I started this experiment in order to get me used to the environment of grains in Houdini and also just for fun And it was fun, a little surprise is that at first I manage to get the point so small it was like very thin sand, not really the look i wanted) so (for the first time in my life, I think ) I actually had to dial back on particle number :shock: It felt weird.
But something I notice by this accident is that the clumpiness did not seem translate in smaller particle size sims. When the particle size was small the sand behaved more dry than when it was bigger. I haven't done enough test to check this but it got me wondering about the relation between pSize and clump behavior.
polygon86.86 How to make the sand simulation do not fall off the beginning of the simulation
For that project I think I basically just deactivated gravity and then just added a popforce that only affected those particles with a certain attribute “force*=@myAttribute”. You will need a SOPsolver in your sim to transfer attributes to your original sand element.