The image of Eru

[Kin-strife]

I always imagined that the music of the Ainur took place on a more spiritual plane of existance where (though there is no real textual evidence for this)sight doesn't exist on the level that we find it. As if things are perceived in full rathar than just seen in 2D from your particular vantage point.
It says in the Ainulindale that the Valar's shape comes from "their knowledge of the visible World, rathar than the World itself". It then goes on to say that without their shape they would suffer no loss of being.
This suggests to me that the Ainur could perceive, or "behold", Ilùvatars face wheteher they could "see" it or not.
I might be able to explain myself better. In the vision shown them of the World the valar might have perceived, along with everything else, sight (in our sense of the word) for the first time. i.e the way we see things from an angle or perceive the distance of an object from the size that it appears our view. Perhaps this kind of vision, previously, didn't exist.