Try throwing this expression on a 3D layer's scale property with a camera in your scene named "Camera 1"

camZ = thisComp.layer("Camera 1").position[2] * -1;

layerZ = position[2];

scaler = (1/(camZ / layerZ)) * 100 + 100;

[scaler, scaler, scaler]

When you move the layer around in Z, it'll scale to appear the same size from the camera's point of view.  Then create another camera that you animate -- when the second camera matches position with the original camera, all your objects will line up.

I made this a long time ago, but if I recall correctly, it may be off if you use a camera that isn't 50mm, but it should get you started at least!  There's probably a more elegant way to do this that Dan Ebberts has already figured out.  ;)

 - Nathan

On Thu, Jan 23, 2014 at 3:16 PM, Rachel Max <rachelmax@mac.com> wrote:

Hi again, in the vein of the anamorphic illusions - is there a script or trick to affect the Z of a layer, but have it appear as if it hasn’t moved by scaling it and changing it’s position?

I’ve been eyeballing it but that has to be an easier way or some math I can do.

Thanks,
Rachel