Hi all,
I seem to run into the same problem with displacements on glass every time, and it's driving me nuts!
1) I make my model, surfaces, scene and lighting. Everything looks great.
2) Then I apply displacement without texture - everything still looks great.
3) I put in a texture and BOOM! My glass loses it's perfect refracting appearance and becomes flat. Naturally the first thought is that surfaces start to intersect in weird ways due to the displacement, so I set the displacement distance to zero to go to a "base" version again.
4) Nada: my glass keeps looking like crap. Even turning down the texture power to 0 and so on doesn't change this.
How come having displacement with theoretically zero amplitude makes my glass look so different, and how can I fix this???
Attached are 2 screenshots: one nice one of the glass with displacement node disconnected, and one where it's connected but with amount set to zero, and still messing up my glass.
FYI, I'm rendering with PMC kernel and have tried setting ray epsilon from 1um to 1mm but nothing changes...