expression for 3D orientation

[Mylenium]

Use the lookAt() method. It does basically the same as orientation parameters.

Mylenium

[Pour Myl

[Ryan Chan]

sorry, what i mean is, can i extract the value from the 3D Auto orientation, so i can use it for other reason(layer). thanks

[Dan Ebberts]

Try this:

L = this_comp.layer(“Layer 1”);
s = L.scale/100;
u = L.to_world_vec([s[0],0,0]);
v = L.to_world_vec([0,s[1],0]);
w = L.to_world_vec([0,0,s[2]]);
sinb = clamp(w[0],-1,1);
b = Math.asin(sinb/this_comp.pixel_aspect);
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 = Math.atan2(u[1],v[1]);
c = 0;
}
[radians_to_degrees(a),radians_to_degrees(b),radians_to_degrees(c)]

Substitute your layer for “Layer 1”.

Dan

[Ryan Chan]

thanks so much, Dan

[Filip Vandueren]

Hi Dan,

I can’t test this for the moment,
but would this expression sum up all the rotations for e.g.
a camera that is Auto-oriented + keyframed for rotation + keyframed for orientation ?

if so: brilliant stuff, just what I needed for a problem I was working on 😎

on a related note: do you think it is feasible in Javascript to convert an After Effects style 3D Euler rotation to a VRML-style axis+angle rotation ?

[Dan Ebberts]

>would this expression sum up all the rotations

It seems to. Except possibly in a gimbal lock situation.

>if so: brilliant stuff

Thanks! 🙂

>do you think it is feasible in Javascript to convert an After Effects style 3D Euler rotation to a VRML-style axis+angle rotation ?

I’m not that familiar with VRML, but it seems like it should just be a matter of cooking up the right transform.

Dan