Looking for tracking help

Hello,

I have a shot that is giving me troubles. I tried it a while back, but didn’t get a good solution, so I shelved it. I’m now trying it again with a newer version of Mochoa (v1.2.0).

Take a look at the attached pdf for some sample frames.

As you will see the track holds from frame f1-103. At f104 it loses the track and I just can’t get it back after the van passes by the trolly. I started the tracking at f90. I just can’t figure out the proper steps to regain the track after the van passes. All manner of twiddling with keys after the van have been futile. The attached pics show the situation AFTER the initial tracking, and NOT after my key adjusting when the track is lost. I have tried many different spline shape options, and the current shapes have given the best results.

Any pointers would be appreciated.
Thanks,
-David

Hmm that one is a puzzle indeed. When the van passes by, it pretty much obscures the entire trolly - and what IS left has no useful reference points (with all those horizontal stripes…) The windows are a bust because you can see inside the trolly too much so that data becomes mostly bogus to the tracker.

What exactly are you trying to replace? Just the billboard on the side (the white Calvin sign)?

If so, the path of least resistance – and what I’d probably do myself – is to treat the shot as 2 separate pieces, instead of trying to get a single track for the entire shot. Don’t make it any harder than it needs to be.

Do one layer for the front of the shot until the van obscures the right edge of the sign (frame ~105). Then pick it back up a few frames later at ~110, with a totally new layer, and keyframe your search shape for a few frames to continue to encompass more and more the side of the trolly as revealed by the back of the van.

There might be a couple of keys you’ll have to fudge manually on either side.

Here’s a quick test using the method I described - not trying to track the entire shot but treating it as two totally separate setups.

Bad comp done in AE…

http://burner.com/TrollyTestComp.mov

One thing I did first was to re-render the image sequence brightening it up a lot to reveal some detail to me to figure out where to track - it might have helped Monet too.

In Monet, first I hand-animated a shape layer around the van from about frames 87 to 176 so that it could be ignored by the tracker. Note that this layer needs to be IN FRONT OF/ABOVE the other two main ‘tracking layers’.

Next I did the front part of the track, drawing 3 shapes (see attached ‘fronthalf.jpg’). I drew them starting at around frame 87 and then tracked backwards to the head of the shot. Make sure to turn ‘Selected layers’ on in the Track menu, not ‘All’, so it doesn’t try to track the van and go nutty.

Next I did the back half of the track, on a new layer, drawing 2 shapes starting at frame 110 (see attached ‘backhalf.jpg’). Note that the screengrab is taken further down the shot to show what it wound up encompassing after the van passed; I originally drew it shorter and stopped a few times during the track to reshape it/make it longer and bigger as I saw fit.

Lastly exported AE cornerpin keys and whacked up the composite in AE, manually animating a mask around the van to put it back over my replaced sign.

I didn’t take the shot any further than when the billboard starts to hit the car and didn’t mask that.

Oh an by the way I imported the footage as 24fps which is probably wrong (looks a little slow) but nevermind that :rolleyes:

Hi Ross,

I finally found time to get back to Mocha and this shot. I still have not gotten it nailed yet. I guess I’m still looking for some help and methodology on how to approach a shot like this in Mocha.

I have put the project up on my web site, if you have time to download and look at it for me. I jpeg’d the source files to get them a bit smaller, but the download is still about 80MB or so.

I hope you can give it a shot as I’d like to get a feel for how to work better in Mocha. By the way, the last few tutorials that imagineer have posted are very helpful. Thanks and I hope to see more in the future as I still feel Mocha is a bit under-documented.

Go here for the files:
Download project and source files (http://www.digitalrenaissance.biz/uploads/public/Source.rar)

PS. Files are uploading now, it will take a few minutes…

TIA,
-David

Hello Bob and Ross,

Sorry for my late reply to your posts, but the board auto emails ended up in my SPAM and I missed your replies.

Thanks for taking a look at this for me. Your help should push me in the right direction to finish this shot, I appreciate the time you took looking at my issue.

Cheers!
-David

Hi Ross,

I started reworking the shot using a spline on almost the entire side of bus, with the cutout splines for the windows as you suggested. Along with splines on all the passing cars and the sign pole, and that got me to frame 152 in one pass. That is almost the entire time the trolly is in frame. I just need to get a few more frames tracked at the end now.

Using the entire side of trolly, with the negative shapes is really a good solution. I must keep this in mind for the future. I think I can now put signs on the entire side of trolly by duping the layer and redoing the surface cornering pinning. I guess in theory I could replace the windows if I wanted to try that (not easy to create the elements).

I’m learning more about Mocha on this project.

Perhaps if I can clear it with the owner of the footage, I might try to put together a short tutorial and give back a bit of what I have learned here. We’ll see about that.

Thanks again,
-David

PS. I have a quick slap comp out of Fusion 5.3 to test the tracking:
http://digitalrenaissance.biz/uploads/public/Test1.trolly.mov (http://Test movie HERE)

There are a couple ways to nail this:

One might be to add a more shapes to the layer. Try one shape for the entire side of the bus including windows and then some subtract shapes for the interior of the windows. It needs more to track when the van is in front.

Another solution woul dbe to manually track when the van is in front and use adjust track module and offset refs to nail the positioning.

If you want to email or post me the clip, I could take a look.

Best,
Ross

Hey there,
I finally looked at this… I was able to get a pretty good result by making 1 large shape around the most of the side of bus, than subtracting the windows with smaller shapes within that layer. You definetly need to avoid the reflactions, but I found with a few tests that the edges of the windows actually give you something to lock onto when most of the sign is obscurred.

Either way, this is a great shot for adjust track, as you really need to use the tool to compensate for some drift and when the bus is obscured.

I hope this helps and as Bob mentioned, sometime it helps to break up a shot into 2 separate tracks.

Another tip can be to select manual track which exposes the track keyframes. Than you can delete and or manually edit the tracking data similar to how you would have to deal with it in most tracking applications. :slight_smile:

Best,
Ross

—Quote (Originally by drswoboda)—
Hi Ross,

I finally found time to get back to Mocha and this shot. I still have not gotten it nailed yet. I guess I’m still looking for some help and methodology on how to approach a shot like this in Mocha.

I have put the project up on my web site, if you have time to download and look at it for me. I jpeg’d the source files to get them a bit smaller, but the download is still about 80MB or so.

I hope you can give it a shot as I’d like to get a feel for how to work better in Mocha. By the way, the last few tutorials that imagineer have posted are very helpful. Thanks and I hope to see more in the future as I still feel Mocha is a bit under-documented.

Go here for the files:
Download project and source files (http://www.digitalrenaissance.biz/uploads/public/Source.rar)

PS. Files are uploading now, it will take a few minutes…

TIA,
-David
—End Quote—

No problem,
Let us know how it goes! Its a good challenging shot and I’m quite sure that mocha will save you a lot of time versus a point tracker…

-Ross

—Quote (Originally by drswoboda)—
Hello Bob and Ross,

Sorry for my late reply to your posts, but the board auto emails ended up in my SPAM and I missed your replies.

Thanks for taking a look at this for me. Your help should push me in the right direction to finish this shot, I appreciate the time you took looking at my issue.

Cheers!
-David
—End Quote—