black glass refraction?

[mommus]

Hi guys,

   I've been rendering an interior scene of a barn conversion I'm designing.

   I've used a Corona sun for the external light with the sunlight shining through a large run of windows.

   There seems to be a strange dark area in the shadow/refracted sunlight cast on the floor - it resembles the shadow of a fir tree - but it isn't there when the refraction of the glass material is overridden (or when the glass is hidden). It's at the bottom left of the image.

   The glass material is a very simple standard setup with an IOR of 1.05



   Has anyone else had this issue?

[maru]

It really does look like a tree. Do you have a tree object in your scene? Maybe it's hidden?

[mommus]

Definitely no trees there

If I hide the glass, or tick Thin (no refraction) the artifact doesn't show up.

[romullus]

Maybe there's some overlapping polygons?

If you hide everything except sun, glass and floor objects, does problem persists? If yes, could you upload scene with only those objects?

[mommus]

Still happening if I isolate sun, floor and glass

also still happens whether Corona Sky is on or off.

I'm confused

[mommus]

just looking at it now - it seems that the black area is actually the direct reflection of the sun - but inverted for some reason

if I remove everything but the sun and the floor, the sun itself is reflected in the floor, but for some reason when it is refracted through the glass, the direct reflections of the sun are black

unticking any of the boxes under 'Visibility' in the Corona sun dropdown seems to make no difference - replacing the glass texture with a new one, and replacing the glass geometry doesn't seem to help either

[maru]

Can you upload the scene or similar with this effect? :)

[drado226]

i want to see this scene , you must upload floor map too, im very curious

[mommus]

where should I upload the scene to?