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Adding Inertia or Bounce on a Shape Layers Path?
I was wondering if it is possible to add an intertial bounce to the the path property of a shape layer?
I have a shape layer with one filled path within a group, I have animated the path property of this shape to grow and want to add an intertial bounce (or any bounce) to this growth. When I try to add the expression, I receive the error “After Effects error: can’t compute derivative to a non-spatial custom value ( 29 :: 57 )”.
I did some digging and could only find this thread about using expressions on paths, and am wondering if there is a way to make my path bounce via expressions.
The expression I am trying is from here, and I’ve included it in the post as well. Thanks for any help!
amp = .1;
freq = 2.0;
decay = 2.0;
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} -
8 Replies
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I don’t think there’s a good way to get there with expressions because expressions can’t do any math on paths. You can link to other paths and use valueAtTime(), but that’s pretty much it.
Dan
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Gotcha. Thanks for the confirmation on that. I wonder if it is a technical limitation in scripting, or if it could be a feature request.
Thanks for the help!
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Hi!
sorry for bringing back this old post,
do you think it’s now possible to add bounciness to a shape layer path animation with the new cc 2018 features? -
Yes, it seems to work. It simplifies things if you can assume that the tangents remain constant and that the number of points doesn’t change. Something like this should work:
n = 0;
if (numKeys > 0){
n = nearestKey(time).index;
if(key(n).time > time) n--;
}
if (n > 0){
p0 = thisProperty.points(key(n).time - thisComp.frameDuration/10);
p1 = thisProperty.points(key(n).time);
p = [];
pCur = thisProperty.points();
t = time - key(n).time;
freq = 3.0;
decay = 5.0;
m = Math.sin(freq*t*2*Math.PI)/Math.exp(decay*t);
for (i = 0; i < p0.length; i++){
v = (p1[i] - p0[i])*10*m;
p.push(pCur[i] + v);
}
createPath(p,thisProperty.inTangents(),thisProperty.outTangents(),thisProperty.isClosed());
}else
value
Dan
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totally awesome, thanks!
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<3
manojit ghose
+48512875636
skype/ gtalk: manojitghose -
Just wanted to add to this as the initial expression doesn’t have an amplitude which you can adjust.
n = 0;
if (numKeys > 0){
n = nearestKey(time).index;
if(key(n).time > time) n--;
}
if (n > 0){
p0 = thisProperty.points(key(n).time - thisComp.frameDuration/10);
p1 = thisProperty.points(key(n).time);
p = [];
pCur = thisProperty.points();
t = time - key(n).time;
freq = 3.0;
decay = 5.0;
amplitude = 0.08
m = (amplitude * Math.sin(freq*t*2*Math.PI))/Math.exp(decay*t);
for (i = 0; i < p0.length; i++){
v = (p1[i] - p0[i])*10*m;
p.push(pCur[i] + v);
}
createPath(p,thisProperty.inTangents(),thisProperty.outTangents(),thisProperty.isClosed());
}else
valueadded an amplitude to this
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Awesome! Thanks! Very usefull!
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