Lights and knock outs!!

Hi guys,
I have been strugeling to get this scene with the right lighting,
this is the result after 24 hours of test renders, and adjustments,
It is okay, but for some reason I keep getting those little black boxs on the windows.
I didnt get them in the test renders, but when I did a full OSA high quality render, they should up.

Can any one tell me what these boxs are all about, and how to better light this scene, cause it will be the scene for an animation so I need consistent light when I move the camera around,
Thanks folks


It might be something in your material settings for the window glass. Just guessing, but try turning down the ray depth.

That sounds like a good liklyhood of my proplem.
Thanks I will look into it.
Thanks for your help

Let us know if that works, I am curious as to the nature of these artifacts.

I tell you one thing I noticed about my situation,
When I had the OSA set to 16 they showd up in my render,
but with an OSA of 8 or less they were not there,
and another thing is they showed up in the same spot in eeach render, it did not change as I made new renders.

weird, I guess it’s something to do with the osa. I wonder if those black lamp posts have anything to do with it? I doubt it though. You should see if you can repeat it in an earlier version. If it doesn’t happen in an earlier version, I guess it would be a bug of some sort. If it is, the coders would want to hear about it.