Yes, Mr. Gibson, I'm good now. Thanks again.

The piece of this model started life as part of a VRML file. I used Rhino to convert it to a series of lines, then used Rhino's mesh to polysurface command, then saved that as a 3DM file and used MoI for cleanup and enhancements.

So, it was probably related to the Rhino polysurface command. Or was it polymesh? Can't remember.