Rhinocommon method question.. please help me

I wanna use a method, “Rhino.Geometry.NurbsSurface.CreateCurveOnSurface”, in ghpython.
Since this method require point2d list, I cannot make curve along with z-direction, vertical curve.

I don’t know how to use this method. Please help me out.

If you use CurveOnSurface method on a complex surface it would create a complex nurbs curve even if you use 2 (UV) points.
The points you use are probably way less than the control points the generated curve will have.
If you want to give a “Z” value (that will became the normal when on surface) you can do it in 2 way:

  • do your curveonsurface with UV points, divide the generated curve and move (normal to surface) those points with your “Z” values (interpolated), and then interpolate again through those points.
  • make your curve with xyz points and then “flow along surface”

Thank you for your reply.
However, I wanna use CreateCurveOnSurface methon in Rhinocommon language.Also, I need z-direction curves on a planar surface which stands vertically. This method requires point2d list as its input so that the curve, I made on surface, is invalid. This is because Point2d cannot has z-value.


If your surface is planar then the interpolation CurveOnSurface would do is the same as a normal interpolated curve.
Use evaluate surface with UV coordinates, then move the created point with the surface normal vector by your Z value, and interpolate through your points.
Do you have some sample data to work on?