SoftParticles, based on his code: http://www.joeforte.net/projects/soft-particles/
Requires using float texture (I didnt make a check if it is unavailable, but has to do).
I made SoftParticlesProcessor and adding it to the viewport and using “Shaders/SoftParticle.j3md” instead of “Common/MatDefs/Misc/Particle.j3md”
will render them differently.
Code rar can be found at http://haima.dy.fi/jme and go to files dir. Can’t hotlink files!
http://img35.imageshack.us/img35/1629/softq.jpg
(left image using soft particles, right does not)