Constructor for the OdGeNurbCurve2d class. 

High degree values make curve more flexible. For example degree 1 is used to define a segment, degree 2 is used to define a nurb circle, etc. 

A knot vector defines a sequence of parameter values that determine where and how the control points affect the curve curve. The knot vector is a sequence of parameter values and divides the parametric space into intervals, usually called knot spans. Values of knot vector must be provided in ascending order, for example: (0, 0, 0, 1, 2, 3, 3, 3) can be valid while (0, 0, 2, 0, 3, 1, 3, 3) cannot be valid. 

The control points specify the placement of the curve and adjust its shape. The quantity of control points must be at least the degree + 1. 

If isPeriodic is false, then knots.length() must equal controlPoints.length() + degree + 1 If isPeriodic is true, then knots.length() must equal controlPoints.length(), the first and last controlPoints must be equal.

OdGeNurbCurve2d Constructor