• Adobe After Effects Expressions

  Random light intensity between two values

  Posted by Paul Trunkfield on October 29, 2009 at 12:56 pm

  Hi all,
  I have a scene set up where i have a 3d light randomly flickering on the subject. I have used the “Let there be light” expression from https://www.motionscript.com.

  segMin = 1.0; //minimum segment duration
  segMax = 1.5; //maximum segment duration
  flickerDurMin = .5;
  flickerDurMax = .8;

  end = 0;
  j = 0;
  while ( time >= end){
  j += 1;
  seedRandom(j,true);
  start = end;
  end += random(segMin,segMax);
  }
  flickerDur = random(flickerDurMin,flickerDurMax);
  if (time > end – flickerDur){
  seedRandom(1,false);
  random(100);
  }else{
  100
  }

  I would like to be able to set the random light intensity between two specific amounts such as 80% and 100% intensity.

  I don’t know much about expressions so any help would be really appreciated.

  Paul Trunkfield replied 16 years, 6 months ago 2 Members · 2 Replies
• 2 Replies

• 

  Kevin Camp

  October 29, 2009 at 5:13 pm

  just change the random value line where it says:

  random(100)
  
  to

  random(80,100)

  in the first expression, random(100), the zero is implied, so it really is saying random(0,100), changing that 0 to 80 sets the range to choose random numbers from to be between 80-100.

  Kevin Camp
  Senior Designer
  KCPQ, KMYQ & KRCW
• 

  Paul Trunkfield

  October 29, 2009 at 6:21 pm

  Brilliant – thanks very much for your help. Works perfectly.

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