How to animate the size (width and height) of a rectangle animation in after effects? I want to change the height of a rectangle bottom - top from 0 to 1080px starting from position -1080 to 0. How do I do that? By default the transform does not have a size. It does have a scale but it's blurring out the edges when I'm trying to do the same with it.
Why not just start with a full screen square and simply position it off the bottom of the frame.  You can then simply animate it moving up.  Even if you have something on the square, it will generally look better to slide in than stretch in.  If there isn't anything on the square, it will look the same either sliding or stretching in if I understand your scenario correctly.