5 Mind-Blowing After Effects Expressions

In this After Effects tutorial, we will make distorted liquid stretch text, just in time for hot animator summer.

*** I did not write these expressions myself. I am not that smart even though I wish I was. Unfortunately, I do not remember where these came from, but I am assuming I saved them many moons ago from old Dan Ebberts posts.

Here are my picks for the top 5 mind-blowing expressions:

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Loop Path Animations

try{
timeStart = thisProperty.key(1).time;
duration = thisProperty.key(thisProperty.numKeys).time-timeStart;
pingPong = false; //change to true value if you want to loop animation back & forth 
quant=Math.floor((time-timeStart)/duration);
  if(quant<0) quant = 0
  if(quant%2 == 1 && pingPong == true){   t = 2*timeStart+ (quant+1)*duration - time;
}
else{
  t = time-quant*duration;
}
}
catch(err){
  t = time;
}
thisProperty.valueAtTime(t)

Random Change to Specific Colors

colors = [[0,194,209,255]/255, [115,92,221,255]/255, [179,60,142,255]/255, [242,27,63,255]/255]; 
easeTime = .2; 
segDur = 2; 
curSeg = Math.floor(time/segDur); 
t = time%segDur; 
seedRandom(curSeg,true); 
idx1 = Math.floor(random(colors.length));
seedRandom(curSeg-1,true); 
idx0 = Math.floor(random(colors.length));
ease(t,0,easeTime,colors[idx0],colors[idx1])

Pro Tip: use color controls instead of typing in the colors codes in manually.

It will look like this:

colors = [effect("Color Control")("Color"), effect("Color Control 2")("Color"), effect("Color Control 3")("Color"), effect("Color Control 4")("Color")];

Ultimate Number Counter

slider = effect("Slider Control")("Slider"); //use angle control for > million
numDecimals = 2;
commas = false;
dollarSign = true;
percentSign = false;
s = slider.value.toFixed(numDecimals);
prefix = "";
suffix = "";
if (s[0] == "-"){
  prefix = "-";
  s = s.substr(1);
}
if(dollarSign) prefix += "$";
if(percentSign) suffix = "%";
if (commas){
  decimals = "";
  if (numDecimals > 0){
    decimals = s.substr(-(numDecimals + 1));
    s = s.substr(0,s.length - (numDecimals + 1));
  }
  outStr = s.substr(-s.length, (s.length-1)%3 +1);
  for (i = Math.floor((s.length-1)/3); i > 0; i--){
    outStr += "," + s.substr(-i*3,3);
  }
  prefix + outStr + decimals + suffix;
}else{
  prefix + s + suffix;
}

Fade Layer Based on Start and End Points:

fade = 1; // fade duration in seconds
fadeIn = (time - inPoint) / fade;
fadeOut = (outPoint - time) / fade;
if (time < inPoint + fade) {
    ease(fadeIn, 0, 1) * value;
} else if (time > outPoint - fade) {
    ease(fadeOut, 0, 1) * value;
} else {
    value;
}

Trigger Opacity with Checkbox Control

if(effect("Checkbox Control")("Checkbox")==0) {0} else {100};

Pro Tip: You can swap the values inside { } for more custom results.