I'm trying to investigate the effect of various screen shading systems on a west facing window but getting odd results.

I'm working on a simple box with one window but the direct solar gain of the zone refuses to respond as expected to elements in front of the window. I have the screen element on a non-thermal zone and have tested changing the normals.

I sometimes get very small changes to basically covering the window, but nothing even remotely sensible.

any ideas?

cheers