Thank you Michael for video answers. Its always easier to see and analyze the process then read about it.
Yes the construction line approach is easiest one but its not universal. That's why i place sphere in that position ;)
Due xsi plugin development experience i always use one final performance test. I tried all my tools on a sphere divided x6.
It's a pretty heavy object. So i totally agree raycast and closest point calculation in a loop or callback may be pretty expensive.
I guess i just expect some kind of cad miracle for that case but it's not always available.

PILOU, the approach in post 9136.21 is handy. But it also need additional manipulation to place it right along Y axis plane.