... I've done v5 designs, the fill command is strong. My exerience that you have to remove the parameters. It is more a repair command for the case I have a poor model with open edges. In the picture, the orginal faces in your model were removed in the fill area those operations you do not have to forget. Patch or n-side face doesn't work as fine as fill. In Nx , to get a usable result I have used the through curve mesh, in this case I would add guide strings. Its the fill in GSD workbench and the rough offset in GSO V5 are much stronger in V5 but the rest is the same - at all I still prefer NX. The mess is, years(min.6) ago I reported both it at the GTAC, but I was blocked or forgotten on their IR heap. Maybe the haven't compared. Working inside Nx the setback functionality is the best. Working at sheetmodels in both Cad sytems is a lot of experience to solve those problems.