Strange vertical dark area on a spherical sky

[paq]

Hello,

Any clue what's going one here ?  (see attach) I havn't done anything that crazy with the render settings.

[bigben]

I'm going to guess that this is a stitched image and not rendered with the spherical camera?

[paq]

Hi  bigben,

No, no stichting here, it's a direct terragen output, using spherical cam.

[bigben]

Wow. Haven't seen that before. Have you tried it with terrain.  It doesn't appear to be affecting the sky, only the clouds, but vertical lines evenly spaced at 24° is pretty unusual.  Is the cloud using a single node for the density? 

[Matt]

I've seen this problem occasionally in some other renders (not just spherical renders), and I think it's the GI. You might need to tweak the GI cache detail and/or the GI blur radius. What are they set to now?

Matt

[paq]

Hi Matt and bigben,

There is a terrain in the scene (basically the default scene one, I just lowered the displace elevation).

Hi Matt,

Thanks a lot for the help.
GI blur radius was on 3 ... a value of 6 resolve the problem !