Need to convert a mesh or polysurface into a single surface

Hi all,

I working from a scan of a foot (in mesh) and the aim is to cut this scan in different parts and flat them to make my 2D pattern (the idea is to create a shoe with piece of fabric)

There is the scan of my foot :

I’ve cuted and divided my mesh in different parts and use the command “quadremesh” to make it clean.
Here is the result :

After this, I’ve convert the mesh into NURBS with the command “inNurbs” :

The issue is that I can’t unroll because its a poly surface, I would like to convert it into a surface. Ive tried with merge, surface network but it’s not always working.
So I need to use grasshopper to make it work but can’t find the nodes map to make it work.
Any idea how to turn this part in poly surface into a single surface ?

Thank you in advance !