Weird refraction issue

[Macker]

Guys,

I have got a very strange issue appearing on some glass. See attached.

I've checked all the normals are facing the correct direction, I've checked that there's no duplicate geometry, I've checked that all the glass has the same material, I've checked other objects around, I've checked/cleared the smoothing groups.

[Macker]

Update: Having deleted some of the problematic panes of glass and replaced them with new, the problem goes away - however doing this around the entire building will be incredibly time consuming, so I would still like to get to the bottom of what's causing it.

[Morne]

Have you tried clearing smoothing groups?

[Morbid Angel]

try converting them to editable poly, also check to see that the render visibility in refraction is enabled.