Hi Michael,

> Maybe I'm doing something totally wrong.
> So whats the best or correct way to do this kind of operation?

Well, you're not really doing anything wrong other than needing to get the whole thing joined together as one piece.

Sometimes seam curves can tend to get in the way and that's what's happening to you here.

With the pieces all joined together into 1 solid (see attached 3DM file), then fillet looks like it will be able to generate a partial result but it has difficulty trimming the objects back so the fillet piece that gets generated will have to be manually trimmed into place.

Let me know what fillet radius you want and I can help you do that.

Also the one main thing that would probably make it easier is if the midpoint of your shape was actually aligned to the seam instead of shifted just a little ways to one side - is that intentional that your top shape is not symmetrical around the center of the revolve?

By the way it's late over here so I'll probably have to continue tomorrow.

- Michael