I have a set of 2d layers and would like to do a parallax scale with them using a null object and an expression for each layer. I have all my layers parented to a null object, but I can't figure out an expression that works. I want to scale up the null object, and then the layers scale differently based on a variable in an expression. For example, mountains in the background will scale much slower than the bushes in the foreground, but this both happens while scaling one null object. Any suggestions? Thanks!