My windows/glazings aren contributing as much light as I think they should. What could be wrong with them?
There are 2 possible causes. To model a window correctly, make sure the surface normal of the glazing is pointing inwards. This is because a glazing is treated as a secondary lightsource, an “illum”. (English translation: “A surface through which or by which large quantities of light are directed”.) If the surface normal is pointing out of the room, you will still be able to see the view and the sun outside, but the light contribution from outside will not be accurately accounted for inside the model. Check the glazing surface normals by using the radiance tool, Radiance–>Tools–>Adjust Surface Normals. Also, make sure the glazing is modeled as a single surface. Having two panes of glass close together does not simulate a double-pane glazing! All of the glazings in the Desktop Radiance Library are meant to be attached to single surfaces only, regardless of their real life counterparts (See also FAQ: Where is Desktop Radiance getting its glazing data from?).
