Branching a curve and surface

Hey Guys,
Can you give me a direction how to approach splitting a surface (or centreline) into different branches so it looks like a tree.
I can draw curves in rhino so I have a base shape but how to connect two brunches in a smooth surface.
I trying to do in Grasshopper so I have more control.

Please see attached image

Thank you

Hello, in case your street network is planar and a closed curve you can use Boundary Surface. If not this will be difficult (not impossible) to do with Grasshopper.

Yep, It is what I thought as well. Will use just Rhino