As you can see below screenshot. The particles penetrate the conveyor belt, also belt speed does not move the particles at all. Testing with a just normal cube with Rigid Body with Collider Preset works normally, but when I change them into the particles.
The fluid checkbox is deactivated and also tried couple of different physics settings but still not working.
Hi @hosei2, thank you for posting your issue. I think spawning normal prims seems to make sense in this application. What is the goal of using Particle Systems?
Thank you for the reply. The goal is to simulate mining applications, where sand or pebble stones are transported using the conveyor belt.
My first approach was to use Particle Systems to simulate these materials on the conveyor belt. Do you have any better approach you could recommend for this application?
One recommended method is to spawn Rigid Bodies with collider preset as you were doing originally. If you know ahead of time how many spheres you want spawn and you want them all at once, then Point Instancer is a good solution.
Here is an example script to spawn Rigid Bodies dynamically:
# Copyright (c) 2022-2024, NVIDIA CORPORATION. All rights reserved.
#
# NVIDIA CORPORATION and its licensors retain all intellectual property
# and proprietary rights in and to this software, related documentation
# and any modifications thereto. Any use, reproduction, disclosure or
# distribution of this software and related documentation without an express
# license agreement from NVIDIA CORPORATION is strictly prohibited.
#
from isaacsim import SimulationApp
# Create simulation app (not headless so we can see the particles)
simulation_app = SimulationApp({"headless": False})
from isaacsim.core.api import World
from isaacsim.core.api.objects import DynamicSphere
import numpy as np
import random
import time
# Create world with CPU backend
my_world = World(stage_units_in_meters=1.0)
print("Using CPU backend")
# Add default ground plane
my_world.scene.add_default_ground_plane()
# Define spawn region
spawn_region = {
"x_min": -1.0, "x_max": 1.0,
"y_min": -1.0, "y_max": 1.0,
"z_min": 0.5, "z_max": 2.0
}
# Particle parameters
particle_radius = 0.05
spawn_interval = 2.0 # Time between spawning new particles
particles_per_spawn = 20
# List to keep track of all spawned particles
particles = []
# Reset world to initialize scene
my_world.reset()
# Main simulation loop
start_time = time.time()
last_spawn_time = start_time
print("Simulation started. New particles will be spawned every 2 seconds.")
print("Press Ctrl+C to exit.")
while simulation_app.is_running():
current_time = time.time()
elapsed_time = current_time - start_time
# Spawn new particles every spawn_interval seconds
if current_time - last_spawn_time >= spawn_interval:
for _ in range(particles_per_spawn):
# Generate random position
x = random.uniform(spawn_region["x_min"], spawn_region["x_max"])
y = random.uniform(spawn_region["y_min"], spawn_region["y_max"])
z = spawn_region["z_max"] # Spawn at the top of the region
# Generate random color
color = np.array([random.random(), random.random(), random.random()])
# Create a unique name for the particle
particle_name = f"particle_{len(particles)}"
# Create the dynamic sphere
particle = my_world.scene.add(
DynamicSphere(
name=particle_name,
position=np.array([x, y, z]),
prim_path=f"/World/{particle_name}",
radius=particle_radius,
color=color,
mass=1.0
)
)
# Add to our list of particles
particles.append(particle)
print(f"Time: {elapsed_time:.1f}s - Spawned {particles_per_spawn} new particles. Total: {len(particles)}")
last_spawn_time = current_time
my_world.step(render=True)
# Cleanup
simulation_app.close()
We noticed that this topic hasn’t received any recent responses, so we are closing it for now to help keep the forum organized.
If you’re still experiencing this issue or have additional questions, please feel free to create a new topic with updated details. When doing so, we recommend mentioning or linking to this original topic in your new post—this helps provide context and makes it easier for others to assist you.
Thank you for being part of the NVIDIA Isaac Sim community.
