Re: Projecting 3D to 2D with toComp()

Just figured it out through trial and error, and it works beautifully!

v = A + t*(B-A);
cam.toComp(cam.fromWorld(v));

Of course my full code also includes a lot of testing to see which layer/point needs to be clipped as well. Here it is for the target 'end' point:

nearClip = 5;
cam = thisComp.activeCamera;
l1 = effect("Source")("Layer");
l2 = effect("Target")("Layer");
n = cam.toWorldVec([0,0,1]);
c = cam.toWorld([0,0,nearClip]);
a = l1.toWorld(l1.anchorPoint);
b = l2.toWorld(l2.anchorPoint);
r = l2.toComp(l2.anchorPoint);

da = dot(a - c, n);
db = dot(b - c, n);

if((da < nearClip)&&(db < nearClip)){
[-100,-100];
}
else if((da > nearClip)&&(db > nearClip)) r;
else if(db < nearClip){
t = dot((c-a),n)/dot((b-a),n);
v = a + t * (b-a);
cam.toComp(cam.fromWorld(v));
}
else r;

Darby Edelen