Compositing a 3D curve from two planar curves - list nightmare

[Joseph_Oster]

Here is a variation on a slightly different method:

Blending Two Curves

[Blending_Two_Curves_2017Nov9b]Blending_Two_Curves_2017Nov9b.gh (10.6 KB)

3D curve_2021Feb25b.gh (9.1 KB)

It matches well in front view but not top view. I think your curves must meet at one end for these methods to work. P.S. Tested - there’s more to it than that…