Manually select particles you want to remove (because of collision error)

[pastor]

Hello everybody!

My goal is to fill a hourglass with coffee beans

the problem is I have collisions errors, some coffee beans (1%) are going throught the glass

So I know there are a lot of parameters in main tyflow side panel : Simulation tab like substeps , pos iterations and Vel iterations but solving the problem by this way takes a lot more of cpu time. although it improves things there is one or particles that remain annoying.

Is  there a way to get rid of some particles that are at the wrong place (collision errors) manually ? I mean a kind of "edit poly modifier" you could apply on the  particle group you choose and then you can choose the specific particle you want to remove ?

Thx

[d4rk3lf]

Make a box (or any other object) that you want to kill them.
Add an surface test operator - pick your "kill object", adjust the distance parameter to your liking.
Wire that operator to second event that only have delete operator.

And there you have it Every object that is close enough (by the distance parameter) to the kill object will be deleted.

[pastor]

Make a box (or any other object) that you want to kill them.
Add an surface test operator - pick your "kill object", adjust  the distance parameter to your liking.
Wire that operator to second event that only have delete operator.

And there you have it Every object that is close enough (by the distance parameter) to the kill object will be deleted.

Thank you very much d4rk3lf for your help !

It solved my problem ! but first It tooks me time to figure :

1/ the surface test object was a kind of lathe with a cavity and it didn't work, until I cutted the object in 2 half and assigned both of them in the surface test.
2/ the accuracy had to be boosted from 1 to 5

So now it seems to work

But I have other issues :

I know I may abuse, but if you have time, could you have a look on my file ?

https://gofile.io/d/8gnWdN  (3dsmax 2017 and 2020 )

I just want to fill a container with coffee chunks ( I used in the operator SHAPE :  mesh type Chunks (round) may be i have to make first my particles in real geometry ? ) but at the end of the simulation, the particles are still jittering and moving and a lot of particles are interpenetrating and going outside the container

in fact when I see this example made with realflow, it looks rather simple but I think I'm lost in the sea of tyflow parameters
https://www.youtube.com/watch?v=qGLPtGbO...v&index=12

[pastor]

I just figured this in the tyflow manual :

"The total number of evaluations per binding per frame can be calculated as (bind steps) x (simulation time steps). The higher the total number of evaluations, the more accurate the solver results will be. For granular simulations, a simulation time step of either “1⁄4 Frame” or “1⁄8 Frame” with bind solver steps of 5-10 is often adequate. For hires cloth simulations, bind solver steps may need to be much higher in order to maintain cloth stiffness."


so to set the time step in the main settings of tyFlow  form 1 frame to 1/4 frame solve the intersection errors, so I don't need to use the surface test operator anymore.
But I have to set all the others parameters again

[d4rk3lf]

I've already created some scene for other user.
It's not a coffee, but chunks filling the container, but you can replace it with coffee models.
Here it is:
http://forum.tyflow.com/thread-1391.html

Yeah, increasing substeps (both globally and in PhysX) can help make more stable simulations.
But, truth be told, I very rarely use it, because it just work with defaults as it should in most of the cases.
Only if I fracture particles to very small geometry pieces, I probably get some very bad models (2 vertex in space maybe), and then I need to increase sub-steps.

[pastor]

I've already created some scene for other user.
It's not a coffee, but chunks filling the container, but you can replace it with coffee models.
Here it is:
http://forum.tyflow.com/thread-1391.html

Yeah, increasing substeps (both globally and in PhysX) can help make more stable simulations.
But, truth be told, I very rarely use it, because it just work with defaults as it should in most of the cases.
Only if I fracture particles to very small geometry pieces, I probably get some very bad models (2 vertex in space maybe), and then I need to increase sub-steps.

Thanks !!!!


While looking at your example, I figured I used too much operators in my simulation (particule physics , force and mass) so I removed them and the simulation looks faster !

I suppose the Phyx Collision (Mesh) operator is enough to manage the Inter particule collisions ?

But I don't understand why my grain particules are jittering at the end (they are continuously moving at the end of the simulation)
in the Particle Physics operators I removed, it seems that Collision force settings (stiffness / FRiction / Mass z-bias was helping to stabilize the jittering (but it was not perfect)
But in your example, it was not jittering at the end while your settings was pretty untouched

[pastor]

I think I've found what was the setting difference between our 2 simulations:

You boosted the setting "inertia mult" from 0.5 to 10. It seems that it solve the jittering problem at the end of the simulation