Good Morning @mikkel , I tried to create the blinds as simple surfaces (only one flat blind surface per window) to simplify the geometry, maybe that could be the problem, but it brings me the same error [fatal - unexpected EOF in header].
I now read your response to this post: Error when I create a Radiance custom material (HB+) - #2 by mikkel, couldn’t I use this type of script to give out the mixfunc perforated material and bypass the RadScene?