So - working with a circle and an ellipse to begin working out the particulars,
it's apparent that the inside and outside curves in the xz plane are going to be
offset curves. (and so they rear their heads _again_!)
I don't know if those curves are themselves ellipses or not.

And that may factor into how difficult it is to derive an equation for the
desired surface.

I feel some 3D diagrams coming...

Post a reply to this message