Connecting Vertices on a Surfaces with Curves

[Joseph_Oster]

Flatten input to Loft (white group):

Or study the model I posted six hours ago more carefully:

Boundary Surface component not working in Grasshopper

This doesn’t replicate all the details of your model but it does show a “Grasshopper way” of modeling a similar tower. [Version5_2020Feb28a] Version5_2020Feb28a.gh (28.2 KB) [Version5_2020Feb28b] Version5_2020Feb28b.gh (28.1 KB)