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Improving 3D Camera Tracker Count?

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Max Jackson
Improving 3D Camera Tracker Count?
on Nov 6, 2012 at 3:38:38 am

Hi CC,

I'm working on a shot that doesn't have a whole lot of light and I needs to track a few point on a woman's face looking around.

I've done numerous pre-renders pushing contrast and I'm not getting anywhere.

Is there a good technique to amplify marker count in low-key shots?


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Vishesh Arora
Re: Improving 3D Tracker Count?
on Nov 6, 2012 at 6:11:35 am

Max

If Ae tracker is not working fine, then Go to Animation>Track in mocha AE.

Mocha is much powerful then AE defaults tracker. You can directly import the tracking data into AE.

Tutorial for mocha:






Vishesh Arora
3D and Motion Graphics Artist
Films Rajendra

Blog:
http://digieffects.wordpress.com

Demo Reel(3D):







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Angelo Lorenzo
Re: Improving 3D Tracker Count?
on Nov 6, 2012 at 7:24:27 am

I agree with Vishesh, sounds like you want to check out Mocha. At the least, Mocha's tools are more robust when it comes to manually correcting a motion track than AE's built in point tracker.

Angelo Lorenzo
Fallen Empire Digital Production Services - Los Angeles
RED transcoding, on-set DIT, and RED Epic rental services
Fallen Empire - The Blog
A blog dedicated to filmmaking, the RED workflow, and DIT tips and tricks


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Max Jackson
Re: Improving 3D Tracker Count?
on Nov 6, 2012 at 7:30:52 am

Hi Vishesh/Angelo,

I'm actually referring to the 3D Camera Tracker in CS6, not the old school native 2D Motion Tracker.

Good call though.

Thanks!
-m


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Roland R. Kahlenberg
Re: Improving 3D Tracker Count?
on Nov 6, 2012 at 12:26:32 pm

AE's 3D Camera Tracker doesn't track moving animating objects. Your best bets are a dedicated 3D matchmover and a long learning curve or mochaAE/mochaPro 3.1.

mochaAE/mochaPro 3.1 includes a camera solve module which also supports 3D object tracking. Here's a test -



I did a short while ago.

Here's a full-fledged tutorial by mocha's Product Manager, Martin Brennand on 3D object tracking -

HTH
RoRK

Intensive mocha & AE Training in Singapore and Other Dangerous Locations

Imagineer Systems (mocha) Certified Instructor
& Adobe After Effects ACE/ACI (version 7)


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Max Jackson
Re: Improving 3D Tracker Count?
on Nov 6, 2012 at 6:17:08 pm

The sample you posted is awesome! That's just what I'm looking for.

Well, the bummer is I only have the trial version of CS6 which apparently doesn't come with Mocha 3.1 cuz I don't see it anywhere.

So I'm pretty much stuck with AE's Camera Tracker or Mocha 2.2.

I've seen tutorials online where AE's Camera Tracker follows objects in motion. My major reason I'm trying to use AE's Camera Tracker is because I'm dealing unfortunately dealing with rotation and I need something as sensitive to that as possible. AE's Camera Tracker from what I've seen online seems to handle these angles well with text.

So is there a way to improve my overall track point count?


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Shawn Miller
Re: Improving 3D Tracker Count?
on Nov 6, 2012 at 7:02:09 pm

It might be helpful to see a clip or a frame grab from the footage in question. :-)

Shawn



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Max Jackson
Re: Improving 3D Tracker Count?
on Nov 6, 2012 at 7:16:21 pm

Sure thing Shawn,

I've got her head and hand rotating. We can try to edit with cutaways but that is the principle action taking place. My average pixel error is over 4 pixels. Even if this is the wrong tool to try and use, I'd like to know why I'm not using it properly or why I can't seem to get any decent tracking points out of this scene.

Essentially I'm trying to put 'goo' on her face and have it track along.

In any case, thanks everybody for responding.

Attached are a couple screen grabs to display the idea in motion.





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Shawn Miller
Re: Improving 3D Tracker Count?
on Nov 6, 2012 at 8:29:31 pm

[Max Jackson] "My average pixel error is over 4 pixels. Even if this is the wrong tool to try and use, I'd like to know why I'm not using it properly or why I can't seem to get any decent tracking points out of this scene."

Hi Max,

I think the biggest issue here is that you don't have enough 'good' features on the face for a solid object track. Usually, you would want a variety of high contrast features distributed along the surface of the object you want to track. Otherwise, the software can't tell the difference between something that is on the side of an object as opposed to something that is on the front of it. That's why we usually put markers on the face of the talent for shots like this.

As Roland points out, the AE Camera Tracker doesn't do object tracking. IMO, your best bet to complete this shot is to go back, practice the effect then re-shoot it if you can. If you're interested in doing more effects like this, you might want to consider picking up Tim Dobbert's excellent book "Matchmoving: The Invisible Art of Camera Tracking". It covers in good detail most of the things you need to understand, in order to get these kinds of shots up and going. There are also a ton of "head tracking" tutorials out there, most are okay, but you can get a pretty solid idea of how the more successful shots are setup just by watching them.

Thanks,

Shawn



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Max Jackson
Re: Improving 3D Tracker Count?
on Nov 6, 2012 at 8:43:20 pm

Hi Shawn,

Thanks a bunch for taking time to explain the difference. I don't completely follow but like all things that comes with time and practice.

That shot was done on my very first day on the job. I told them they should really use greenscreen for isolation but the DP was worried about spill. I wanted to tell her that we could adjust that but...didn't want to start bossing people around. Heh, anyway I don't think we can get that shot again. If we can, I'll definitely ask the director to get ample light for value referencing and add points that we can brush out for tracking.

I'll also definitely pick up that book as 3D tracking/rigging looks like something I'm going to be involved with one way or another. I'll keep watching online.

Thanks!


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Roland R. Kahlenberg
Re: Improving 3D Tracker Count?
on Nov 7, 2012 at 2:00:15 pm

Hi Max, it looks like you're trying to accomplish a perspective track of a face. This should be doable with the version of mocha (2.6.2) that ships with AE CS6. In CS6, you access mochaAE by selecting Track in mochaAE, which is accessible via the Animation menu.

Of course only mochaAE V3 and mochaPro V3 provides camera solves with mochaPro providing other high-end visualFX modules and tracking/shape export options.

I suggest that have a look at the following tutorial - http://provideocoalition.com/index.php/motiongraphicsvizfx/story/face_repla... to get an idea of how to track a face. The only issue I see you having are the moving shadows in your shot. The movement will of course mislead the tracking algorithm as to what it should be tracking. You'll have to study the clip carefully before deciding which area to track.

HTH
RoRK

Intensive mocha & AE Training in Singapore and Other Dangerous Locations

Imagineer Systems (mocha) Certified Instructor
& Adobe After Effects ACE/ACI (version 7)


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