• Adobe After Effects Expressions

  I must be busy this morning, continued!

  Posted by Olly Bea on April 11, 2008 at 3:16 pm

  Hey

  Following from my earlier post (I must be busy this morning, 2 posts!) I would like to try and generate a new position each time opacity = 100 but hold in that position until opacity reaches 0.

  The current code I have in opacity:

  prop=thisComp.layer(“Bass 3”).effect(“Both Channels”)(“Slider”);

  threshold=5;
  fadeOut=1; // in seconds

  t=time;
  while (t>time-fadeOut) {
  if (prop.valueAtTime(t)>=threshold) {
  break;
  }
  t-=thisComp.frameDuration;
  }

  linear (time, t, t+fadeOut, 100, 0)

  Many thanks

  Olly

  Olly Bea replied 18 years, 1 month ago 2 Members · 2 Replies
• 2 Replies

• 

  Filip Vandueren

  April 11, 2008 at 4:00 pm

  Hi,

  a different approach this time, because now the expression has to scan from the beginning, and count how many times the threshold has been met.
  I referencing the original Audio data, instead of the opacity:

  
prop=thisComp.layer("Bass 3").effect("Both Channels")("Slider");

  threshold=5;
  peaks=0;

  t=0
  while (t<=time) { if (prop.valueAtTime(t)>=threshold) {
  peaks++;
  }
  t+=thisComp.frameDuration;
  }

  seedRandom(peaks,timeless=true);
random([0,0],[720,576]);


  This first counts the number of peaks from time 0 untill current time, then uses that number to find a random position between [0,0] and [720,576]
• 

  Olly Bea

  April 11, 2008 at 4:21 pm

  superb thanks very much!

Reply to this Discussion! Login or Sign Up