Michael,

Your revised separateOBJ.exe works well. It allowed me to assign multiple materials in HyperShot Renderer to my single object created in MoI

I made no attempt to optimize materials or lighting , or reproduce a real object - This was just a test to see if I could assign materials to different sections of my existing simple model.

For people new to modeling like me, here is my workflow:

Create ring 2D profile in CorelDraw, save as EPS and import into MoI (or create 2D profile directly in MoI as well).
Sweep profile around circle path in MoI to create ring.
Save as .obj file.
Run Michael’s program: separateOBJ.exe
separateOBJ.exe breaks ring object into 4 sections along sharp edges and assigns a material to each.
Open HyperShot and import object.
Assign an environment and backplate image from menus.
Assign a different material to each of three sections of ring object.
Render updates in just a few seconds.
Save screenshot jpg image.
Crop and reduce jpg image in PaintShopPro.

Ed