• Adobe After Effects Expressions

  Adding function to an expression

  Posted by Alekos Mazzolotti on June 22, 2020 at 10:10 pm

  Hi!

  So, i’ve been using the following expression (pasting a “short version” of it) to add automatic behaviors to the start/end of a layer, at properties such as opacity.

  Now, I had this idea of applying the same expression to the “end” property of a trim path animation. And it does work. Except that… For some properties (e.g. position), I like to shape my speed like this:

  

  And the built in “ease out” function produces nothing of the sort. So, researching over the internet I came across this magnificent site:

  http://gizma.com/easing/#expo3

  And, in it, I found the following function to be added to my expression:

  Math.easeInOutExpo = function (t, b, c, d) {
  t /= d/2;
  if (t < 1) return c/2 * Math.pow( 2, 10 * (t – 1) ) + b;
  t–;
  return c/2 * ( -Math.pow( 2, -10 * t) + 2 ) + b;
  };

  The question is: how can I integrate this function to my already working expression?

  dur = Math.round(effect("Slider Control")("Slider"));

  StartIn = inPoint;
  StartOut = inPoint + dur;

  EndIn = outPoint - dur;
  EndOut = outPoint;

  if (time>=StartIn && time <= StartOut)
ease(time,StartIn,StartOut,0,100);
else if (time>=EndIn && time <= EndOut)
ease(time,EndIn,EndOut,100,0);
else
value;

  Alekos Mazzolotti replied 6 years, 2 months ago 2 Members · 2 Replies
• 2 Replies

• 

  Dan Ebberts

  June 23, 2020 at 7:06 am

  I’m not sure if this is what your looking for, but it might be like this:

  
myEase = function (t, b, c, d) {
t /= d/2;
if (t < 1)
return c/2 * Math.pow( 2, 10 * (t - 1) ) + b;
t--;
return c/2 * ( -Math.pow( 2, -10 * t) + 2 ) + b;
};

  dur = Math.round(effect("Slider Control")("Slider"));
if (time < (inPoint+outPoint)/2)
myEase(time-inPoint,0,100,dur)
else
myEase(time-(outPoint-dur),100,-100,dur)


  Dan
• 

  Alekos Mazzolotti

  June 24, 2020 at 3:24 am

  Man, I love this forum ?

  Ended up with my own combined function, to ease cubic in and exponential out. Turns out all I really needed was to get this function thing right. Never used it before.

  I’ll share my final result in a simplified version, case anyone desires to make good use of it.

  Thanks a lot for your help =)

  myEase = function (t, b, c, d) {
t /= d/2;
if (t < 1) return c/2*t*t*t + b;
t --;
return c/2 * ( -Math.pow( 2, -10 * t) + 2 ) + b;
};

  dur = 1
myEase(time-inPoint,1,100,dur)

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