OK, well I finally tried to play with this new feature today thanks to a customer question. (Thanks John)
He and I were BOTH having the same issue making it work. We could change the wood color of the SKIN, but not CORE and could not assign thickness of either. He had gotten it to work on another computer, but not his second computer.
Reason: You must have a graphics card that has OPEN GL version 2.1 or higher.
(This is also the reason some people can't use the Lithophane viewer...myself included.)
I just really don't want to give up my XP.