Tracking a green screen with Mocha

[Roland R. kahlenberg]

Here are a couple of relevant mocha tutorials –
Tracking with Foreground Occlusion (TIME – 16:00 to 44:35)
https://vimeo.com/22899888

Tracking with Foreground Occlusion
https://vimeo.com/8057500

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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[Steven Probets]

Thanks guys! Very helpful.

I am basically putting an image on a phone screen in Mocha and AFX.

The phone is off screen then on screen. I am having trouble tracking this and then putting a surface on it. When the movement is going off screen my surface gets very ‘skewed wiff’.

I tried this tracking tutorial https://forums.creativecow.net/readpost/2/1017437 but it seems the object was tracked off screen automatically. As the phone has motion blur on it mine has not worked like this. Any ideas to track motion objects off screen to ensure the surface is always at the correct angles etc?

Cheers again

[Steven Probets]

Actually, I think I need to create a tracking area and then possibly key frame the last few frames myself (when the phone goes off screen) but make sure all the points are as they were when the phone is on screen, and just move/rotate them all together?…

[Roland R. kahlenberg]

In an ideal situation you would provide your footage so that folks can see exactly what’s involved. mocha’s tracking engine handles motion blur reasonably well – it all depends on how much motion blur there is and your search parameters in mocha.

As a general rule, when dealing with tracking objects that leave the screen (or get obscured by foreground objects), you have the following options –
1) increase the size of your tracking spline to cover more co-planar area
2) add an additional tracking spline onto a co-planar area
3) move the existing tracking spline onto a co-planar area
4) leave everything as it is and hope no one notices
5) use mocha’s adjust track module to fill in the ‘tracking data for the missing’ frames
6) make the adjustments manually in AE

So … lots of options for you. YOu should ensure that you export out corner pin data with motion blur (MB) support. In AE, set your comp’s MB setting such that Shutter Phase is -1/2 of Shutter Angle – this helps to mimic normal camera settings thus ensuring that your MB is centered on your object. Wrong MB settings will screw up the alignment of your corner pin alignment.

HTH
RoRK

Intensive mocha & AE Training in Singapore and Other Dangerous Locations

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