My apologies for not seraching the threads first. I found AJP's site. Thank you.
Aside from AJP's scatterplot rotation matrix trick, are there any add-ons for true 3d scatterplot functionality?
I just did a google search on 'excel 3d scatter chart addin, and while
the regular search results weren't too interesting, the list of
sponsored links down the right edge of the page might help, if you're
willing to buy a solution.