"""""""""I look at this picture and can not understand what you sweep and than how you make thiss mirorred object.""""""""""

Looks like a good candidate for "rail revolve". Mirror the bottom rail and join it, then do a rail revolve on the arc, setting the bottom as the rail. No need to sweep and mirror and construct.

Hi Andrei:

here is an example about "mantain tangency" making a simple bike's saddle.
Both sweep examples (-B-C-) using same splines
Also Burr's suggestion with rail revolve instead of sweep.(magenta line is rail revolve axis)



you can see three different results
have a try with my file attached,if not clear

M

(..oopss..forgive me for grammar error..is MAINTAIN..)

Hi m-dynamics,
thank you good example)