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Don’t run every frame
Hey guys,
I’m wondering if there’s a way to create a random position, but then hold that random position, from when an even triggers until it ends.
Essentially, my event is
a = effect("Advanced Lightning")("Core Radius");When a is not equal to 0, I’d like my script to calculate (and most importantly hold on to) a new position.
a = effect("Advanced Lightning")("Core Radius");if (a != 0) {
x = random(0, 3840);
y= random(0,768);
curPos = [x,y];
}However, the way this works is that for every frame a is not 0, I’m given a new random position.
Is there a way to trigger this the first time a changes from 0 to another value. I thought maybe a do/while would work, but that’s timing out AE’s engine.Any help would be appreciated. Thanks heaps!
Lead VFX and Motion Design at Tomorrowland NZ
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3 Replies
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Hey Ad, check this thread covered, might be helpful for your case to catch the difference: https://forums.creativecow.net/thread/227/40694
Find out more:
After Effects Tutorials: motion design, expressions, scripting. -
You just saved my butt. I knew about seedRandom but did not know about the “timeless” second argument! Thanks heaps 🙂
Lead VFX and Motion Design at Tomorrowland NZ
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a = effect("Advanced Lightning")("Core Radius");seedRandom(index,true); // "index" could be any number; ",true" makes sure the _same_ random numbers are always generated.
fd=thisComp.frameDuration;p=random([0,0], [3840,720]); // even if this is called every frame, it will always return the same random number
// we have to loop through time and check how many times "a" has become 0
// by generating a random number for each occurrence of a=0 but was not 0 one frame ago,
// every subsequent random() call yields a different random number.for (t=0; t<=time; t+=fd) {
if (a.valueAtTime(t)==0 && a.valueAtTime(t-fd)!=0) {
p=random([0,0], [3840,720]);
}
}p;
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