I think they are too neat, for one thing.

I don't think the cobweb would look so quarter round wish in the corner.
It is about how it hangs from the ceiling with only two perpendicular sides.
Cobweb among the tree is different, because the spider can have support from all angles. But ceiling or corner of ceiling the most you have is 3 sides.
So in perspective of the avatar angle, the cobweb won't drop like that. It would be askew...
Kind of like a round lamp, do not look round in eyeview.