How can I draw line tangent two curves on a surface?

V4 V5

I have a circle and a curve both of which are projections on the surface. I need a line also following the surface tangent to these two.

How is that done ?

Also how can I use curve drawing tools on a surface ?


Can you share the example file?

Like to do what?
There’s the OnSrf object snap and the InterpCrvOnSrf command. Check the Help.