Hello...a couple of my students are designing a hull for a boat for a local competition and they have encountered an error while using the Shell command. Please see attached. I have alttached Inventor part. We are using Inventor Pro 2013 version. Specifically they need the top or deck of the boat shelled out to a thickness of 1/8" for all sides of the hull to create an open-hulled form. But, as I said earlier, the Shell command is giving the attached error. We do not know which vertex is causing the problem. Can anyone please help?