Hi Cotty,
Thanks for the reply. Here's a screen shot of a current project. Shadows on ground is checked - although greyed out.

Hi, I am using 2013 Pro on Mac and despite tinkering with every setting I can think of after reading various articles on the subject, I cannot get shadows to project on the ground, or even clearly on surfaces as I have seen in others' architectural models. All that happens as I slide time and date is a subtle variation in shading on surfaces until it blacks out. Any suggestions?