Hi Rudy,

The profiles have a different number of control points.
When you do a sweep, MoI sort of drives the profile curves around the rail curve... if the control
points of the profiles don't line up well, the surface breaks up and becomes a polysurface.

I took your top profile (12 o'clock ) and rotated it (with/copy option) to the 6 o'clock position.
and then using scale 1D, I made it the same size as your bottom profile.
Now when doing the sweep, the control points will line up and create a smooth surface.

Sometimes, I like to draw an ellipse or circle, then turn on the control points and by selectively grouping some
control points and then using *align *move* and *scale 1D*, I can shape the ellipse into a half dome for
a ring profile Then if I copy, rotate and scale the profile as a whole, I know all my profiles will have the same number
of control points and make a smooth surface.
I did a variation of the ring by offsetting the finger circle, shaping it the way I described above, and then a 2 rail sweep.

The advantage of a 2 rail sweep is that you can control the wall thickness of the shank at the sides where
it tends to balloon out with a 2 profile, one rail sweep. You could also put profiles at the 3 and 9 o'clock position
to control the wall thickness, but usually, the fewer curves that you use to accomplish the design, the better.
I hope this makes sense..Michael will be able to explain it better. :-)

Jesse