Hi Danny, another way to think of it is that inset tries to maintain a kind of constant "wall thickness".

If it did a straight extrusion in your case, that would lead to an inconsistent thickness with respect to the chamfer surface. I guess you would like for it to pretend that chamfer was not actually there at all and instead focus on maintaining thickness with the rest of the cylinder, but MoI does not know how to ignore some feature surfaces like that.

I guess what you might want to do is adjust the order of your operations - do the inset first on the plain cylinder and then add the chamfer after that instead of pre-chamfering it.

- Michael