If it isn't obvious after a single pass, it can be fastest to simply
delete the offending shell and carefully re-do that shell's geometries.
Some problems are better left unsolved when you have a tight deadline
;-).

~Nick

Nick Caton, P.E.

Senior Energy Engineer
Energy and Sustainability Services
Schneider Electric

D 913.564.6361
M 785.410.3317
E nicholas.caton at schneider-electric.com

F 913.564.6380

15200 Santa Fe Trail Drive
Suite 204
Lenexa, KS 66219
United States