Scripts/Surfaces/DevSrf

https://wiki.mcneel.com/_media/legacy/en/devsrf.png

The DevSrf command displays the developable ruling lines between pairs of rails.

The ruling display updates as you edit the rails so you can see when you have a shape that is a developable surface. A dialog box controls the display of developable surface ruling lines between pairs of rails.

The ruling lines are found where the tangents at the ends of the ruling lines are coplanar within a twist tolerance, which means the surface normals at the ends of a given ruling are also parallel.

Ruling lines between more than one pair of rails may be displayed at the same time.

Use Case and Instruction
Useful for designing boat hulls. See youtube video on how to use this command:



Sources: More info about this command can be found here: Rhino Labs