• Adobe After Effects Expressions

  randomly loop keyframes – change to color

  Posted by Wouter Sel on September 6, 2012 at 8:43 am

  Hi, i want to randomly loop keyframes using an expression.
  I’ve made 4 hold keyframes in the Change to Color effect of a layer;
  so that’s 4 specific colors (not random) i want to cycle in a random order over time.

  I also want to be able to edit the speed of the color flickering.

  Pre-comping the layer for time-remapping is not really an option,
  since i have 100+ layers in the comp, and they all should flicker randomly between those 4 colors.

  Wouter Sel replied 13 years, 8 months ago 2 Members · 2 Replies
• 2 Replies

• 

  Dan Ebberts

  September 6, 2012 at 1:20 pm

  Something like this should pick a random keyframe value every half second:

  
period = .5;
seed = Math.floor((time-inPoint)/period);
seedRandom(seed,true);
if (numKeys > 0){
n = Math.floor(random(numKeys))+1;
key(n).value;
}else
value


  Dan
• 

  Wouter Sel

  September 6, 2012 at 1:31 pm

  Thanks for the reply Dan, I’ll give it a try!

  meanwhile I’ve found this after some digging, and it works great:

  posterizeTime(12); // value is in fps
r = Math.ceil(random(0,numKeys));
valueAtTime(key(r).time)

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