Michael,

I was basically pushing the envelope with what I could try to do. It's not typical for the work I do but I enjoy playing ;-) I did find out that fillets didn't work either ;-)

The inset I was doing only went down to the line near the top. Sometimes I can take that top part off and it reveals a surface that I can thicken up to create the inset. It looks like the valleys/peaks between squiggle control points can't be less than the thickness (or twice the thickness) of the wall on the inset. And as you said, the depth can go into the funky bend areas or things just go to pieces.

As always, thanks!