Help to divide surfaces

Hi Guys !
I need your help about GH. I'm working about a project of dynamic public space. So, i just want to divide a surface(1) with "metaball curves"(2) and "curves from radian grid" (3). After i just want to extrude the result surfaces in fonction external data.

I try differents operations but all is wrong, so, can you help me please ? 

1:

(2)

(3)