I have been trying to form a solid from a bunch of surfaces in SW and I ran into some problems. I made offset surfaces from my initial STL file and then knitted different portions together. Then I try to do one final knitting by connecting all the sub-knit surfaces to form a solid. However, I noticed the "try to form a solid" option is inactive. I defined new off-set surfaces from the tiny chips the gap control window identified and rebuilt the knitted surfaces. Still, I don't seem to be able to form the solid. Only when I disable the gap control option, the "try to form a solid" option becomes activated which is great but when I hit Okay, it apparently doesn't make the solid body yet. The way I verify this is through making an extrude cut hole in the object. When the object is still a hollow shell, I'm not able to make that hole (tunnel) inside the body. I spent a lot of time on this and it's getting kinda frustrating now :-/..so I would appreciate it if you SW experts out there could make a comment on this or see what I am doing wrong in the attached file. thank a lot in advance for your help!