Defines a Curve lying on a Surface by mapping a 2d-Curve to a surface. It contains a surface Mapper and a 2D-Curve Curve2d. The 3D-Curve.value is given by a call to Curve2d.value(t), which gives the parameter u,v. The Value of u and v retrieves the points of a Curve on the surface.

Public static (Shared in Visual Basic) members of this type are
safe for multithreaded operations. Instance members are not guaranteed to be
thread-safe.