I can not "splop" on round surface

Hi all,
I try to “splop” on a round surface without success. Surface direction is ok. On other type of surfaces i have no problems. Whats wrong?

It is because of singularity at the end of seam (thicker isocurve).
Draw a sphere or an ellipsoid and try to splop away from the seam and its ends.
If you use OrientOnSrf instead of Splop, with History (activated before the command) and Copy option, you will be able to deform the surface and/or the original object and get instat update of the oriented object.

Thanks Mikolay,
sphere metod works!

I try to repeat this old slop tutorial without success https://www.youtube.com/watch?v=1h2ounpIj3s
Some bug? It is impossible to slop or OrientOnSrf on every rail revolved surface i do…