RBD Clustering, an "update"

Instead of using the cluster attribute found in Sam's notes...

Add a primitve VOP to your constraint primitives.
Create a voronoi noise and promote the frequency to the top level.
Plug the output (dist1 is good) into a ramp float node and then mess around with the curve to create some interesting patterns (try adding noise to this), which will essentially operate as clusters.. Export this to Strength, or multiply it by a pre-existing value.