If you just want to make a smoothed version of the initial Voronoi cells, then you could skip the whole simulation part like this:
voronoi_cage.gh (10.7 KB)
If you do want to simulate though, there is a new soft-body collision component in the latest R7 SRC that makes it a bit easier. This will give a more realistic squeezing together of the balloons. When you let them move around freely like this, the gaps between them no longer follow the original Voronoi division.
balloonpack.gh (16.2 KB)
and here’s another example with the soft-body collision:
ballooncollapse.gh (23.2 KB)