Creating Rail Curves from Mesh

Hi there,

I'm a beginner at Rhino, I'm attempting to replicate Hadid's "Arum Installation" as shown below:

https://vimeo.com/48566063

I get stuck at the point where they say they "rail curve" the mesh - I tried just triangulating the mesh using WB, but then I find out how to smooth the mesh points to get that undulating pattern. Would anyone please be able to give me a hand? I'm merely just looking for the form. I've attached the Rhino file, image of my mesh so far and the definition.

Thanks a lot for your help guys, much appreciated!