After Effects Quick Tip | Inertial Bounce

By October 18, 2019After Effects, Quick Tip

Do you want to add life to your text or logo animations?

I use Harry Frank’s Inertial Bounce expression in most of my After Effects projects.

Add this to the position, scale, or pretty much any property.

amp = .025;
freq = .8;
decay = 8.0;
n = 0;
if (numKeys > 0){
n = nearestKey(time).index;
if (key(n).time > time){
n--;
} }
if (n == 0){
t = 0;
}else{
t = time - key(n).time;
}
if (n > 0 && t < 1){
v = velocityAtTime(key(n).time - thisComp.frameDuration/10);
value + v*amp*Math.sin(freq*t*2*Math.PI)/Math.exp(decay*t);
}else{
value;
}

You don’t have to understand what’s going on in this expression to use it properly. I only adjust the second and third lines. I’ll change the value for “freq” and “decay”. I’ve noticed that a small number for “freq” paired with a larger number for “decay renders a subtle inertial bounce.

This expression helps you follow a couple of Disney’s 12 Principles of Animation.

  • Slow in and slow out
  • Timing

Disney’s 12 Principles of Animation:https://ohmy.disney.com/movies/2016/07/20/twelve-principles-animation-disney/

Check out more of Harry Frank’s expressions. https://www.graymachine.com/top-5-effects-expressions https://www.graymachine.com/expressions