It´s weird but I think I got it. Correct if I´m wrong please.
You want the circle to appear to be changing size, but actually it´s not.
i.e. you see the circle smaller and bigger but if you check the scale it´s still 100% on both moments.
Is that it?
If it is I guess I would try something like turning the cirlce layer 3D and animating it´s Z axis. If the circle is not on the center of the main comp I would precomp it first. Put it on the center of the precomp and moving the precomp around the main comp.
Sorry if I made it more confusing but I just thought that….
Hope it helps.
Cheers.
ninguem
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