Dear Dale,

I have a question about the NURBS algorithm implemented in Rhino and @DavidRutten recommended me to ask you.

I tried to create a simple quarter circle in Grasshopper using the NurbsCurve module, but I didn’t succeed. This simple example can be found in many books (e.g. The NURBS Book written by Piegl&Tiller):

we have three control points:

{1,0,0}

{1,1,0}

{0,1,0}

three weights:

1

1/sqrt(2)

1

and the following knot vector:

{0,0,0,1,1,1}

Unfortunately I always get an error message from NurbsCurve, that it can’t calculate the curve.

Could you please tell me which NURBS algorithm is implemented in Rhino (e.g. deBoor) and how could I solve the problem?

I really appreciate any help you can provide.

Gabor