• Adobe After Effects Expressions

  Random speed of time

  Posted by Ilya Sire on March 25, 2015 at 12:13 am

  Hi forum,

  i have this T = time*effect(“Speed”)(“Slider”) to apply to substr(0,T)
  but is it possible to make it random speed to T value? so it will make time slow/fast/slow randomly speed within slider range value?

  I read about this from https://www.motionscript.com/articles/speed-control.html this way more advance i hardly to understand.

  I hope someone can help.
  Thanks

  Jason Jantzen replied 9 years, 11 months ago 3 Members · 12 Replies
• 12 Replies

• 

  Ilya Sire

  March 25, 2015 at 2:09 pm

  is this possible to do? please…
• 

  Dan Ebberts

  March 25, 2015 at 4:35 pm

  >is this possible to do?

  Probably, but I really don’t understand your question…

  Dan
• 

  Ilya Sire

  March 26, 2015 at 3:07 am

  T = time;
  substr(0,T);

  how can i make T running randomly speed? so the letters come sometime fast or slow.

  i got this similar result from your solution but this using slider to control speed. How to convert it using speed min or max value?

  Thanks
  ilya

  slider = effect("rpm")("Slider");
accum = 0;
f = timeToFrames(inPoint);
while (f < timeToFrames()){
accum += slider.valueAtTime(framesToTime(f));
f++;
}
accum*thisComp.frameDuration*60 //60 what is that?
• 

  Dan Ebberts

  March 26, 2015 at 6:14 am

  Like this maybe?

  
tMin = .05;
tMax = .5;
t = inPoint;
n = 0;
seedRandom(index,true);
while (t < time){
t += random(tMin,tMax);
n++;
}
substr(0,n)


  Dan
• 

  Ilya Sire

  March 26, 2015 at 6:43 am

  Ah yes!! i cant write like this.
  Thank you!
• 

  Ilya Sire

  June 10, 2015 at 8:09 pm

  Hi Dan,

  How to use this random value to linear() time?

  Thanks
  Ilya
• 

  Dan Ebberts

  June 10, 2015 at 8:13 pm

  I’m not sure what you mean…

  Dan
• 

  Jason Jantzen

  June 1, 2016 at 7:18 pm

  Hey Dan, I’m trying to use this idea here to animate the offset of a Trim Path so that when I duplicate each instance of the path, they animate at random speeds, but putting this expression on the Offset parameter yields an error “Function substr is undefined.” Any idea how to make this work?

  Jason Jantzen
  vimeo.com/jasonj
• 

  Dan Ebberts

  June 1, 2016 at 7:31 pm

  >putting this expression on the Offset parameter yields an error “Function substr is undefined.

  This is a source text expression, so it’s probably completely unsuited to what you’re doing. How are you animating the trim paths now? What range of speeds are you looking for?

  Dan
• 

  Jason Jantzen

  June 1, 2016 at 7:46 pm

  I was using this to get a random offset value with the time value. I’d like to randomize the time value somewhere between 25-35. Thanks for taking a look, Dan!

  seedRandom(1,true);
random(0,360)+time*30;

  Jason Jantzen
  vimeo.com/jasonj

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