Fits a 2D data with a 2D parametrized function f_2D(x, y ;lp, gp). The slice at y1 is fit using the local parameters lp1, the global parameters gp, and the function f_1D(x; y1, lp1, gp).

When you add a Polygon2D node and select it, you will see a custom area on the right side of the 2D workspace where you can select basic shapes and set parameters ... ShapePoints is a GDScript static ...