Need help with curves on surface

How can I make more controlled curves on my surfaces? I want to make curves just like the example below

Looks like you need to draw your curves seperately, then use _Project, or just use the curves to trim the surface…

Also:

InterpCrvOnSrf command

CurveOnSurface command Needs to downloaded and installed http://v5.rhino3d.com/group/rhino-5-labs