PARAMETRIC PARABOLOID / NEWCOMMER

Hello,

I am quite new to Grasshopper and wanted to know if anyone knows or has any tutorials on how to make a parabolic curve (or paraboloid) where one can adjust the position of the focus relative to the vertex and have the curve (or parabolic surface) adjust accordingly.

I have explored this manually in Rhino but wanted to make this Grasshopper.

I have also located a few parabolic equations and wanted to know if there is an option to input these equations that determine the growth rate of the parabola into Grasshopper or is this better done in RhinoScript? If so any tutorials or tips?

Thanks

Obi