animating masks
by Matt Masi
on
Jan 5, 2008 at 5:01:25 pm
Hi all,
I'm very much an After Effects newbie, so I apologize if what I'm asking is very basic.
I have two video clips that I'm trying to create a picture within picture effect with. Using a mask, I've selected the portion of the second clip I want to show up in the first. I am able to move the mask's position anywhere I want in the Composition window.
What I want to do is begin with the second clip completely filling the screen, and then at a certain point I want the mask to be activated so that the first clip is exposed, creating the picture-in-picture effect. Right after this happens, I want the mask's position to move to a different part of the screen using animation, where it will stay for the remainder of the presentation.
I've accomplished the picture-in-picture effect using the mask, but animating the mask is where I'm running into the problem. Where I want the animation to begin, I click the stopwatch next to Mask Path. Then I move the scrubber to the point I want it to end. However, when I try to move the mask in the layer window to the desired position, instead of the entire clip moving with the mask (which is what I want), only the mask moves, revealing another part of the clip.
In the Composition window, when I move the mask it moves with the whole clip, which is what I want. But when you are animating with key frames, you have to change the position of the object in the layer window, and it's not working there.
For a specific example of what I mean, this video shows exactly what I am trying to accomplish. It involves two separate clips showing someone playing the game Rock Band. One clip focuses on the game screen while the other focuses on the drummer. It begins showing only the game screen, and then at about the :06 mark the drummer is revealed with and the game screen mask moves over so we can see him.
Like I explained above, I am having difficulty getting the game screen to move. Any help would be appreciated! BTW, I am using After Effects CS3.
Re: animating masks by Mike Clasby on Jan 5, 2008 at 8:07:58 pm
I'm not see the example as you explained, but if you're just trying to move the picture within the picture to a new position, try this:
Mask off the picture within the picture (the smaller screen) on the layer Above the main screen layer. It should appear as a cutout box above/on top of the main screen. Change it position with position keyframe.
