View Full Version : Nparticle sim unstable

03 March 2012, 02:12 AM
Hello everyone, I have been having problems with an nparticle simulation working fine for about 40 frames, then it explodes and particles fly everywhere. I am wondering what is the best way to keep this contained and behaving correctly? More substeps in the nucleus? Substeps in the ncache options? Thanks for any help as this project is on a deadline! :)

03 March 2012, 07:15 AM
I'd try to increase the Max Collision Iterations first or generally having more than substeps, because they're not as much a performance hit as increasing the substeps.

More info here

What happens during these frames? I'm sure there's a simple reason for this behavior :)

03 March 2012, 12:51 PM
It is 53 frames of someone sliding along the ground. the first 40 work fine, then it explodes. Which is strange, because he is actually slowing down and almost stopped at the time the sim explodes, it's not like there's some crazy action that starts right there. I have set another sim caching overnight so I will let you know when I am able to check it. Thank you very much for the info so far!

03 March 2012, 02:48 PM
No good on the sim. I will try to increase the max collision iterations like you suggest

03 March 2012, 11:48 PM
I'm guessing that you are using liquid simulation, in which case high incompressibility and/or surface tension can make it unstable, in which case you might try lowering these values. Emitting in collision or overlap can also cause instability with the liquid model. Emission overlap pruning may help, although this won't avoid emitting into a surface.

Or it could be pressure from particles squished together. Lowering the collideStrength may help... with lower values the collision is more like a repulsive force and is less likely to cause instability when it can't be resolved.

03 March 2012, 12:36 AM
Thanks very much Duncan! I will give that a shot.

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03 March 2012, 12:36 AM
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