weird displacement artefacts

[mitchino]

I am using a displacement map to create some details on a bottle.

The bottle is UVd, the displacement map is 4K, 16bit.

I'm getting weird triangular artefacts. I've tried just about everything I can think of, but can't identify what's causing them.

Can anyone shed any light on this issue?

[mitchino]

Fixed it - I have 2 x glass materials, one for the outer surface of the bottle, and one for the inner surface - forgot to switch off the displacement for the inner material.

[jayroth2020]

Ray epsilon?