I've found some strange behaviour, and I can't find the cause of it.
If you look at the image below, you can see that on the left wall there is a "ray" of white light coming from above, as well as a line of white light in the roof.
The problem is that there is no hole in the roof, and all the lights in that part are magenta.
I have deleted the floor/ceiling and put it in again, but that doesn't solve the problem.
The design itself is very simple: just a few walls, floor/ceiling and some louvres in the ceiling to filter the light down. The only special thing is that there are MANY lights, maybe 200 or so. (here is the original file )
Who can help to solve this riddle?
Thanks in advance.
Hans