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SynthEyes and the Coordinate Measuring Machine
Pretend SynthEyes is a 2D-to-3D-converting black box on your desk that manufactures a little foam-core architectural model of the scene filmed by your shot. This little model even has a little camera on a track showing exactly where the original camera went, and for each tracker, a little golf pole and flag with the name of the tracker on it.
Obviously SynthEyes is a pretty nifty black box. One problem, though: the foam- core model is not in your computer yet. It fell out of the output hopper, and is currently sitting upside-down on your desk.
Fortunately, you have a nifty automatic coordinate measuring machine, with a little robot arm that can zip around measuring coordinates and putting them into your computer.
You open the front door of the coordinate measuring machine and see the inside looks like the inside of a math teacher’s microwave oven, with nice graph-paper coordinate grids on the inside of the door, bottom, top, and sides, and you can see through the glass sides if you look carefully. Those are the coordinates measured by the machine, and where things will show up at inside your animation package. The origin is smack in the middle of the machine.
So you think “Great”, casually throw your model, still upside-down, into the measuring machine, and push the big red button labeled “ Good enough!” The machine whirs to life and seconds later, your animation package is showing a great rendition of your scene—sitting cock-eyed upside down in the bottom of your workspace. That is not
what you wanted at all, but hey! That’s what you got just throwing your model into the measuring machine all upside down.
You open up the door, pull out your model, flip it over, put it back in, and close the door. Looking at the machine a little more carefully, you see a green button labeled “ Listen up” and push it. Inside, a hundred little feet march out a small door, crawl under the model, and lift it up from the bottom of the machine.
Since it is still pretty low, you shout “A little higher, please. ” The feet cringe a little—maybe the shouting wasn’t necessary—but the little feet lift your model a bit higher. That’s a good start, but now “ More to the right. Even some more.” You’re making progress, it looks like the model might wind up in a better place now. You try “ Spin around X” and sure enough the feet are pretty clever. After about ten minutes of this, though the model is starting to have its ground plane parallel to the bottom of the coordinate measuring machine, you’ve decided that the machine is really a much better listener than you are a talker, and you have learned why the red button is labeled “Good enough!” Giving up, you push it, and you quickly have the model in your computer, just like you had positioned it in the machine.
Hurrah! You’ve accomplished something, albeit tediously. This was an example of Manual Alignment: it is usually too slow and not too accurate, though it is perfectly feasible.
Perhaps you haven’t given the little feet enough credit.
Vowing to do better, you try something trickier: “Feet, move Tracker37 to the origin .” Sure enough, they are smarter than you thought.
As you savor this success, you notice the feet starting to twiddle their toes.
Apparently they are getting bored. This definitely seems to be the case, as they slowly start to push and spin your model around in all kinds of different directions.
All is not lost, though. It seems they have not forgotten what you told them, because Tracker37 is still at the origin the entire time, even as the rest of the model is moving and spinning enough to make a fish sea-sick. Because they are all pushing and pulling in different directions, the model is even pulsing bigger and smaller a bit like a jellyfish.
Hoping to put a stop to this madness, you bark “Put Tracker19 on the X axis. ” This catches the feet off guard, but once they calm down, they sort it out and push and pull Tracker19 onto the X axis.
The feet have done a good job, because they have managed to get Tracker19 into place without messing up Tracker37, which is still camped at the origin.
The feet still are not all on the same page yet, because the model is still getting pushed and pulled. Tracker37 is still on the origin, and Tracker19 is on the X axis, but the whole thing is pulsing bigger and smaller, with Tracker19 sliding along the axis.
This seems easy enough to fix: “Keep Tracker19 at X=20 on the X axis .” Sure enough, the pulsing stops, though the feet look a bit unhappy about it. [You could say
“Make Tracker23 and Tracker24 15 units apart with the same effect, but different overall size.]
Before you can blink twice, the feet have found some other trouble to get into: now your model is spinning around the X axis like a shish-kebab on a barbecue rotisserie. You’ve got to tell these guys everything!
As Tracker5 spins around near horizontal, you nail it shut: “ Keep Tracker5 on the XY ground plane.” The feet let it spin around one more time, and grudgingly bring your model into place. They have done everything you told them.
You push “Good enough” and this time it is really even better than good enough. The coordinate-measuring arm zips around, and now the SynthEyes-generated scene is sitting very accurately in your animation package, and it will be easy to work with.
Because the feet seemed to be a bit itchy, why not have some fun with them?
Tracker7 is also near the ground plane, near Tracker5, so why not “ Put Tracker7 on the XY ground plane.” Now you’ve already told them to put Tracker5 on the ground plane, so what will they do? The little feet shuffle the model back and forth a few times, but when they are done, the ground plane falls in between Tracker5 and Tracker7, which seems to make sense.
That was too easy, so now you add “Put Tracker9 at the origin .” Tracker37 is already supposed to be at the origin, and now Tracker9 is supposed to be there too? The two trackers are on opposite sides of the model! Now the feet seem to be getting very agitated. The feet run rapidly back and forth, bumping into each other. Eventually they get tired, and slow down somewhere in the middle, though they still shuffle around a bit.
As you watch, you see small tendrils of smoke starting to come out of the back of your coordinate measuring machine, and quickly you hit the Power button.
©2024 Boris FX, Inc. — UNOFFICIAL — Converted from original PDF.