Catenary roof structure

Hi all,

I am currently working on a project for the design of the roof of a parking lot.

At first I created a surface with grasshopper and baked this surface into rhino. In rhino I converted the surface to a mesh (NURBS object). The goal is to relax the mesh between the boundary lines (catenary lines) which are the control points. And after that I want to drag the columns down to the floor to create a nice shape.

But when I use the mesh for the Kangaroo plugin, grasshopper and rhino stop working ('not responding'). I think this has something to do with the density of the mesh that is created from the surface. But how am I able to control this?

All the help is welcome,

Thank you in advance