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Forums Adobe After Effects Expressions Triggering Animation with Comments.

  • Triggering Animation with Comments.

  • Jon Wooley

    August 28, 2012 at 6:21 pm

    [Posted this in the main AE forum and received no response, hoping for better luck here, sorry if it’s too basic]

    Ok, so I do a lot of overlays for pre-recorded events and I was wondering if it was possible to trigger animations by using comments. Not in the Dan Ebbert way (, which I’ve used and love) but rather in a way that takes place within the same sequence using established values.

    Basically is there any way in AE to say, “Look at marker comment x. When comment x = Move45, take the curent rotation value of layer y and add 45 to it over the next 20 frames.”

    Is that even possible and what would be the best way of telling AE this?

    Thank you all in advance.

  • Dan Fredley

    August 28, 2012 at 7:01 pm

    Try this:
    //user-defined values
    durInFrames = 20;
    txt = 'Move45';
    addValue = 45;

    //AE-calculated values
    m = marker.nearestKey(time);
    str = m.comment;

    if(str === txt && m.time <= time) {
    start = m.time;
    end = m.time + durInFrames*thisComp.frameDuration;
    startValue = value;
    endValue = value + addValue;
    ease(time, start, end, startValue, endValue);
    } else {

  • Dan Ebberts

    August 28, 2012 at 7:32 pm

    Note that if you wanted to execute a sequence of commands, since expressions have no memory, you’d have to have your expression loop through all previous markers and add up all the previous commands to get the current value.


  • Jon Wooley

    October 2, 2012 at 1:55 am

    Perfect! Thank you both!

    And Mr. Ebberts, thank you for everything you’ve posted to date, your knowledge has been instrumental to me leaning expressions in AE.

  • Aaron Kent

    March 2, 2013 at 9:46 pm

    Would it be possible to see an example of looping through all the previous values in this expression so that the rotation continues to increment instead of snapping back?



  • Jon Wooley

    May 1, 2013 at 9:23 pm

    I’m not good enough to answer your question fully, but this page from Dan Ebberts’s site might help:

  • Aaron Kent

    May 1, 2013 at 9:29 pm

    Jon, I played around with that for a while. Lotta fun sequencing stuff:



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