Thanks, Mitcorb. That's helpful information.
Meanwhile, after my last post I did some exploring and found out that I can edit the X-Plane object file in a text program such as Notepad so that the surface of the object is shiny. I tried it, and by golly it works!
But I'll keep your info in mind for future reference when and if I have a need to use a rendering program. By the way, I chose to look into Kerkythea because, being of Scot ancestry, I'm naturally attracted to free programs. However, my impression is that there's a long and steep learning curve with that program.
Have a great day,
Bill