Vasari is the right software to analize how the sun path can effect shadows on fronts of buildings during a day time and all the year. It's possible to recreate the situation you are studing with 3D figures. In this way you can get a close representation of reality.
1. Start Vasari software
2. Select ''Manage'', then ''Project Units'' to set the units of measure you prefer to recreate the buildings. Click twice ''Ok.''