Hi 3image, I've attached an updated 3DM file where I've tuned it up by untrimming things, and then moving your diagonal cutting line over so it matches exactly with the other ends, it was off by about 0.02 units before.

But this will still not offset or shell well in MoI though because it's got one of those "diverging vertices" that I was talking about before, in this spot here one vertex on the original object matches to 2 vertices on the offsetted result, but unfortunately that is not accounted for by the geometry library that MoI currently uses:



- Michael