This should give you the position:

 

L = thisComp.layer("parented null");

L.toWorld(L.anchorPoint);

 

And this should give you the orientation:

 

L = thisComp.layer("parented null");

u = L.toWorldVec([1,0,0]);

v = L.toWorldVec([0,1,0]);

w = normalize(L.toWorldVec([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)]

 

 

Dan

 

 

From: Byron Nash

Sent: Monday, September 17, 2012 10:20 AM

To: After Effects Mail List

Subject: Re: [AE] Layer Space transform onto parented layers

 

How about the other direction? I have a layer that is parented inside a heirarchy. I need to match another layer to it that is unparented. Most of the motion is from the parent layers rotation. Also, I have moved the anchorpoints around so they are not in the center.  I am trying different combinations of toWorld and fromWorld and can't seem to get it working. I need another one on the rotation to get it oriented correctly, would that go on Orientation or the individual axes?

On Wed, Sep 5, 2012 at 6:06 PM, Darby Edelen <dedelen@gmail.com> wrote:

This line:

parent.fromWorld(p);

Should work no matter how deeply parented the null is. The reason being that it will take a world position (p) and transform it into the local/layer space of the current layer's parent. This is exactly how a child's position is defined (i.e. in the parent's local/layer space).

The part that is really important is the parent.fromWorld(). You could put any world coordinate in there and it should work.

On Sep 5, 2012 11:19 PM, "Byron Nash" <byronnash@gmail.com> wrote:

Thanks for the expression. I haven't had a chance to test it yet. I did not think of stacking the toWorld and fromWorld. What if the parented null is several parent layers deep?

On Wed, Sep 5, 2012 at 12:39 PM, Darby Edelen <dedelen@gmail.com> wrote:

In order to transform the parented null to the unparented null you'll need to use an expression in this form; applied to the parented null's position:

l = thisComp.layer("unparented null");
p = l.toWorld(l.anchorPoint);
parent.fromWorld(p);

I can't confirm this is correct at the moment, but it should at least be close.

On Sep 5, 2012 5:37 PM, "Byron Nash" <byronnash@gmail.com> wrote:

I need to "constrain" one null to another with Layer Space transforms. The null that I am matching FROM is not parented at all. The one I am wanting to add the expression TO is parented several levels deep. I have tried various combinations of toComp, fromComp, toWorld, fromWorld, etc... What is the proper way to apply a comp position value to a layer that is inheriting many levels of offsets?

 

Thanks!