How do you "duplicate" a part from a sub d mesh?

hi i try to find a possibility to do this on rhino. without duplicating and deleting the half is there a way to just copy past for example the half of a sub d mesh ?

Hello - ExtractSrf > Copy=Yes, is what comes to mind.

-Pascal

ctrl+shift select the faces you want to duplicate, then drag with gumball and tap alt to get a copy-

copy