Still no solution I guess?
I’m doing a cartoon character eye/pupil that I want to project onto the eyeball (which is not a ball) in a similar fashion but unless I want to refrain from using any decals (blood, paint, damage etc.) on the character’s face/skin, I can’t use decals for this.
The eyeball deforms as the character is animated but I want the pupil to stay the same size/undeformed. So far I have been making extra uv maps for each position and lerping towards them similar to shapekeys/morphs and it actually works but it’s a pain if I want to move the pupil around as well.