Control position and scale from another comp

[Steve Sierra]

Hello again,

I made a few changes: instead of the “MaskedLayer” position, I used the center of “PreComp”. (I’m thinking I should maybe use “PreCompLayer”s anchorPoint ?)
I managed to get both position and rotation to work, but I still can’t figure out how to incorporate “preCompLayer” scale changes.
I think I have to use preCompLayer’s scale and maybe the size ratio between MasterComp andPreComp in my expression… but I don’t know where and how ?

Any help would be greatly appreciated !
Here’s my new expression for PreCompNull’s position:

preCompLayer=comp(“MasterComp”).layer(“PreCompLayer”);
a = preCompLayer.transform.position;
s = preCompLayer.transform.scale;
b = comp(“MasterComp”).layer(“MasterLayer”).transform.position;
d =[comp(“PreComp”).width/2comp(“PreComp”).height/2];
c = fromWorld(a)-fromWorld(b);
lightPos=d-c;
preRot= -preCompLayer.transform.rotation;
eRot=degreesToRadians(preRot);
eCos=Math.cos(eRot);
eSin=Math.sin(eRot);
u=lightPos-d;
x=eCos*u[0]-eSin*u[1];
y=eSin*u[0]+eCos*u[1];
[d[0]+x, d[1]+y];

[Steve Sierra]

Oops, forgot a comma :

preCompLayer=comp(“MasterComp”).layer(“PreCompLayer”);
a = preCompLayer.transform.position;
s = preCompLayer.transform.scale;
b = comp(“MasterComp”).layer(“MasterLayer”).transform.position;
d =[comp(“PreComp”).width/2, comp(“PreComp”).height/2];
c = fromWorld(a)-fromWorld(b);
lightPos=d-c;
preRot= -preCompLayer.transform.rotation;
eRot=degreesToRadians(preRot);
eCos=Math.cos(eRot);
eSin=Math.sin(eRot);
u=lightPos-d;
x=eCos*u[0]-eSin*u[1];
y=eSin*u[0]+eCos*u[1];
[d[0]+x, d[1]+y];

[Steve Sierra]

Hi again,

Ok, I think I got it…
Here’s a recap :
Let’s say you have layer(“Alayer”) in “Acomp”.
in “Bcomp”, you have layer(“Acomp”) and layer(“Blayer”).
“ALayer’s” AnchorPoint and Position have to be set at the center of the comp.
No parenting anywhere.

If you want to drive layer(“Alayer”) with layer(“Blayer”),
regardless of :
-“Acomp” and “Bcomp” size difference
-layer(“Acomp”)’s pos, scale, rot and anchor point’s location

put this expression in the Anchor Point property of “Alayer” :

//Raw Variables
AcompLayer=comp(“Bcomp”).layer(“Acomp”);
d = AcompLayer.transform.anchorPoint;
s = AcompLayer.transform.scale;
h = AcompLayer.transform.position;
g = comp(“Bcomp”).layer(“Blayer”).transform.position;
//
//Counter Scale
function CounterScale(Pos, s){
return [Pos[0]*100/s[0], Pos[1]*100/s[1]];
};
a = CounterScale(h, s);
b = CounterScale(g, s);
c = fromWorld(a) – fromWorld(b);
scaledPos = d + c;
//
//Counter Rotation
preRot = -AcompLayer.transform.rotation;
eRot = degreesToRadians(preRot);
eCos = Math.cos(eRot);
eSin = Math.sin(eRot);
u = scaledPos – d;
x = eCos*u[0] – eSin*u[1];
y = eSin*u[0] + eCos*u[1];
[(d[0] + x), (d[1] + y)];

Put this in “Alayer’s” Scale property :

//Counter Scale
a = comp(“Bcomp”).layer(“Blayer”).transform.scale;
b = comp(“Bcomp”).layer(“Acomp”).transform.scale;
c = [a[0] * 100 / b[0], a[1] * 100 / b[1]];
//
//Add Controller Scale
d = comp(“Bcomp”).layer(“Blayer”).transform.scale;
[c[0] * d[0] / 100, c[1] * d[1] / 100];

And this in “Alayer’s” Rotation property :

a = comp(“Bcomp”).layer(“Blayer”).transform.rotation;
b = comp(“Bcomp”).layer(“Acomp”).transform.rotation;
a – b;