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Can the cover geometry not just be made a sub-group of the eyeball geometry and thereby be controlled by the same actor?

It can, indeed, and everybody else does that. What you lose is the ability to use refraction on the cover, because then it casts a shadow and the iris is not lit. If we make it transparent, then no problem, but I do not want to use transparency, I want to use refraction.

So, because there is no way to make some polygons in an actor cast a shadow and others not, except through transparency, it is required that the cover be a separate actor. I have it parented to the eye so its no big deal. Plus, it lets you hide the covers so you can work with pupil dilation morphs (which otherwise you cannot see in preview).

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Renderosity forum reply notifications are wonky. If I read a follow-up in a thread, but I don't myself reply, then notifications no longer happen AT ALL on that thread. So if I seem to be ignoring a question, that's why. (Updated September 23, 2019)