Hi Roberto,
As per my understanding you want to work on rational splines specifically NURBS.
You can refer to the below documentation which discusses on construction and working with rational splines.
For specific rational spline NURBS I found an exciting resource on file exchange called NURBS Toolbox which you can utilize for various operations on NURBS and you can also use it for the visualization purpose too.
I hpoe this helps you to proceed ahead with your workflow.
