You Can't Frustum and You Can't Frust Withoutum

That title is just a joke. Contra my graphics (and award-winning user interface design) instructor in college, it certainly is possible to discuss 3D projection without resorting to the term "frustum."

I'm a little confused about what kind of camera setup creates the best anaglyph images. All of the custom hardware setups I've read about people using either have identical cameras exactly side-by-side and pointing in the same direction,

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or a single camera mounted so it can slide right and left perpendicular to the direction of the lens,

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Either of these setups result in two images that reproduce the effect of looking at an object (a duck, say) with your eyes facing exactly the same direction:

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(Those are eyeballs at the bottom.)

And that's the kind of configuration I've been using for the anaglyph 3D graphics display: move the virtual camera slightly to the left and render the red channel, then move the virtual camera slightly to the right and render the blue and green channels.

But I think the way human vision actually works is that both eyeballs sort of independently point at whatever you're focusing on. Which is why when a butterfly flies up to you and lands on your nose you end up crossing your eyes. More like this:

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I think that's more like how I take 3D photos with my digital camera. I don't have a horizontally-sliding mount or two identical cameras, so I just take one picture pointing at an object, move over, and then take another pointing at the same object. I think the result should be more like looking at an object in real life, assuming the viewer is focusing where you expect them to be.

I'm going to try this out in my graphics setup and see how it works.

More 3D Photos

I did some more 3D stuff. Got a couple somewhat blurry ones around the house, and one in particular of some houseplants on the windowsill that came out really nice. Also a good shot outside the post office and one inside taken on my celly (a violation of the 3D PATRIOT Act X-Treme). And one of my blood getting drained by the vampires at the NY Blood Center.

I decided to put everything into a 3D set on Flickr.

More 3D Stuff

I don't know why this didn't occur to me before, but it's totally easy to take 3D pictures with a regular camera. I found a tutorial on how to do it, but it basically just boils down to dropping the green and blue channels out of the left eye image and the red out of the right and multiplying them together.

My first attempt was kind of wack, I think because the two images were too far apart and not parallel. It's my mouse and tea mug:



Then I took this picture of my bike, which I thought would be a good reference for my 3D pencil drawing. It came out amazing, despite the right image being a little blurry. It looked good enough that I went back and redid it in color. Still awesome. The handlebars and near pedal really jump out:



And finally I did this picture of my messy desk and bookshelf. It looks alright:



I think the first and third images both suffer from too much variation in depth. You can see that, e.g., the laptop screen in the first picture and the phone cord in the last one are way far apart from each other in the two channels, and when you look at them through the glasses those parts are not easily resolved into coherent objects without refocusing your eyes.

Now that I had more of an idea how to work with this stuff on the computer, I scanned in my original ink line art that I had traced for the 3D pencil drawing. I separated it into red and blue/green layers and then moved stuff around and the results are actually okay:



I plan to keep playing with this stuff...I definitely need some 3D cat photos, and I want to try the drawing kit with some better pencils.