The collision doesn’t work well

Omniverse Archive Samples & Examples
22

Did you modify the scene before pressing play? The cause of the problem is that there is a missing Cube in the scene, I have tried the demo on my end it works fine, the error in the log is this:

2022-11-19 08:24:49 [311,287ms] [Error] [omni.physx.tensors.plugin] Pattern '/World/Box/Xform/Cube_02' did not match any rigid bodies

2022-11-19 08:24:49 [311,287ms] [Error] [carb.physx.python] AttributeError: 'NoneType' object has no attribute 'count'

At:
  c:\users\asupa\appdata\local\ov\pkg\create-2022.3.0\kit\extsphysics\omni.physics.tensors-104.0.4-5.1\omni\physics\tensors\impl\api.py(778): count
  c:\users\asupa\appdata\local\ov\pkg\create-2022.3.0\kit\extsphysics\omni.physx.demos-104.0.4-5.1\omni\physxdemos\scenes\FluidIsosurfaceGlassBoxDemo.py(249): on_tensor_start
  c:\users\asupa\appdata\local\ov\pkg\create-2022.3.0\kit\extsphysics\omni.physx.demos-104.0.4-5.1\omni\physxdemos\__init__.py(1089): _can_callback_physics_step
  c:\users\asupa\appdata\local\ov\pkg\create-2022.3.0\kit\extsphysics\omni.physx.demos-104.0.4-5.1\omni\physxdemos\__init__.py(1103): _on_physics_step

2022-11-19 08:24:51 [313,867ms] [Error] [carb.events.python] RuntimeError: Accessed invalid expired 'Cube' prim </World/Box/Xform/Cube_02>

Looks like you might have deleted the Box prims? That would cause this issue.

24

I created a sphere as a vessel instead of a cube. I don’t know why the software shuts down. What is wrong with this? Personally I think it is the lack of vram. If so, is there any solution?

kit_20221203_092106.log (1.3 MB)
aaaaaaa.usd (5.8 MB)

25

Yes, looks like you are running out of memory, you should reduce the number of particles.
Before you load that stage for Fluid isosurface, press the Open Source button, there you will see where this file lives.
Then open that file in some editor and change the number of particles generated, should be this function (the 110 and 65 numbers, or change the spacing above to be more sparse):

        positions, velocities = particleUtils.create_particles_grid(
            lower, particleSpacing + 0.01, 110, 65, numParticlesZ
        )
26

I see. After I load that stage for Fluid isosurface , Is there any way to change it?

27

Not in the UI, you can modify the UsdGeomPoints in a python script

29

Some water penetrates the sphere, what should I do?
2022-12-10 12-57-33.mkv (9.4 MB)

wow.usd (1.5 MB)

30

Hello,
You can try to enable CCD on the Particle System (that doesn’t help much in this case unfortunately), and you can try to increase the “Rest Offset” under the advanced properties of the Particle System. Make sure to have “Contact Offset” be about 1.5 times larger than “Rest Offset”. For me 1.0 and 1.2 worked in your scene with the non-moving sphere. If you don’t like the gap this creates between the rendering of the sphere and where particles collide, you can use a different sphere for gfx.

31

What does it mean “gfx”?

32

Graphics (you can use a different sphere for rendering)

33

I am sorry I am beginner and I am not good at English so I can’t understand well what you say.

It’s mean I make two spheres like rendering one and simulating one. If so how can I match them.

34

You can create xform then under this xform you put two spheres. One for rendering and the other for physics.
The one sphere that you want to collide against you add collisions and set its purpose to guide in the properties panel or make it invisible. Then you can move with the xform and you move both physics and rendering.