5 Replies Latest reply on Sep 15, 2010 2:15 PM by CrunchyTheClown

    How to customize Auto-trace selection over multiple frames?


      Hi all,


      I'm working on an After Effects CS5 project that involves a lot of compositing and my material is all in high-contrast black and white. I'm looking for a way to mask individual parts of a particular clip: e.g. I have a 10 second clip with two people standing in it, one on the right and one on the left. I'd like to isolate the person on the right and hide everything else, including the background and person on the left.


      I used Auto-trace to quickly find the outlines of my image and it works great since my picture is such high-contrast. Only thing is, I'm not sure how to remove the person on the left from the auto-trace selection.


      I have "work area" selected in my Auto-trace options, which is amazing as it makes the Auto-trace selection span over my entire 10 second clip (as opposed to me needing to apply it frame-by-frame), but now the problem lies in removing person on the left from the entire 10 second clip. I went to the beginning of the new layer (I have the "Apply to new layer" box checked in my Auto-trace options), used the "Delete Vertex Tool" (the pen tool with a minus sign on it), and removed the selection of the person on the left, but the selection exists in all the frames following it (i.e. 9 seconds and 29 frames), and only gets removed from the particular frame I was working on.


      Is there any way to get AE to remove the selection over the span of the clip as opposed to only the individual frame I'm working on?


      BTW, I'm not married to this method. If anyone has a better method I could use, I'm all ears, although I would like to see this through if possible.


      Any help is much appreciated!