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Author
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Topic: Motion Tracker
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movies_lover
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posted 04-09-1999 12:31 PM
Hi all,
How does the motion tracker work? how to plan for it? and what software should I use to superimpose the live moving background over the blue-screen shot live actors?
Is there a place on the web with these info so I can look up to find out more about this technique?
Thanks in advance. |
EricM
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posted 04-12-1999 05:56 PM
Motion tracking is pretty much what it sounds like, but here's an example.
Say you're Luke Skywalker and you want to practice your lightsaber techniques. If you want to know how to make a good lightsaber effect there's plenty of past posts that explain that. But what about the seeker ball? You're using a hand held camera that pans and tilts during the shot. You need to translate that camera motion into the seeker ball motion.
This is a job for motion tracking! The most basic tracking job is to pick a small area in the shot that has high conrast and does not leave the frame or get blocked out by anything else. The computer will track this point through the shot. Now you apply the camera move to the seeker ball motion. This will make it look like the seeker ball was shot with the same camera move as the background footage.
Motion tracking can get more complicated with 2 points (for position, rotation and scaling) or 4 points. There is also 3D motion tracking which is complicated and expensive.
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movies_lover
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posted 04-13-1999 12:16 AM
Thanks Eric for the useful info.
You said the word 'computer' involved in this technique, so do you know what software to use to do this kind of motion tracking?
Any other info would be greatly appreciated.
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EricM
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posted 04-13-1999 07:30 PM
The motion tracking I've done is on Flint form Discreet Logic. It's now called effect*, and I believe that the PC and Mac version also has motion tracking (oh yeah, paint* also has tracking), so does After Effects (PC/Mac), Commotion (Mac) and 3D Max (PC). |
