I am designing a very rough prototype for a test chamber for a summer internship. I am planning to 3D print this tomorrow morning. I have only been using Rhino for a couple days, so my skills are very limited, but from what little research I’ve done, I know I need the chamber to have watertight edges or no naked edges so that it can be built/printed successfully. The ShowEdges command states I have 6 naked edges, (indicated by white color in pictures below) but I do not know exactly where these naked edges are, even when they highlight them, or what I need to do to fix them. The bottom part of the chamber is hollow, as I need to place something through the bottom. The naked edges seem to be within the tube coming out of the side which will lead to a viewport/flange. Any ideas on what I can do to fix this? Also, what else should I check for before taking this to the shop to print it?