The "import shading only" option requires that the imported file was previously saved from Studio‚Ñ¢ or Designer‚Ñ¢, using either the "export as separate faces" or "export as complete objects" options---and that the file is being imported into the original.
(fewer triangles)
(more triangles)
Better
Worse
Patch-based objects are converted to facets (triangles). More facets means higher surface fidelity but higher memory requirements.