Negative space

 Hello,

I was trying to get the negative space of the pipe-like design as you can see in the attached 3ds file (which you can open in Rhino partition%20Bayram%2024Dec.3ds). The pipes are mesh and Boolean mesh difference did not work. I am trying to create the negative space to fill it in with a material in the future.

It will be appreciate it if someone can help.

Regards,,