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HowTo: Expression Angle Control dictates the Position of a Null

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Roland R. Kahlenberg
HowTo: Expression Angle Control dictates the Position of a Null
on Oct 11, 2013 at 3:21:43 am

As the Subject Title says BUT with an additional requirement - the Null can only move along the perimeter/edge of the Comp.

Cheers
RoRK

Intensive mocha & AE Training in Singapore and Other Dangerous Locations

Imagineer Systems (mocha) Certified Instructor
& Adobe After Effects CS6 ACE/ACI


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Dan Ebberts
Re: HowTo: Expression Angle Control dictates the Position of a Null
on Oct 12, 2013 at 11:11:50 pm

This is probably too late to help, but I finally found enough time to work this one out.


a = effect("Angle Control")("Angle")%360;
if (a < 0) a += 360;
ar = degreesToRadians(a);
w = thisComp.width;
h = thisComp.height;
g = Math.atan2(h,w);

if ((ar > Math.PI*2 - g) || (ar <= g)){
x = w;
y = (h + w*Math.tan(ar))/2

}else if ((ar > g) && (ar <= Math.PI - g)){
x = (w - h*Math.tan(ar - Math.PI/2))/2;
y = h;
}else if ((ar > Math.PI - g) && (ar <= Math.PI + g)){
x = 0;
y = (h - w*Math.tan(ar - Math.PI))/2;
}else{
x = (w + h*Math.tan(ar - 3*Math.PI/2))/2;
y = 0;
}
[x,y]



Dan



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Roland R. Kahlenberg
Re: HowTo: Expression Angle Control dictates the Position of a Null
on Oct 14, 2013 at 2:56:42 am

Thanks Dan! This worked wonderfully!

Cheers
RoRK

Intensive mocha & AE Training in Singapore and Other Dangerous Locations

Imagineer Systems (mocha) Certified Instructor
& Adobe After Effects CS6 ACE/ACI


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Madli Man
Re: HowTo: Expression Angle Control dictates the Position of a Null
on Nov 25, 2013 at 10:06:21 am

Hi Dan,

Just found this thread. This is something i wanted to do long time ago. havent found the trick. :P

I have situation here:
I found this code: that calculate degrees from position.velocity. I use linear to animate position. how can i merge this code to make animated current position to angle control? something like direction.

Thanks
Mad

v = position - position.valueAtTime(time-thisComp.frameDuration);
radiansToDegrees(Math.atan2(v[1],v[0]))




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