Polysurface doesn't cap

inner bowl.3dm (283.1 KB)

I checked all steps in https://wiki.mcneel.com/rhino/capproblems, but can’t pinpoint the problem. Can anybody explain what I’m doing wrong? I spend 2 hours trying to find the problem, but I’m not getting anywhere.

Hm - Cap works here… but leaves nakeds…
Your surfaces are bowties, and duplicated in the polysurface…
image

try Revolve on just the arc for one half.
image

-Pascal

thank you.