I'm modeling windows that have multiple external shading "fins" that cover most of the windows surface.  (Think something like vertical blinds, except external and permanently fixed.)  Trace's "vertical fin" option seems to be only for single fins to the right and left of the window, and I'm trying to find a good work-around for the way these windows are to actually be constructed.  I've attached plan, elevation and section views for reference.   As you can tell, the fins shade the vast majority of the glass, but would not have any affect on the U-Value of the assembly.