Does the image on the left show an assy or part?
If it's a part, then it's the lip that's preventing the "Rip".
Sheet Metal parts must have a common thickness.
It's a PART that has been SHELLED... aka uniform thickness. Left is the whole part... Right is just one corner. I couldn't get a RIP to work on even just the inside "step".
Windows XP / Wireless Intellimouse Explorer
SolidWorks 2007 SP1.0 / SpaceBall 5000 Lava Lamp www.Tate3d.com