@theluthier Thank you. 🙂 I did try adding the Solidify modifier, but even when I applied it and recalculated normals, there was no change. The corner is lit by the lamps that are pointing through the window, not by the HDR. But there is a weird thing with the lamps – the light doesn’t change when I rotate them on the Z axis, only when I move them around. Almost as if the direction of the light beam was ignored. And regarding the global illumination – is that an option I need to turn on somewhere?
