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After Effects 3D Position only rotate
Hi all,
trying to figure out a way to rotate layers around an axis in 3d without the actual layer itself rotating, but only taking in positional data from a null. Is there a way to do this? I guess I need to bake the positional data of the 3d null out from the rotation attribute so I can use it to parent the layer.Imagine a solar system and I need to rotate flat planets around a sun in 3D so the faces of the planets are always facing the camera.
Any hints will be appreciated.
Thanks!
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4 Replies
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apply this expression to the rotation property of your layer:
-parent.rotationnow the layer will not take into account the parented rotation information.
Roei Tzoref
After Effects Artist & Instructor
♫ Ae Blues Tutorials -
Thanks very simple, just invert the parameter!
I used:
-parent.transform.xRotationCheers
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△ As Above | So Below ▽ -
Ok, when I try rotating more than one axis, this technique falls apart. Just inverting the rotation against the null doesn’t seem to work.. I guess the math isnt right!
Any ideas?
Cheers
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Fantastic, found this incredible post here
https://forums.creativecow.net/thread/227/24188#27547Apply this expression to your orientation and it will nullify any 3D rotation inherited from the parent.
Not entirely sure how it works though!
u = fromWorldVec([1,0,0]);
v = fromWorldVec([0,1,0]);
w = fromWorldVec([0,0,1]);sinb = clamp(w[0],-1,1);
b = Math.asin(sinb);
cosb = Math.cos(b);
if (Math.abs(cosb) > .0005){
c = -Math.atan2(v[0],u[0]);
a = -Math.atan2(w[1],w[2]);
}else{
a = (sinb < 0 ? -1 : 1)*Math.atan2(u[1],v[1]);
c = 0;
}
[radiansToDegrees(a),radiansToDegrees(b),radiansToDegrees(c)]credit to Dan Ebberts
Cheers
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