Offset Civil 3D Surface

I have been through the example provided here and think i have replicated the same thing however when i run the script it stops at Surface.Offset and says gap cannot be filled.

Any help on why would be much appreciated. I don’t think i can upload the dynamo file as i’m a new account.

Pinging the original author @marshmallow

Hi @craig.robertson, could you post the drawing to take a look?

Hi, I can’t upload so unable to post it. Is there another way to send the Dynamo file?

Thanks, never knew about this, do you know if this works for .dyn files as the one i uploaded won’t allow me to copy the link.