Hi Michael
Thank you very much for the replies.
I used Sweep because I needed scaling rail to make the shape more consistant as to the thickness (along y-axis)
In Rail Revolve the tips are a lot thiner (along y-axis)

This the one of several petals of a flower thus is it of world coordinates
I am trying to draw jewelry pieces with MOI and Rhino. Some are very organic. I have tried various programm and ZBrush in addition to MOI and Rhino does pretty much all I expect

Could you please advice on how to use Cplane in MOI? This petal I think could be something to learn Cplane in MOI if it works in MOI

Thanks
Olga