Hi Matthias,
Thank you for your very helpful instruction and insight.
Regarding modeling on a terrain (Ans 1), since we plan to import models that are cut to the imported terrain and occasionally use the Polygon Creation Tool to create additional models in that environment, will this concern be addressed in the future?
I tried your suggestion of reversing faces that were not showing in the web scene (ans 3) and that fixed the missing faces concern. The reversing of the rooftop in CE, however, hides the applied roof texture from normal view. I also noticed that both of the building shapes I created had reversed rooftops. (I attached screenshots of my experience). Also when I toggled the 'L' key and the 'Single-Sided Lighting', the rooftops went black as you advised, however, the reversed walls of the shapes did not.
Thank you again for your assistance,
Scott