I am using the Nurbs definition of Wikipedia. I might have missed something in the definition but I cannot understand how to know on which interval does the parametric coordinate span. Particularily for an unclamped knot vector. It seems that it is not the first knot vector value and the last knot vector value that defines the intervals for any Nurbs. So what is the rule if there is one?
For a NURBS curve with a given knot vector, the following rules are always true:
- the number of knots = the number of control points + degree + 1.
- the parametric range is always defined between knots[degree] to knots[number_of_control_points] where knots starts from index 0. This is true for all knot vectors, clamped or not.