# Impossible to simulate particle system in Isaac Sim during RL training

**URL:** <https://forums.developer.nvidia.com/t/impossible-to-simulate-particle-system-in-isaac-sim-during-rl-training/268610>\
**Category:** Isaac Sim\
**Created:** [October 6, 2023, 10:21am UTC](https://forums.developer.nvidia.com/t/impossible-to-simulate-particle-system-in-isaac-sim-during-rl-training/268610 "2023-10-06T10:21:24Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![bechir.tabia](https://developer.download.nvidia.com/images/forums/profile-default-devtalk-84.png) [@bechir.tabia](https://forums.developer.nvidia.com/u/bechir.tabia)\
**Post date:** [October 6, 2023, 10:21am UTC](https://forums.developer.nvidia.com/t/impossible-to-simulate-particle-system-in-isaac-sim-during-rl-training/268610/1 "2023-10-06T10:21:24Z")

</div>

I am using Isaac Sim included in a Gym env and PPO from Stable Baselines 3

On my environment, I have a particle system coming from a cube mesh processed by a particle sampler. When I run the simulation on the GUI, it works fine. However, when the simulation runs during RL training, it does not simulate at all even though my simulation runs fully on the GPU (see code below). The particle cube does not move of behave like when it is running on the GUI. Does Isaac Sim python API support bulk solids and powder?

 ![Screenshot from 2023-10-06 11-43-31](https://global.discourse-cdn.com/nvidia/original/4X/1/b/7/1b70701d7f2a70d14563699259e203c2f9690dea.jpeg)

```
    #instanciate the world
    self.world = World(
        physics_prim_path = self.env_config["env"]["world"]["physics_prim_path"],
        physics_dt = self._physics_dt,
        rendering_dt = self.rendering_dt,
        stage_units_in_meters = self.env_config["env"]["world"]["stage_unit_in_meters"],
        device = "cuda",
        backend = "torch",
        )
    # set up the physics context
    omni.timeline.get_timeline_interface().play()
    self.physics_context = PhysicsContext(
                            prim_path = self.env_config["env"]["world"]["physics_prim_path"],
                            device = "cuda",
                            backend = "torch",
                            )
    self.physics_context.enable_gpu_dynamics(self.env_config["env"]["world"]["enable_gpu_dynamics"])

    if self.physics_context.use_gpu_pipeline:
        self.physics_context.enable_flatcache(True)
    set_carb_setting(self.world._settings, "/persistent/omnihydra/useSceneGraphInstancing", True)

```

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<div class="post-metadata">

**Author:** ![Milad-Rakhsha](https://developer.download.nvidia.com/images/forums/profile-default-devtalk-84.png) [@Milad-Rakhsha](https://forums.developer.nvidia.com/u/Milad-Rakhsha)\
**Post date:** [October 24, 2023, 8:04pm UTC](https://forums.developer.nvidia.com/t/impossible-to-simulate-particle-system-in-isaac-sim-during-rl-training/268610/3 "2023-10-24T20:04:46Z")

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Could you provide a small test case where I can repro the issue?

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<div class="post-metadata">

**Author:** ![pk21966](https://developer.download.nvidia.com/images/forums/profile-default-devtalk-84.png) [@pk21966](https://forums.developer.nvidia.com/u/pk21966)\
**Post date:** [December 27, 2023, 3:41pm UTC](https://forums.developer.nvidia.com/t/impossible-to-simulate-particle-system-in-isaac-sim-during-rl-training/268610/4 "2023-12-27T15:41:56Z")

</div>

Same problem, looking for the soln.

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<div class="post-metadata">

**Author:** ![1779789201](https://developer.download.nvidia.com/images/forums/profile-default-devtalk-84.png) [@1779789201](https://forums.developer.nvidia.com/u/1779789201)\
**Post date:** [January 4, 2024, 5:10pm UTC](https://forums.developer.nvidia.com/t/impossible-to-simulate-particle-system-in-isaac-sim-during-rl-training/268610/5 "2024-01-04T17:10:45Z")

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Have u ever simulate both particle and franka in isaac sim? i mean ‘sim’ without ‘gym’. When i set the backend and device in order to have a particle simulation. It seems like franka cant be simulated under this setting

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<div class="post-metadata">

**Author:** ![bechir.tabia](https://developer.download.nvidia.com/images/forums/profile-default-devtalk-84.png) [@bechir.tabia](https://forums.developer.nvidia.com/u/bechir.tabia)\
**Post date:** [January 26, 2025, 8:59pm UTC](https://forums.developer.nvidia.com/t/impossible-to-simulate-particle-system-in-isaac-sim-during-rl-training/268610/6 "2025-01-26T20:59:43Z")

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Hi, It seems that Articulation don’t work well with the torch backend. When using device to “cuda:0” with Numpy, it works fine (but you have to deactivate fabric), but when you change to torch backend, nothing works and articulations are screwed.