• Adobe After Effects Expressions

  Delayed Opacity Rampdown

  Posted by Sebastian Martinez on June 2, 2010 at 11:03 am

  hi guys,
  here this one:

  i have a slider controle from 0 to 100. from the point of time that slider reaches 100 the opacity of another layer ramps down from 100 to 0 over 1 sec.

  i went a whole day through the ae expression forum and didn’t find anything that combines an if/else function with a rampdown.

  very difficult, i’m still a newbe to expressions.

  respects
  sebastian

  Sebastian Martinez

  Sebastian Martinez replied 16 years, 2 months ago 2 Members · 2 Replies
• 2 Replies

• 

  Dan Ebberts

  June 2, 2010 at 3:13 pm

  Triggers are not as simple as you would think they should be. Basically you need to construct a loop that goes back in time, frame by frame, until you find the time where the value went from below 100 to 100. Something like this should work:

  
slider = thisComp.layer("Other Layer").effect("Slider Control")("Slider");
above = false;
f = timeToFrames();
while (f >= 0){
t = f*thisComp.frameDuration;
if (above){
if (slider.valueAtTime(t) < 100){ f++; break; } }else if (slider.valueAtTime(t) >= 100){
above = true;
}
f--;
}
if (above){
t = time - f*thisComp.frameDuration;
linear(t,0,1,100,0);
}else{
value
}

  Dan
• 

  Sebastian Martinez

  June 4, 2010 at 12:51 pm

  wow!

  thank’s dan, you are a hero.
  sebastian

  Sebastian Martinez

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