This .NET class wraps the AcGeCubicSplineCurve2d ObjectARX class. This class represent an interpolation cubic spline in 2D space.

Autodesk.AutoCAD.Geometry.Entity2d
    Autodesk.AutoCAD.Geometry.Curve2d
        Autodesk.AutoCAD.Geometry.SplineEntity2d
            Autodesk.AutoCAD.Geometry.CubicSplineCurve2d

Public sealed Class CubicSplineCurve2d
Inherits SplineEntity2d

public sealed class CubicSplineCurve2d : SplineEntity2d;