• Adobe After Effects Expressions

  Move an animated mask?

  Posted by Chris Heuer on September 17, 2008 at 2:18 am

  Hello my code heros! I have an issue that I think an expression will solve. I’m close but not sure of how to convert values.

  I am using the Reshape effect to move (warp) people, in a scene, a few pixels to the left or right. Reshape uses 2 or more masks from the same layer it is applied to. Since I have over 30 shots, I did the roto in Mocha and brought that matte into AE as a QT movie.

  I then used Auto Trace on the matte layer to generate a rotomask in AE. All I need to do now is duplicate the autotrace mask and slide the duplicate masks position to the left or the right a few pixels while retaining all of the existing animation. To simplify, I would end up with 2 identical animated masks that are (oh, let’s say) 10 pixels apart.

  I can’t get this to work by just highlighting all keyframes and dragging so I’ve tried basic pickwhip expressions. The property values of between “Mask Shape” and “Position” on a null don’t match up.

  Can you create an Expression Control (like a slider) that I can use to reposition a mask AND that doesn’t effect the masks current keyframed animation?

  Hope this makes sense. I think it’s not that hard but me no speak this level of expression!

  Thanks, Chris

  Chris Heuer
  Freefall FX, LLC

  Chris Heuer replied 17 years, 7 months ago 1 Member · 0 Replies
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