As Wolf said, he was a model maker, but more than that, he was a classically trained artist, a painter and a sculptor as well as a model maker. He sculpted figures for Valiant Miniatures, who are still in business and Shep's figures are still for sale. He also sculpted figures for his own dioramas, and as one-of-a-kind pieces for commission or for his own enjoyment.
Shep was a member and former president of the Military Miniature Society of Illinois, who developed the Open System of judging shows (gold-silver-bronze, as an exhibitor may deserve, instead of 1st, 2nd, or 3rd and that's it, as in IPMS awards). He was the first Grand Master named by the Miniature Figure Collectors of America.
Shep wrote books on building dioramas and painting figures, and many modelers were introduced to the idea of building dioramas to feature their models, through a series of brochures Shep wrote for dioramas he built for Monogram Models. He promoted the idea that the techniques were available to every modeler, including scratchbuilding and super-detailing (there wasn't really aftermarket till around the 90s), but also groundwork, planning out the scene, pitfalls to avoid.
You can see the Monogram dioramas here:
http://sheperdpaine.atspace.com/
and his books are still published by Kalmbach Publishing. I think they're better than what's published today, really.
Shep also pioneered the art of the box diorama, and many of his pieces, while in private collections, can be seen here:
https://www.boxdioramas.com/sheperd-paine
I'm in the MFCA, and we had a retrospective of his work, as it turned out, the year before he passed away. Shep was active at our show right up till he passed, and it was an honor and a pleasure to get to visit with him.
Your improvisation to address the open space reminded me of Shep's advice about staging a diorama.
