment of "book club editions" for the purpose of author royalties (bad news, of course), but then got almost a dozen more contracts for additional books. The one with the best images, "Phantastische Photografie", sold the fewest copies, of course - 3000 or so, mostly because by the time it came out, the hype had passed.
We also did some advertising, including for the Nuremburg airport, a company that made door locks, bathroom fixtures, playing cars (company name: ASS. No kidding.) and a PR campaign for PVC, millions of copies of which ended up in an issue of the german magazine "Der Spiegel". Fun stuff.
About half way along the way I figured out a special technique to get more control over how the transition from one stripe to the next looked. The trick was to make multiple passes of each image, where we manually retouched away anything that looked ugly. The paint program we were using was marking all the changes in the alpha mask of the image. Our tool then used this information to propagate these changes to the copies of the stripe, reversing the damage the retouching did to the 3d effect.
The pictures below were all generated that way. Except for the amazon listing.. that's our first, crappy book. I can't believe these still exist.
