Snapping Curve to a Surface/Polysurface

So Osnap has some hidden options when you hover over it while holding either Ctrl or Shift you get different options. I want to snap a polyline/InterpCrv on a surface but it seems like you have to start the command then hover over the Osnap while holding Ctrl and manually select the option to snap to a surface, polysurface, or mesh. Is there a faster way to access these options or constantly have them on and turn them off/on as needed with a check box similarly to the check box options for Osnap (End, Near, Point, Etc.). Or can they be written into a macro or hotkey?

Hi Tommy - OnSrf , PersistentOnSrf (lasts for the duration of a command - might be what you need) are ‘one shot’ osnaps where in general it does not make sense to just have them ‘on’ all the time. You may be able to smooth things out with a macro like

! _Polyline _PersistentOnSrf


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Thanks Pascal, I didn’t know you could use the PersistentOnSrf option in a macro. This will work perfectly for me.

You can also try this great plug-in for drawing an editable curve on surface:

rhino6curveonsurface.rhp (166 KB)
! _CurveOnSurface
! _CurveOnSurfacePtOn
Curve on surface