Hi Ryan, this is not really a great way to build a model in MoI, NURBS modelers do not expect to be dealing with a whole bunch of separate little facet pieces especially ones that are only at slight angles to one another.

So to get good quality geometry in MoI you would likely need to reconstruct much of this rather than trying to use the model directly as-is, as far as NURBS geometry goes this type of faceted structure is not a good type of geometry to have, if you want to do further operations on it such as filleting especially.

But really the main problem with naked edges seems to be from duplicated faces, there are several facets that are stacked up directly on top of each other with some of their edges joined to their duplicates. The duplicates will need to be removed first before you will be able to make a clean joined structure.

To do that, start by selecting and hiding the top part which is a separate piece, work on only one visible piece at a time. Then take the bottom piece and run Edit > Separate on it to break it into individual surfaces. Go around the model and one by one select a face and delete it and see if you can see through the model or not. If you don't see any change after the delete you just deleted a duplicate and try again on the same spot to see if there is another duplicate as well. If you see through the model then there was not a duplicate there and do undo and go on to the next face.

Or the other thing you can do is to do one click on each face to build up a selection of just single faces and then invert the selection and delete the remaining ones. This may be a bit tricky since the display can get confused between which of the duplicates is showing on any given screen draw.

At any rate it's the stacked up duplicate faces that is making it not be joined up properly.

- Michael