Hi Lang,

> So if I generate the seam curve (which came from the original curve that made the
> dome and was twisted) but say scale it so it sits on the outside a little would that sort it?

It can often help to do that, but in your case here the fillet still gets confused in the top area where you've got both a tight bend in the edge to be filleted and also the scoop comes close to being tangent to the dome. The fillet that is generated right in that top area is malformed and does not hug the surfaces which is why it's having problems with the trimming part.

It's probably possible to use the fillet surfaces that were generated to get most of it in place by trimming other areas of the dome with the fillet other than that little piece in the tip where it was mangled. Then there will be a small hole that you'd have to patch in using some other surface construction technique like doing a sweep there. Do you want me to try to do that? Or does Stefan's already finished filleted results above from ViaCAD give you what you needed here already?

- Michael