Non-rectangular details? Change/filet a detail border?

Rhino Rhino for Windows
#1

I have a rectangular detail border. I’d like to give it filleted corners. Filet crv doesn’t seem to work. How do I make no rectangular details? Suggestions?

#2

Hello - see

-Pascal

#3

I had found that. Too much effort. I’d hoped WIP 7 might have something similar to ACLT’s “Viewport from object/polygon.” Oh well.