Hi Pat,

In the beginning I too was a bit confused by all of this talk of "mesh".
For Jewellers wanting to export a design to be milled, an STL file is the "mesh" that we'd use.

But to do a realistic render of that jewellery piece, you'd need to use a different kind of "mesh" to suit those programs.
From what I understand it appears that for rendering, you'd use an OBJ file as that "mesh".

Hope this helps, Colin