Slit a surface which had come from a mesh produced by kangaroo

Hello everyone,

I am long time trying to cut a surface I have created with Kangaroo, but using "surface slit" I only get a kind of plane projection. I hope that maybe someone could help me.

Here are the files:
Coppertura-Gravit%C3%A05.gh

Copertura%20Sassuolo.3dm

Thanks in advance