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View Full Version : Matchmoving a problem shot -- possible solutions!

Jaist
01-29-2007, 11:52 AM
First i'd like to say hello to all of you people, it's been a while since i started lurking here and it's been a great resource until now. So kudos to everyone.

On to the task at hand now.
I work in a studio that has boujou three as their main tracking app. I've a background in pftrack and continue working with it, but i paired it with boujou to get the best results i can.

We were awarded with some difficult shot to work on, mainly greenscreen stuff with trackers.
Naturally i couldn't get a good first solve of the camera, so i manually tracked the points and then added some auto features on some stuff that showed parallax. Only the parallax stuff is at the beginning and the end of the sequence, with the middle section filled with a closeup of the main actor with barely two trackers showing up.
The movement of the camera on set was a diagonal dolly (facing the actors, starting at not-so-far-left and ending at not-so-near-right) with some panning and tilting of the camera, so i pretended that to be free motion.
Two days later i haven't been able to get a good result after frame 150 :banghead: , and there's 400 of them... any advices? there's always the handtracing method, but id' rather not do that since i have to comp other stuff... Keep in mind that i'm a mainly a compositor and not a matchmover (doing both of em since a year ago), so any advices (even the easiest one) is welcome.

Also, we can use this thread to share techniques about matchmoving since i haven't been able to find one while searching here (i could be wrong tho). It's not fancy stuff like modeling dragons and cute actresses but it's where part of the magic of a shot born ^_^

Thanks again for reading and let's get this thread rolling! :thumbsup:

Max
Jaist
01-31-2007, 05:58 PM
ok, here's a little reply to myself to keep you posted about the progress.

I've managed to get a pretty nasty solve from syntheyes, since PFtrack, BoujouThree and Matchmover pro (tryout unfortunately) couldn't get any track done at all (PFtrack performed better tho).

Did that with a try-and-learn hack: i hand tracked all the markers, often creating paths frame by frame when they were obscured by the actors.
Then i forced lock point constraints on every manual track i got from the greenscreen trackers (i had very rough measurements from the set) and i had syntheyes auto solve that.
Then i roughly recreated the camera translation movement (it was a dolly) in the top viewport, animating from start to end. Then i ran a solve on the path on top of the previous solution, aborted the solve after about 2/3 of the shot to avoid too much garbage, and finally got something barely manageable. :eek:

Then it was one day full of keys in maya, getting the fcurves smooth and correcting the inconsistencies (the 4 seconds in the middle section without many tracks were completely wrong). Then i reoriented the whole scene to the default coordinate system, to give the modelers a good start.

Damn hard i'd say, and the funny thing is that 11.000$ worth of apps weren't able to deliver what a 400$ app did.

Ok then, naturally this is by no means a production workflow, but sometimes hacks can be handy :thumbsup:

Share your thoughts, they are food for my brain ^_^

Max
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01-31-2007, 05:58 PM
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