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Gas Sand Forces Microsolver

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Hey Guys,

I've recently had to investigate simulating sand.

I've manage to find a work around by combining a few different techniques which seem to work for the shot, however i came across the Gas Sand Forces Micro solver and would love to know how to implement it.

I don't know if the micro solver will do what i want, I'm doubtful that it will.

Either way i would love to know:

A ) What it was designed/used for ?

B ) How it can be implemented ?

I'm hopeful that it plays well with the Flip Solver, although I have a feeling that its something left over from the old "sand" solver, that the the new Flip solver is based off and it being legacy...

Any insight would be great!


Edited by garciaone

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Hi Beau,

As far as I'm concerned its a legacy node.

Dneg used Houdini to simulate sand in John Carter, but they developed a custom solver for that.

It has been awhile since I played around with the idea of simulating sand. The most important difference between sand and water is that sand stacks. The basic idea is that the a pile of single sand grains don't push each other down, where water does. Or water has column pressure where sand doesn't.

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Hey Nick,

I'm aware of the solver used on John Carter and the stackable nature of sand ....I'm more interested in the micro solver in question and I'm also curious about how micro solvers like this should be implemented?

I've got a setup which meets the needs of the shot, but I'm curious for my own knowledge about this.

I think you could be right about it being legacy though...

Thanks for the reply! :)

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Hi, Did you ever figure out out to use the Gas Sand Forces Microsolver? I'm trying it out with flip, but I don't really know what I'm doing. I'm new to dops so I don't really understand how plugging in microsolvers works. It's not the logical linear workflow of sops. It just seems like if everything is connected with a merge it magically works. I wonder if you can turn off the pressure solve to get the sand to stack?

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It's quite slow and not very good. Might work for some setups, but will definitely not be enough for others. I tried hard to figure the correct setup out by myself and failed - I contacted support and received a sample hip from them. (I can try and see if I still have it somewhere.)

According to the PBD topic something much better seems to be on the way..

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The sand forces micro solver was part of the sand solver

You can still use the sand solver but it has been depreciated, so to reveal it - type 'opunhide Dop sandsolver' into the textport

Maybe you will want 'opunhide Dop sandobject' as well.


I'm not quite sure how it should behave, but here are some sands falling on the ground I got to work.



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