• Adobe After Effects Expressions

  How to randomize timing for random scale expression

  Posted by Chris Cameron on August 24, 2016 at 1:09 pm

  Hi All,
  I found the below expression provided by Dan on a much older thread which worked like a charm. Now I would like to figure out how to specify a random frame range as opposed to the scale change happening at regular frame intervals. Thanks!

  frame = Math.round(time/thisComp.frameDuration);
seed = Math.floor(frame/3);
seedRandom(seed,true);
s = random(50,150);
[s,s]


  Chris Cameron replied 9 years, 8 months ago 2 Members · 4 Replies
• 4 Replies

• 

  Dan Ebberts

  August 24, 2016 at 1:27 pm

  Like this maybe:

  frame = Math.round(time/thisComp.frameDuration);
  seed = Math.floor(frame/3);
  seedRandom(seed,true);
  f = Math.floor(random(0,timeToFrames(thisComp.duration)));
  framesToTime(f)

  Dan
• 

  Chris Cameron

  August 24, 2016 at 2:49 pm

  Thanks Dan, unfortunately I can’t get that to work…

  This is the original expression I’m working with to change the scale every 15 frames:

  frame = Math.round(time/thisComp.frameDuration);
  seed = Math.floor(frame/15);
  seedRandom(seed,true);
  s = random(145,275);
  [s,s]

  Can you tell me exactly how I should be incorporating your added line? This is what I just tried, hoping that it would set the random range between 1 – 30:

  frame = Math.round(time/thisComp.frameDuration);
  seed = Math.floor(frame/30);
  seedRandom(seed,true);
  f = Math.floor(random(0,timeToFrames(thisComp.duration)));
  framesToTime(f)
  s = random(145,275);
  [s,s]
• 

  Dan Ebberts

  August 24, 2016 at 4:53 pm

  Something like this maybe:

  
minFrames = 1;
maxFrames = 30;
minScale = 145;
maxScale = 275;

  f = timeToFrames (inPoint);
  fCur = timeToFrames(time);
  n = 0;

  while (f <= fCur){
n++;
seedRandom(n, true);
durFrames = Math.floor(random(minFrames,maxFrames));
f += durFrames;
}
seedRandom(n,true);
s = random(minScale,maxScale);
[s,s]


  Dan
• 

  Chris Cameron

  August 26, 2016 at 2:15 am

  Thanks so much Dan! That worked beautifully.

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