I thinkto archieve this with your Geometry will be a little bit difficult as it is twisted, it will probably fail everytime there to create a closed mesh
I just tried the definition you posted and it worked on the pipes!
however, I draws only 2D Voronoi. I need 3D (interior cells) not only on the surface of the pipe. (I dont want it to be hollow)
Thank you for your reply. It seems the voronoi is only happening on the outer surface though. The original aim I think was to have the voronoi going inside the volume as well. So that multi-pipe could then be applied to it.