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Isaac Sim Configuration#

Configuration files controlling Isaac Sim simulation behavior.

Configuration Files#

Located in /isaac-sim/sil/configs/:

  • default_config_ros.yaml - Main simulation parameters

  • cameras.yaml - Camera registration for VST

  • default_command.txt - Digital human behavior

default_config_ros.yaml#

Main simulation configuration:

isaacsim.replicator.agent:
  version: 0.7.0

  character:
    asset_path: omniverse://content.ov.nvidia.com/Projects/Teams/Metropolis/Characters/DH_Characters_Extended/
    num: 3
    command_file: /isaac-sim/sil/configs/default_command.txt

  global:
    seed: 123456789
    simulation_length: 3000

  replicator:
    writer: RTSPWriter
    parameters:
      rtsp_stream_url: rtsp://localhost:8553/RTSPWriter
      rtsp_rgb: true

  scene:
    asset_path: /isaac-sim/sil/scenes/indicator_warehouse_20x20_layout_overflow_test.usd

  sensor:
    camera_num: 3

Key Parameters#

Parameter

Default

Description

character.num

3

Number of digital humans (IRA agents)

character.asset_path

Omniverse URL

Digital human models location (requires OMNI_PASS)

global.seed

123456789

Random seed for reproducible scenarios

global.simulation_length

3000

Total frames (3000 / 30 FPS = 100 seconds)

replicator.writer

RTSPWriter

Output format for camera feeds

rtsp_stream_url

localhost:8553

MediaMTX RTSP server address

scene.asset_path

USD file path

Warehouse scene to load

sensor.camera_num

3

Number of cameras to create

cameras.yaml#

Camera registration configuration for VST:

cameras:
  - name: Camera
    rtsp_path: RTSPWriter_World_Cameras_Camera_rgb

  - name: Camera_01
    rtsp_path: RTSPWriter_World_Cameras_Camera_01_rgb

  - name: Camera_02
    rtsp_path: RTSPWriter_World_Cameras_Camera_02_rgb

rtsp:
  host: ${HOST_IP}
  port: 8553

Camera registration:

  • name: Camera identifier in VST

  • rtsp_path: RTSP stream suffix

  • Full URL: rtsp://${HOST_IP}:8553/${rtsp_path}

When Isaac Sim starts with --enable-vst, cameras automatically register with VST using these definitions.

Playback Segments#

Forklift movement defined in /isaac-sim/sil/playback/segments.json:

{
  "segments": [
    {"duration": 16.0, "linear_x": 1.0, "angular_z": 0.0, "note": "Forward"},
    {"duration": 5.0, "linear_x": 0.0, "angular_z": 0.0, "note": "Idle"},
    {"duration": 16.0, "linear_x": -1.0, "angular_z": 0.0, "note": "Backward"},
    {"duration": 5.0, "linear_x": 0.0, "angular_z": 0.0, "note": "Idle"}
  ]
}

Segment parameters:

  • duration: Seconds to execute this segment

  • linear_x: Forward (+) / backward (-) velocity in m/s

  • angular_z: Turning rate in rad/s (0 = straight)

  • note: Description (not used by code)

Loaded by playback script node in Action Graph. Segments execute sequentially, loop if LOOP=True in script.

Common Adjustments#

Change Simulation Length#

global:
  simulation_length: 9000  # 5 minutes at 30 FPS

Test Without Humans#

character:
  num: 0  # Forklift-only scenario

Modify Forklift Path#

Edit segments.json:

{
  "segments": [
    {"duration": 10.0, "linear_x": 1.5, "angular_z": 0.0, "note": "Fast entry"},
    {"duration": 3.0, "linear_x": 0.0, "angular_z": 0.0, "note": "Stop"}
  ]
}

Execution Script#

Isaac Sim scenarios are executed using run_sdg.sh.

Command Line Parameters#

Parameter

Description

-c, --config_file

Path to IRA config file (required)

--start

Automatically start data generation (no manual UI start needed)

--headless

Run without GUI window (for automated testing)

--enable-vst

Enable VST sensor registration for camera streams

--cameras-config

Path to cameras.yaml for VST integration

Example execution:

docker exec -d isaac-sim bash -lc 'cd /isaac-sim/sil/scripts && \
  ./run_sdg.sh -c /isaac-sim/sil/configs/default_config_ros.yaml \
  --start --headless --enable-vst \
  --cameras-config /isaac-sim/sil/configs/cameras.yaml'

VST Integration:

  • --enable-vst registers cameras with VST automatically

  • Reads camera definitions from cameras.yaml

  • Constructs RTSP URLs: rtsp://${HOST_IP}:8553/${rtsp_path}

  • Requires HOST_IP and VST_BASE_URL environment variables

Example with UI:

Allow X11 connections:

xhost +local:

Stop all SIL docker compose containers, then run cleanup and setup:

cd deployments
../closed-loop-testing/scripts/cleanup_all_datalog.sh sil
../closed-loop-testing/scripts/setup.sh sil

Start SIL docker compose:

docker compose --env-file profiles/sil.env up -d --build

Then start Isaac Sim with UI:

docker exec -it isaac-sim bash -lc 'cd /isaac-sim/sil/scripts && \
  ./run_sdg.sh -c /isaac-sim/sil/configs/default_config_ros.yaml \
  --start --enable-vst \
  --cameras-config /isaac-sim/sil/configs/cameras.yaml'
Isaac Sim UI

Tip

You can inject commands into a running simulation to control IRA agents in real time — see the official documentation: Actor Control with Replicator Agent.

Next Steps#