Weird “glitchy” displacement of objects when using several instances of the EaseAndWizz script on parented objects that move together

[Richard Herd]

Yeah that is definitely bad juju. without your project file, it’s hard for me to figure out what’s up.

I use two expressions for a similar thing. If you want it, here it is:

This one goes on the X rotation and you’ll need to include three Expression Effects:


//USES MARKERS ON THE LAYER TO SWING A LAYER
amp = effect("Pendulum At Marker")("Amplitude");
freq = effect("Pendulum At Marker")("Frequency");
decay = effect("Pendulum At Marker")("Decay");
n = 0;
t = 0;
if (marker.numKeys > 0){
n = marker.nearestKey(time).index;
if (marker.key(n).time > time){
n--;
}
}
if (n > 0) t = time - marker.key(n).time;
a = amp*Math.sin(freq*t*2*Math.PI)/Math.exp(decay*t);
value + a


This one goes on the position layer of the “lower layers” (the original layer stays in its position.


// SCRIPT GLUES LAYERS TOGETHER USING PRECOMP AND SCRIPT
center=thisComp.layer("White Solid 2 Comp 2").transform.anchorPoint;
angle=degreesToRadians(thisComp.layer("White Solid 2 Comp 2").transform.xRotation);
radius= 265;
x=radius*Math.cos(angle);
y=radius*Math.sin(angle);
add(center, [transform.position[0]-center[0],x,y]);


Sources:
The first expression is from Adobe’s Expression Sampler; since you control the decay through an Expression Effect, your key frames go on the X rotation. I wrote the second expression.

[Xavier Bonet]

Thanks a lot for your response, Richard! And sorry about not including my project file… forum amateur mistake!
Here’s the culprit project file: 10028_outroglitch.aep.zip
And here’s my second amateur badge: how do I include the 3 Expression Effects? Because obviously I just copied and pasted your code and got an error, which corroborated that I was missing something: the “Pendulum At Marker”.
I’m afraid I’m not following you…
Thanks again for your input!

[Xavier Bonet]

I’m not meaning to add this as the answer to my issue, becausue it’s not. I’m still interested in knowing why the EAW script is glitching out. However, for practical purposes, I decided to stop looking at the problem and finding a solution, and start looking at another way out, that is, another way to do the thing.
Richard Herd’s post got me thinking that really I was obsessing a little on the issue with the EAW and that there were other ways to achieve a fairly similar effect. One, for instance, surely Richard’s, although the amateur that I am, I can’t figuro out how to use it.
Instead, I found a simple elastic/bouncy expression online and tweaked it with the values I needed to get an effect as close to the one I want.
For what it’s worth, in my case, right now, with the urgent deadline ahead, this is my solution or rather way-around the issue of the EAW glitch:
// Inertial Bounce (moves settle into place after bouncing around a little)
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){
v = velocityAtTime(key(n).time - thisComp.frameDuration/10);
amp = .05;
freq = 4.0;
decay = 2.0;
value + v*amp*Math.sin(freq*t*2*Math.PI)/Math.exp(decay*t);
}else{
value;
}

[Richard Herd]

Sorry for the delay. But yeah, I use Inertial Bounce all the time!