3D Voronoi Bubbles

Hello to all!

I´m new to Grasshopper and am trying to generate some bubbles with different diameters based on a 3d Voronoi, but I  dont get any sense of a soultion.. could anyone help me?

it should look basically like this:

http://www.grasshopper3d.com/photo/zellstruktur-w-rfel?context=albu...