• Adobe After Effects Expressions

  Increasing and decreasing opacity based on growing number from 0-1

  Posted by John Toi on July 18, 2010 at 8:02 am

  Hi!

  I have an expression on the opacity of a solid.
  Here is the expression I have so far:

  life = 5;
  offset = 0;
  SeedRandom(index,true); 
  pause = random(life+offset);
  if(time < pause)
  age = 0;
  else
  age = (time-pause) % life;

  The variable \”age\” pauses at 0, increases, resets back to 0 when it reaches 1 and repeats the same thing again.
  I\’m trying to increace the opacity from 0-100 as age inceases from 0-0.2 and for the opacity to decrease back from 100-0 from 0.8-1 (1 and 0 are the same as it loops back with the % sign)
  Is this possibe and if so, how?

  Thanks in advance!

  John Toi replied 16 years, 1 month ago 2 Members · 2 Replies
• 2 Replies

• 

  Dan Ebberts

  July 18, 2010 at 7:19 pm

  This might be what you want:

  
life = 5;
offset = 0;
seedRandom(index,true);
pause = random(life+offset);
if(time < pause)
age = 0;
else
age = (time-pause) % life;

  if (age < .2)
linear(age,0,.2,0,100)
else
linear(age,.8,1,100,0)

  Dan
• 

  John Toi

  July 19, 2010 at 1:33 pm

  Amazing! Thanks for the quick response!

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