Performance issues on PhysX Collision scene

[Robin]

Hi,

i have a problem with a simple PhysX simulation, performance is really slow and i can`t find a way to fix it.
I`m not super experienced in working with tyflow, so sorry for any stupid questions.
Scene consists of 3 surfaces, from which the paricles ( small fragments of granulat ) are spawn and they collide with within a surrounding bowl and come to rest.
Attached is a simpls 3dsmax scene, anyone with an idea why the the simulation speed is so slow ?
Simulation is getting slower and slower the longer it goes, after 150 frames it takes around 20 Sek. / frame and calculation time is increasing further.
Have a quite high performance workstation, so there should be now performance issues from the hardware side.

AMD 7950X 3D
128 GB RAM
Nvidia RTX 3090
3dsmax 2024

Also unsure whta is the best option to save the simulation once it is finished and i save the max scene.
Is there an option so once i reopen the scene, the simulation is still calculated and i don`t have to simulate it again.
Only way i found is to export it through an event "Export Particels"  and reload it through tycache object without further editing possibilities.

thanks for help

Robin

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[tyFlow]

You have your PhysX substeps set to 60, and simulation substeps set to 1/4. Given that you have thousands of particles, this is why it's slow.

Set PhysX substeps to something more like 8-10. If collisions are getting missed you can turn on CCD for more accurate collision handling, or even better - create proxy mesh(es) of your collision geometry that are convex, and use them as convex colliders in your PhysX Collision operator instead. Mesh collisions are slower and less accurate (but can be concave).

Also, you have PhysX CUDA enabled in your GPU settings, but CUDA performance won't usually overtake CPU performance until you reach much larger amounts of particles (like, 50-100k+). It may actually run slower on the GPU with so few particles. You'll have to test this on your particular hardware, though.

[Robin]

Thanks for ypur quick reply and suggested settings, will give it a try.