Wiggle expression triggered by multiple keyframes

[Kris Higgins]

New to expressions. Here’s what I’m trying to accomplish:

A layer has multiple keyframes changing the position. I’d like to have the wiggle expression activate with each change of position, and then have the wiggle quickly decay.

For example, from 0:00-1:00 layer position is 960,540 and wiggle is not active. At 1:05 position changes to 1200,540 and wiggle is activated and decays over 1 second. At 5:00 position changes to 300,540 and wiggle is activated and decays over 1 second.

I’m constantly adjusting the timing of the keyframes, so I’d prefer to not tie the wiggle to specific times but to the change of the keyframe values.

Any suggestions?

Thanks!

[Oleg Pirogov]

Just to throw in something to start with, this expression activates a fading-out wiggle for one second after each keyframe which has a non-zero speed at the moment just before it (which suppose to correspond to “change of position”):


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){
if (speedAtTime(key(n).time-thisComp.frameDuration/10)){
linear(time, key(n).time, key(n).time+1, wiggle(10, 100), value);
}
else{
value;
}
}else{
value;
}


[Kris Higgins]

This is fantastic. Thank you!

I’ve been trying to figure out how to link the expression to another layer with this.Comp(“other layer name”), but I can’t figure out where to place it within the expression to make it work. Somewhere within n = nearestKey(time).index;?