jitter after initial state

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andrew pashkov
Posts: 3
Joined: Fri Oct 20, 2017 12:15 am

jitter after initial state

Post by andrew pashkov » Fri Oct 20, 2017 8:36 pm

Hi guys
I am trying to get rid of jitter in my simulation.
First I filled the shell object medium high detail in my volume tag.
Then I run simulation with drag and k-speed deamons to calm it down. Then I cache it
It calms down but jitter still remains and it ruins the picture.
Is there any way to calm particles to avoid jitter?
https://vimeo.com/239167505 - the video sample you can see jitter at the bottom
Thank you in advance
Andrew

Thomas Schlick
Posts: 178
Joined: Tue Aug 29, 2017 12:35 pm

Re: jitter after initial state

Post by Thomas Schlick » Mon Oct 23, 2017 9:14 am

Hi Andrew,

I assume that you're working with "Liquid - PBD" fluids. If this is the case could you please tell me more about your min/max substeps? You can find these setting in the "Scene" object under "Solver". To get better results try to increase substeps to something like 6/8 and you can also set "Accuracy" to 0.8. Maybe it's necessary to go even higher with min/max substeps (12/16, for example). Furthermore it might also help to increase the volume tag's "Surface Offset" (if it's set to "Auto" the value should be OK already).

Please let me know how it went.

Cheers,
Thomas

andrew pashkov
Posts: 3
Joined: Fri Oct 20, 2017 12:15 am

Re: jitter after initial state

Post by andrew pashkov » Mon Oct 23, 2017 10:17 am

Thanks for reply Thomas
I am actually using SHP mode Density 100, Substeps 1/40 Min/max iterations 3/20 Accuracy .2
Cheers
Andrew

Thomas Schlick
Posts: 178
Joined: Tue Aug 29, 2017 12:35 pm

Re: jitter after initial state

Post by Thomas Schlick » Mon Oct 23, 2017 4:28 pm

Thanks Andrew. 40 max substeps for SPH isn't that much and with fluid-object interaction I wouldn't go below 100. 150 may even be better, and if you still observe instabilities I recommend bumping up min substeps to something around 5-10. With SPH accuracy can remain 0.2 - unless the problems won't fix with higher substeps.

The volume tag's shell mode could be responsible for the issues you're seeing. I've made the experience that sharp edges and the shell mode aren't very good friends, but you should really try higher substeps first ;)

Btw, iterations don't have any influence on SPH, but you didn't change them anyway (just for the sake of completeness).

Cheers,
Thomas

andrew pashkov
Posts: 3
Joined: Fri Oct 20, 2017 12:15 am

Re: jitter after initial state

Post by andrew pashkov » Mon Oct 23, 2017 4:35 pm

Thanks a lot Thomas!
Optimal settings is what you dont find easily )
Will try and report the result
Kind regards
Andrew

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