Hi Steve, also looking at that shape you've got a pretty tight bend around that brim area particularly in the last one - that will tend to limit the shell or offset thickness to a small value, it should be smaller than the radius of the tightest bend of the initial surface.

Otherwise the result would be a self-intersecting mess.

Here is a bit of illustration on this:



Notice how if we have a distance that is greater than the radius of the bend, it will produce bunching and self-intersection there as it tries to negotiate that bend? That is the kind of thing that can happen with offset and shell (and fillet too).

If you have a tight bend you will generally need to use a rather small offset distance or shell thickness as well.

- Michael