first test with moi of torolf

 From:  Frenchy Pilou (PILOU) 19 Dec 2010  (48 of 56) 
539.48 
maybe after the Offset
Select all internal curves
use Key Tab
then write Rebuild (Enter)
By Points 4 or more
With
Disable Keep corners
& Erase input Objects

EDITED: 19 Dec 2010 by PILOU
Attachments:
Attachmentvoro.jpg