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Combining two expressions
I’m trying to combine two scripts to achieve the path shown in this image: https://members.shaw.ca/pdebay/spiral.jpg
I started with a ‘bounce between two points’ expression:
origin = [thisComp.width/2, thisComp.height/2];
dest = effect(“end”)(“Point”);
amp=24;
decay=1.2;
dest + (origin – dest)*(Math.exp(-decay*time)*Math.cos(amp*time));and tried to combine (by way of an average) with a circular motion (orbit around middle of comp) expression, but the result is the bottom path in the image.
Any help is appreciated in achieving the top path.
thanks, Pdebster
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3 Replies
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Not sure about your setup, but play around with this:
rMax = 150;
decay = .3;
freq = 6;
aStart = 0;
aRate = 270;
offsetFactor = 10;r = rMax/Math.exp(time*decay);
a = degreesToRadians(aStart + aRate*time);
offset = (r/offsetFactor)*Math.sin(freq*time*Math.PI*2);
center = [thisComp.width/2, thisComp.height/2];
center + [Math.cos(a),Math.sin(a)]*(r + offset);Dan
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Dan,
That works beautifully – it is a true pleasure for all of us to have access to your abilities and your generosity.
I will now attempt to figure out your handiwork,
regards, Pdebster -
Through the magic of Dan’s expression and nab’s Create Custom Effect script, I created an .ffx for creating a crenelated or ‘scalloped’ spiral effect through the write-on effect. Who knows if it’s useful in and of itself, but it goes to show the power under the AE’s hood (and of online collaboration).
I’ve posted an image here:
https://members.shaw.ca/pdebay/cren.jpganyone can email me pdebay@shaw.ca if they want creation/install instructions (you’ll have to tinker with the PresetEffects.xml file at your own risk)
thanks again, Dan and nab,
Pdebster
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