Grasshopper Sofistik dome creation

Hi all,

I am working on Grasshopper Sofistik workflow for my thesis, where I want to make an FEA of the open-top dome.
I have managed to make a structural area from the dome brep, but when I connect it to the SofiMSHC module, I get an error saying:

1. A given Surface is closed in one direction.
Such surfaces cannot be handled by SOFiMSHC and need to be split.

Anyone has any idea what that would mean and how to solve it?

Thank you,