Gil,
I had the arches working, experimenting with different effects. Was playing with sliders, left them in a poor location. Copied that effect to megatree to see if it worked. Then saved for the night. Problem duplicated. Since nothing was wrong with pixel assignments, I happened to look closer at effect and slider was in a position that illuminated no pixels. Sorry to waste peoples time for such a trivial mistake on my part.
I have been meticulously following the manual. Confusing part for me a newbie, was the model part. I think I have a pretty good handle on that now, after watching tons of videos.
Thanks for your interest and help.