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flagsdivide
05-31-2005, 09:15 AM
Hey all-

I just tracked a verticle pan in boujou and was not successful initially so I masked the subject which is down on the ground and retracked it and getting pretty good results now, however I noticed the subject shifts a little when I combine the footage with a CG ground.

The subject was shot on blue screen with some markers to help boujou track. The camera points towards the horizon and pans down to reveal the subject.

I don't know what else I can do to "lock" the subject to the ground. Please help. ty.

Maxim
05-31-2005, 10:03 AM
hi,

i think it is not uncommen to do a retracking on a 3d-track to really lock the layers.

i would try to stabilze the markers on the bluescreen element to have an unmoving layer. (of course you will still see the perspective change, but this is not a problem). then you track a point in your cg-element and bind your stabilized layer to it.
make sure that your tracking points are at nearly the same position to avoid perspective shifts.

in short form:
stabilize one layer and matchmove it to the other.

good luck

ps: when i think about it... it might be better to matchmove th cg-element to the bluescreen-element. in this case you keep your original grain and sharpness in the foreground and automaticly add a slight blur to the backgroud. often the cgi is too sharp so you have to blur it anyway.
but the theory of retracking is the same.

samulih
05-31-2005, 12:40 PM
I am not sure if there is a possibility to use helper frames in Boujou like in Match mover and Syntheyes (and propably in PFTrack), but using these "helper frames" with panning shot will help your tracker to recognize the placement of your tracker points in 3d space better and so they might give you a better result and more precise homegrid... I just made a tracking of a panning camera with Syntheyes using helper frames and it worked out just fine..

I think that if you use Boujou tracker that is at least 10 times more expensive than Syntheyes, there should be a possibility to use these helper frames.. check out the manual of Boujou and find with words "helper frames".

greets,
samulih

samulih
05-31-2005, 12:43 PM
And also.. use manual tracking! ;) and if you have someone acting in front of the bluescreen, mask the guy with garbage mask before tracking (even before tracking with automatic track) moving objects with tracked scene makes the tracker go wild sometimes..

greets,
samulih

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