QUESTION:

Although the first time I built my model I had no problems I now have problems getting shade to be accurately represented. The model has eleven zones and some of the zones which should not show sun penetration through openings until late in the day are showing it in the morning - despite other zones and no windows being between the offending zone and the sun.

ANSWER:

Difficult to say without seeing your model. To be honest it sounds like there is something wrong with some of your objects, perhaps surface normals, whether they're closed or various other things....

You could check your model using the OpenGL or hidden line views to make sure it is using solid planes in the right places. Also, check the Sun-Path relative to your building - I know its an obvious suggestion, however receiving Sun in the morning instead of afternoon does indicates a latitude issue.

Another suggestion is to isolate specific zones by turning all other zones off. Then do your shadow display or thermal runs for the specific zone. You should then be able to check it window by window (remembering that off zones will not shade or obstruct the Sun) to make sure each one is acting as you would expect. That way you should be able to quickly track down specific issues with the model (such as missing surfaces, lines that should be planes, windows that don't transmit light, etc).