I have two white shapes that overlap on a purple background, which are in a pre-comp. One in animated (an arm) and the other is not (the rest of the body).

When I fade the pre-comp in, from 0 to 100 opacity, I can see the parts where the shape overlaps. This is made worse by having a motion blur, which seems to multiply the blur in that area.

enter image description here

Do you know how to avoid this situation, and to have the two shapes behave as one.

  • Are you fading in the parts of the pre-comp or are you actually using the pre-comp in another composition and fading in the entire pre-comp? This appears to be the result of a blending issue since if you aren't using a separate comp, you end up with two objects being blended at 50% but behind one object at 50% is another object at 50% which blocks out more than 50% of the background, thus you see the difference.
    – AJ Henderson
    Commented Oct 13, 2014 at 14:04
  • The body and arm are two shapes in a pre-comp. Then the pre-comp itself has the opacity change animation on it. Commented Oct 13, 2014 at 14:21
  • Hmm, no idea then. The issue is definitely blending related, but I'm not sure the best way to fix. It is treating it as 2 50% solids instead of 1 combined solid that is at 50%.
    – AJ Henderson
    Commented Oct 13, 2014 at 14:35

1 Answer 1


Pretty sure this is due to the little sun icon - the "collapse transformations" icon.. See more here: http://helpx.adobe.com/after-effects/using/3d-layers.html

It's to do with what order 3D comp layers are processed when they're precomped.

  • Yes, that worked thank you. I wrapped the pre-comp inside another pre-comp and collapsed transformations on the top two layers of pre-comp. People (waving animation) > People Wrap (Nothing going on here) > Icon People (Collapse transformations) > Main Comp (Collapse transformations). Commented Oct 14, 2014 at 13:10

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