We have very cool and useful feature in the Maya for nParticles.
It's Particles Self Collision feature.
In the Maya it's so fast and without any problem or error.

I know Dynamic System of Houdini is so perfect and in some special cases , it's actually better than Maya , But I think we don't have this feature in the Houdini , even with new Particles System ! Right ?
So how can I do that ?
Specially for sands and soils simulations ?

I don't know what's better way and solutions for now.

But maybe this Topic can help you :

http://forums.odforce.net/topic/8061-inter-particle-collision/ [forums.odforce.net]

Also we have an example project in the Houdini Help about this.
Of course I think in this example we use RigidBodySolver for self collision of the particles , So each particle simulating as different RBD object and I think it's not very fast !!!
Maybe it's good only for learning :wink:

Specially thanks for your Help Sadjad.
It's exactly something that I want , But as you said before , it's really slow !
I wanna do that very fast , because I have too many particles for sands !

You can use popproximity which create nearestdist attribute that can be used to trigger popinteract.

PradeepBarua
You can use popproximity which create nearestdist attribute that can be used to trigger popinteract.

Specially Thanks , Yes , That's another way , But I think it's slow too , maybe slower than using Bullet Engine for particles !

I think Sidefx should add this feature in the new Particle System ! :cry:

also note that the technique in popswithrbdcollision example is old and therefore the slowness
to get particles with rbd collisions in >=H13 you can just use packed rbd's which combines power of particles and bullet and works without any special setup

tamte
also note that the technique in popswithrbdcollision example is old and therefore the slowness
to get particles with rbd collisions in >=H13 you can just use packed rbd's which combines power of particles and bullet and works without any special setup

Really Thanks , But how can I use RBD Pack ?
I should add new particles in the AutoDopNetwork , then use RBD Fractured Objects ?

Check this expample file:
http://www.sidefx.com/docs/houdini13.0/examples/nodes/dop/rbdpackedobject/EmittingObjects [sidefx.com]

PradeepBarua
Check this expample file:
http://www.sidefx.com/docs/houdini13.0/examples/nodes/dop/rbdpackedobject/EmittingObjects [sidefx.com]

Thanks , I saw this help before , But I don't know how can I use it for Particles !?

You need not to use particle. If you see in detail view Packed RBD Object is just single point. Since these are like points so all the popdop nodes work just like particles. The way you use forces and other operations to popdop, same you can use for packed rbd objects too.

If you want to use particles only then check this:

http://vimeo.com/82039752 [vimeo.com]

In the end of video Ari did something similar.

Here is a video by Matthew Puchala.
https://vimeo.com/111449179 [vimeo.com]

May be he can help you more.

Sure, I would love to help. I have been developing a self collision solver that can be implemented as a solver on POPs in DOPs. I am extremely happy with results for simple collisions such as in the first example of my video. My algorithm was designed to handle things such as crowd avoidance, or particle simulations that need volume preservation, and do it quickly. However I recently decided to stress the system under “high density” situations, such as sand or ball bearings in a cup. It dramatically slows down the sim time, and does not preform well at all. From what I observe in testing, my solver does preform the calculations to maintain a rough volume and collide. However, it struggles to find an equilibrium and settle into a rest state. I am still working on it and will post any updates if I get a chance to play with it some more.

Hi everyone,

I know this is a very old post, but I stumbled across it while looking for a solution.

I actually found that giving your points a @pscale attribute (i.e. via POP Wrangle) right after the POP Source and then using the POP Grains Node with the same seperation (i.e. 0.1) gives you a pretty fast way of getting the same effect as with nParticles.
To visualize it just use a POP Sprite (set to sphere_matte.pic).

I may upload a file when I'm home…

Cheers,
Chris

Thanks Chris, that helped me!