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motion Tracking help
I have a scene that I have been struggling with on some motion tracking. I have been using After Effects 7 pro, and shake 4 to composite multiple scenes for a 16mm film. The scene that I am struggling with deals with an infinite field of roses. The scene was shot against blue screen, and has a very tricky jib arm manuver that has to be tracked. The field of roses must be extended on the Z -axis and appear as if it is infinite in size. I have had much success tracking the other (more stable) scenes by using shake to match the camera moves. In the more complicated scene( having such a drastic change in camera perspective) the jib move looses the reference point with the tracker. I have not attempted an auto tracker in after effects, and have just ended up tracking this shot manualy. The manual track is still a little sloppy and shows show stuttering and shifting of the extended sections of the field. I could use some pointers on this. Any help would be greatly appreciated with speeding up this frame by frame process.
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4 Replies
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Hey, I just finished shooting my first 16mm film yesterday! Thought that was cool that you are using the same medium. Well, for motion tracking, a quick search of this site for those very words should yield a lot of helpful results. I used motion tracking in AE 7 for the first time last week and it is amazing! Fast too! It tracks almost in real time, so it should be a bit faster than your manual tracking.
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First up, maybe try degraining in AE first (16mm grain can be a bitch for getting a decent tracking lock without jitter). The other thing to do is to track forward, then backward (the same feature) and average them together (again to smooth the final track, ….you can indeed track multiple points and average them all).
Depending on how extreme the perspective change (camera move) is, you might actually need to do a 3d matchmove (track in matchmove software such as Boujou, Matchmover pro or Syntheyes). This will all you to solve for where the camera is moving in 3d space, then you can bring that into AE (using its 3d camera, …imported via .ma support) or Shakes multiplane node (personally I tend to have less grief with AE’s pseudo 3d than Shakes). Place additional layers on layers distributed through z space (i.e. layers switched to be 3d), and arrange them in the comp. You can get a really nice look if care is taken (as the parallax created adds to the reality of the shot). I use Syntheyes and Boujou with AE usually (and it has saved my butt on some pretty nasty tracks from time to time).
If you have Maya or 3d Max, head over to RealViz as they are currently offering their MMTrack plugin for free (its based on their matchmover pro 4 software but works within either Max or Maya). It doesn’t have all the features of a full blown matchmover application, but its still pretty good (and excellent for free!). Only other downside is it won’t export to external applications (although within maya you could probably export the camera solve to its native .ma format and import into AE or Shake).
Goodluck,
andrew
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thanks for the heads up on mmtrack
i went to the realviz site, an di see the trial version, but i dont see a free version.whered you see it was free?
thanks
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Can you post two or three frames anywhere for review?
FWIW:
Boujou and matchmover pro are what I usually use for handling 3D tracks. Depends on number of markers avaiable and the move. Boujou tends to be better at auto tracking, but when it fails it can be a bit challenging to coax a good track out of it …. meanwhile, matchmover pro is awesome at manual tracking with as litte as 7 markers (or even 4 if you have good survey data).I could be wrong, but I think “free” version of mmtrack has since become a “free demo” version of mmtrack.
Good luck.
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