Mask Obstructing Object Out

I have video of an object with a screen. But a piece of cloth is hanging in front of that screen.

I've tracked the object's screen via Mocha V2 (CS5).

Back in AE, the tracked screen lies on top of the cloth, and looks unnatural. Any ideas or tutorials on masking an obstructing object out?

I am stomped on something that really should be simple.

I can't post the actual image for confidentiality reasons, but it's like this (below).

Let's say I tracked this TV screen in Mocha. I drew my track box aroud the screen and the remote (as one).

Now in After Effects, I pasted that tracking data onto a solid layer. The solid with the tracking data fits over the screen of the TV as it should. BUT, the (tracked) screen appears OVER the remote control.

How do I get that tracked solid to hide under the remote control instead of lie over it?

I am happy to report the solution.

I created a track of the screen, then on a separate layer, rotoscoped the obstructing object.

I turned OFF the tracking for the obstructing object's layer, and only exported the screen's layer, applied it in AE, and that's all for part one.

To get the screen to lie behind the obstructing layer, I did the next step:

I returned to Mocha, selected the obstructing layer, and now exported shape data.

Back in AE, I pasted that shape data onto a solid, and with the tracked footage underneath, used that shape as an Alpha Inverted Matte.

It worked!!

I also purchased the Curious Turtle Rock Steady course on AE CS5/Mocha v2. Hopefully that'll help further.

http://www.imagineersystems.com/store/index.php?target=products&product_id=...

Sources: Lynda.com's "AE CS5 New Creative Techniques: mocha tutorial" lesson

Creating Motion Graphics chapter on track mattes

Hey Lillian, im facing the same problem ( trying to mask the foreground out ) and somehow it doesnt work. I spent hours trying everything and i dont know what i am doing wrong.

Heres what i did:

tracked a screen.. tracked a finger (thats gets in the foreground) .. exported screen tracking data (corner pin) and applied it to an image in AE and it works, the image appears on my screen. Now when i export the finger shape data and apply it to the image nothing happens. I also tried applying it to my footage video => same result. Finally i created a new solid, pasted the shape data to that solid and tried every matte option (alpha matte, inversed alpha matte etc.) but it still didnt work.

Could you please tell me what am i doing wrong? If i make a solid, does it have to be on top of my image and video footage? Or in the middle ? Which layer gets the shape data? Which layer has to be inversed alpha ?


Im thankful for every hint.


PS:I even copied the shape data and pasted it onto a full size image (just to see what happens) and nothing happened. I checked the attributes of my shape data effect (called Finger) and there are keyframes for every single attribute (Translation X, Scale, Rotation etc.) but there is no single keyframe for the "Shape data" attribute.. Is that the problem?

Yes, I saw that one. Thanks. It was almost what I needed, but it's a Final Cut tutorial, so by the end, I didn't know how to use the shape data in After Effects until I did some research on my own.

At the end of the day, my final solution was to use the new CS5 roto brush. That way, I could adjust my mask within the comp instead of roundtripping to Mocha.