cloth simulation: infinite movement
#1
Hi everyone!

I have met an issue I can't solve on my own. I try to simulate curtain, using CUDA solver, and it appears that during simulation the cloth desn't want to calm down. It looks like completely weightless, no matter of the gravity. It waves, it streches, it wrinkles, but  never stay still, even on 2000 frame and more.  How do I calm it down so it should just hang for a while without any movement?  Help me please guys! Here are some of my settings. I have highlighed which settings I adjusted.


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.zip   curtain_test2020.zip (Size: 878.58 KB / Downloads: 98)
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#2
Can you post the file?
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#3
can you upload scene?
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#4
Yes, I have added zip file i the head post! Thank you!
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#5
Not sure if i understand, but if i set timing on the Force (turb1+turb2) from 0 - 50 frames it calms down after that and settle with some movement. You want the curtain to get wrinkled/curled up by the turbulence force and then come to a rest?
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#6
(12-06-2021, 04:54 PM)spen Wrote: Not sure if i understand, but if i set timing on the Force (turb1+turb2) from 0 - 50 frames it calms down after that and settle with some movement. You want the curtain to get wrinkled/curled up by the turbulence force and then come to a rest?

Yes friend, seems that this has solved my problem! Never could imagine that this infinite movement was caused by working perlin noise forse...
Thank you very much.

One more question before closing this thread, how to get rid of some unwanted particle sticking between each other?
As you can witness from example, a vertex from left curtain has stuck to the vertex on the opposite half.


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#7
Make sure the cloth has no self-intersections at frame 0...problems like that usually occur if the starting state of the mesh has intersections, which can therefore not be resolved.
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#8
(12-06-2021, 05:40 PM)tyFlow Wrote: Make sure the cloth has no self-intersections at frame 0...problems like that usually occur if the starting state of the mesh has intersections, which can therefore not be resolved.

I checked - none intersections at 0. Each simulation I get random particle sticking - this time two edges of the same cloth Sad


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#9
Can you upload the scene with any modifications you made since your original post? Just want to make sure I'm examining the most recent version if I take a look at it...
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#10
(12-07-2021, 05:04 PM)tyFlow Wrote: Can you upload the scene with any modifications you made since your original post? Just want to make sure I'm examining the most recent version if I take a look at it...

No, it is the same scene I posted already. I had this problems in my every cloth simulation before too. Is it some particle binding issue? I already removed any friction, but still sometimes get this sim error.

P.S. vertex sticking sometimes occure even inside the same mesh, like in example attached.


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#11
Hmm that's odd...I simmed 1000 frames into your scene and didn't see any self-intersections occur. You can check the MAXScript listener while simming...it should report if it wasn't able to get rid of all intersections at the end of a time step.

Dropping the sim timestep is usually a good way to improve collision accuracy. Yours is at 1/2 frame. Try 1/4. When you lower sim timestep you can also lower bind solver iterations. Yours is at 150. At 1/4 timestep, you could try 75 to speed things up.
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#12
(12-09-2021, 06:53 AM)tyFlow Wrote: Hmm that's odd...I simmed 1000 frames into your scene and didn't see any self-intersections occur. You can check the MAXScript listener while simming...it should report if it wasn't able to get rid of all intersections at the end of a time step.

Dropping the sim timestep is usually a good way to improve collision accuracy. Yours is at 1/2 frame. Try 1/4. When you lower sim timestep you can also lower bind solver iterations. Yours is at 150. At 1/4 timestep, you could try 75 to speed things up.

Yes, dropping the sim step along with iterations seems to solve those issues.

Thank you very much for your help!  Awesome plugin!
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