After Effects Expressions Nerd Tip 2: toComp and fromComp (1 minute tutorial)
62https://aescripts.com/learn/after-effects-expressions-nerd-tip-2-tocomp-and-fromcomp--1-minute-tutorial-
The toComp and fromComp functions of After Effects expressions can be confusing - but they don’t have to be! Watch this 1 minute tutorial to understand how they really work and how to use them. An an example, we link the center of a circle effect on one layer to the center of a circle on a second layer such that they always stay in place no matter how you move, scale or parent any of the two layers.
Expression used in the Tutorial
var posInOrangeLayerSpace = thisComp.layer("orange solid").effect("Circle")("Center");
var posInCompSpace = thisComp.layer("orange solid").toComp(posInOrangeLayerSpace);
var posInGreenLayerSpace = thisLayer.fromComp(posInCompSpace);
posInGreenLayerSpace