Averaging Keyframes of Tracked Camera

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  05 May 2013
Averaging Keyframes of Tracked Camera

Hi everyone,

I'm working with a 3D camera track that has a little too much bounce in the y-position channel. Does anyone know of any good methods for 'averaging' the keyframes in order to get a smoother move? Since the camera path is somewhat complex, it isn't as easy as keeping the first/last keyframes and deleting everything in the middle.

Thank you so much!
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Mark Walczak

http://vimeo.com/mdwalczak
 
  05 May 2013
There probably is a clever way to literally average the keyframes, but I don't know it.

What I've done in the past is either to

1. select and scale the naughty keyframes in the f-curve editor.

2. Clean the naughty keyframes by selectively deleting the odd ones.

3. Use some rigging to have the original camera drive another camera, but overriding the naughty keyframe track and replacing it with some other control.

4. Go back into tracking and smooth the track.

5. I haven't done this, but if you have AE, move the camera into there and use the smoother to clean the tracks.

Hope that helps,

W
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@WillMacNeil_VFX
 
  05 May 2013
Is it a short section of the scene? If so you might be able to caress it into place with keyframe scaling. You could also caress when you do the final comp with a 2d transform on Y but if it is severely out so will any the motion blur be exaggerated and look wrong exactly like someone has stabilised shaking handheld footage.

If you can re-track. This is the only guaranteed way of matching. Not sure why a tracker would be out on just Y unless there's noise in the solution. That can come from excessive motion blur or rolling shutter (or both noways) i.e hand-held and footsteps.

I wonder if it's rolling shutter you could warp your back plate to remove rolling shutter or warp your insert in comp.

Are you sure it's bounce and not just your motion blur out of phase? (Guessing, because we've all been there!)

Without seeing the shot and the scale of your problem it's difficult to give you more specific advice other than best guesses
 
  05 May 2013
You can try the TL's "clean tracks" and "simplify" commands. At minimum that should reduce the number of stray KFs.
 
  05 May 2013
I wrote a script for this a while back that might help, I'll try and dig it out later and upload if you reckon it might be useful.

Preview:
https://vimeo.com/42503836

- EDIT - forgot I posted a link to it in the Vimeo comments (so many scripts here I lose track sometimes )

Cheers,
Brian
 
  05 May 2013
Hi Brian....great!!
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Cinema 4D Studio MSA, Zbrush, CS6, 3DCoat, Moi
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  05 May 2013
Hey Holger, thanks! Hope it helps. On a related note there's also this one which is quite similar, if you haven't seen it before - https://vimeo.com/42471806

Heh, I decided the other day I need to put together a scripting reel to show all the stuff I've written over the last couple of years as I have a lot of stuff now for both C4D and Maya, many that haven't been seen yet

Cheers,
Brian
 
  05 May 2013
Originally Posted by Horganovski: Hey Holger, thanks! Hope it helps. On a related note there's also this one which is quite similar, if you haven't seen it before - https://vimeo.com/42471806

Heh, I decided the other day I need to put together a scripting reel to show all the stuff I've written over the last couple of years as I have a lot of stuff now for both C4D and Maya, many that haven't been seen yet

Cheers,
Brian


I love Scripting/TD Reels....go ahead.
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Cinema 4D Studio MSA, Zbrush, CS6, 3DCoat, Moi
Twitter: @holgerbiebrach
www.c4dStuff.com

HB_ModellingBundle
 
  05 May 2013
Thanks Holger.. it's in the works

Cheers,
Brian
 
  05 May 2013
This may be too far outside of the box...

In this file, I am using a Constraint tag to target the movement of the hyperactive camera as well as another camera keyframed to take the most direct path from A to B.

By adjusting the Tag weights, you can shift the degree to which your camera follows the bumpy ride, or the artificially smooth one.

https://dl.dropboxusercontent.com/u...hing_JW.c4d.zip

HTH
 
  05 May 2013
^ Another approach along those lines is to use animation layers and animate the blending, always multiple ways to achieve stuff. There's also Reduced modification mode in the timeline, FCurve snapshots etc which are pretty good for cleaning mocap manually.

Cheers,
Brian
 
  05 May 2013
I can remember working with tracking data that had been solved from a stabilised plate but we were given the unstabilised plate to comp onto as the director preferred the shakier footage. It was in the days when matchmoving was incredibly tedious and expensive and couldn't be redone in time.

We tracked our 3d onto the unstabilised plate in 2D and manually added fake motion blur, it worked better than it should've. The old trick of stabilise/destabilise in Shake served us well.

I'd give the 2D approach a whirl it's amazing how much you can get away with and at least it'll stick. Blending keyframes is all well and good but you don't need to be far out for things to swim. Given how poor C4D's viewport handles the background object You won't be able to see how the matchmove is without rendering out tests which takes time. In the compositor it'll be near realtime and as long as there's no swimming you can get away with murder.
 
  05 May 2013
Where did you get the tracked data? I would ask them to run a smoother pass from the original track software. For example in Synth Eyes, there are smoothing filters just for this. It also allows them to use that same smooth data to re-process the video itself to smooth it as well in sync with the smoothed data. If you smooth your data afterwards, unrelated to the video, you can get a result that looks pretty on it's own but is a train wreck when matched back with the original shot.
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chris smith :: sugartv
 
  05 May 2013
That's a lot of replies without any response from the OP. I wonder is this one of those hit-and-run threads.

Interesting signature BTW Antimatter. Seems like a good recommendation for C4D that it took 3 applications to replace it


Cheers,
Brian
 
  05 May 2013
Originally Posted by Horganovski: That's a lot of replies without any response from the OP. I wonder is this one of those hit-and-run threads.

Interesting signature BTW Antimatter. Seems like a good recommendation for C4D that it took 3 applications to replace it


Cheers,
Brian


Hit and run or a "oh shit my start frame was wrong."

Well, I like to think we're a more rounded studio now, I'm kicking myself for not getting Softimage sooner.

All the best.
 
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