Layered tracking for hidden objects

Mocha AE
#1

Hi there,

yesterday I got awesome support here. To be honest, I had to done much more research but then I got a very clean and professional looking track.

So, maybe the topic title is not to clear in fact of what I want to achieve.

I’ve a hand coming into the shot - touching a stone (very fast - like the hand is beeing pulled from the the logo which I want to attach to the stone)

I have understand to create 2 “shapes” - but unfortunately it seems like the hand is “to big”. What I mean is that the track of the stone (where I want to attach the logo) is drifting - no matter what I do.

The other thing is - I think I have to do rotoscoping as I want the logo to be hidden when the hand touches the stone.

To be honest I am really confused - I do not know how to handle in which order. Furthermore I cant adjust the track as I do not have a real square or something else:

image1
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image2
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Could anyone help me out?

Thanks in advance

#2

First up, you’re going to need to clip the frame. The black letterboxing is going to interfere with the track.
Go to the “Clip” module tab and choose the clip mask, the drag the yellow box edges to cover the inside edge of the letter boxing.
When you switch back to “track” the clip will be shown without the black lines.

That should stop most of the drift when you track.

For the hand, compositing it back on top is going to required very tight roto and motion blur or feathering. If the fingers are moving as fast as you say they are, then the fall-off of the motion blur is going to be quite high and you’ll get bleed of the stone underneath.

Try getting to core solid parts of the hand and fingers done first though. I recommend breaking it up into parts rather than using a single shape.

#3

Hi martinb,

thanks for your reply. I did the clip mask thing and made more single shapes to the Hand/Arm. I have set these layer option to “substract”

Anyway, the problem is the same. The place where I want to display the logo is still drifting like hell:

I have watched tons of tutorial and I rly cant find out what I am doing wrong.

#4

You probably need to update your versions, there is an old bug where top shapes don’t hold out like they should in older versions of Mocha.

Try just not tracking where the hand is, there’s plenty of texture to track to the side of the hand, just move the surface tool where you want the logo to be.

Try that and let us know? Sorry for the delay, I was out for two weeks and we were short staffed on the forums.

Cheers,
Mary