Using Flow in Standalone workflows in Issac Sim 4.5.0

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Isaac Sim Version

4.5.0

Operating System

Ubuntu 24.04.1 LTS

GPU Information

  • Model: GeForce RTX 3090
  • Driver Version: 535.183.01

I have been investigating use of flow in Issac sim (4.5.0) for both standalone and GUI workflows. When I run my flow scripts in the GUI everything works fine. When I run in Standalone the flow prims seem to have no attributes. I have created this short snippet for debugging.

from isaacsim import SimulationApp

simulation_app = SimulationApp({"headless": False})

from isaacsim.core.utils.extensions import enable_extension
from pxr import Gf
import omni.usd

extensions=["omni.flowusd.ui","omni.flowusd","omni.flowusd.bundle","omni.usd.schema.flow"]
for ext in extensions:
    enable_extension(ext)

stage = omni.usd.get_context().get_stage()

smoke_emitter_path = "/Smoke/SmokeEmitter"
if not stage.GetPrimAtPath(smoke_emitter_path):
    smoke_emitter = stage.DefinePrim(smoke_emitter_path, "FlowEmitterBox")
else:
    smoke_emitter = stage.GetPrimAtPath(smoke_emitter_path)
print(smoke_emitter.GetAttributes())
simulation_app.close()

In the GUI I get a list of attributes.
Standalone I just get

I haven’t managed to find any examples of flow use in the standalone workflow so it’s unclear whether I’m running into these issues because of a bug or there’s something extra I need to implement in standalone workfows.

Have you tried loading the entire USD file from the GUI into your standalone Python script? If so, does the issue still persist?

I’m facing the similar issue, i have flow prim in my environment and when i open the usd environment in isaac sim, the flow is simulation is visible, But when i launch isaac sim for robot training, at that time the flow simulation is not starting. I have all the required extensions enabled, but it still did not start the flow effect simulation.

Could you provide detailed steps and files for us to replicate your issue?