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Inertial Bounce expressions suddenly not working!
Can anyone tell me why this started happening in CS6? This expression always worked before.
One theory was that the comp was too long (18 minutes). I have this in a 3 minute comp now and still get the same error. (I have used this expression in 2-3 minute comps before and not had issues.)
Also received this reply:
Not sure how to implement that, though.
Also, the expression doesn’t break right away. It works for about 30 seconds before throwing an error.
Here’s a link to the comp: https://www.dropbox.com/s/6nktob8yj8uohoi/007%20Sample%20Comp.aep
Thanks!
Mikeamp = .1;
freq = 2.0;
decay = 6.0;
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){
v = velocityAtTime(key(n).time - thisComp.frameDuration/10);
value + v*amp*Math.sin(freq*t*2*Math.PI)/Math.exp(decay*t);
}else{value}
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7 Replies
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Try it this way:
decay = 6.0;
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){
v = velocityAtTime(key(n).time - thisComp.frameDuration/10);
if (t < 2)
value + v*amp*Math.sin(freq*t*2*Math.PI)/Math.exp(decay*t)
else
value;
}else{value}
Dan
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That did it!
Thanks so much, Dan!
Best,
Mike -
@Dan;
Could you elaborate on the issue with the original expression and how replacement you graciously provided solves the problem?
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After a couple of minutes or so, Math.exp(decay*t) will become such a huge number that JavaScript represents it as “Infinity”, which I’m guessing breaks the division operation. I just limited the calculation to a couple of seconds, which is all it really needs for the decay to finish.
Dan
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Hi there,
sorry for picking over these bones, but
what could be the reason if the bouncing aborts – like in my case?
I applied the expression to the position property.
amp = 0.1
freq = 1.0
decay = 2.2 -
It looks like you’re using the version of the expression that cuts off after a couple of seconds to keep from generating a divide by zero error. You could go back, to the original expression, or increase the cut off from 2 to 10 or so, or use this version, which I like better:
https://www.motionscript.com/articles/bounce-and-overshoot.html#kf-overshoot
Dan
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Overshoot works perfectly fine. But if anyone else wants to stick to the “old” bounce expression, this is the way:
amp = .1;
freq = 1.5;
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 < 2){ //----INCREASE LATTER VALUE IF CUT OFF----//
v = velocityAtTime(key(n).time - thisComp.frameDuration/10);
value + v*amp*Math.sin(freq*t*2*Math.PI)/Math.exp(decay*t);
}else{value;
}
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