Problem with Recursion


I am trying to do recursion with anemone to extrude a certain number of faces of a wall slab. I faces problem when i tried to cap the mesh. It gives me an error stating that “Object reference not set to an instance of an object”.

But the problem seems to occur since I clean the mesh.

Everything seems working normally up till I offset the selected faces and merge it with the original meshes.

Please find the rhino file and gh script in the attachment.

Thank you.

A4_TLam 20190317.3dm (16.2 MB) (47.2 KB)