isaac-sim Isaac Sim ROS 2 Bridge
Architecture
The ROS 2 Bridge in Isaac Sim 6.0 is extension-based (isaacsim.ros2.bridge) and built on OmniGraph action graphs. Publishers, subscribers, and services are only active when play is pressed.
Extension Stack
| Extension | Purpose |
|---|---|
isaacsim.ros2.core |
Backend libraries, settings, lightweight ROS 2 libs |
isaacsim.ros2.nodes |
OmniGraph nodes for topics/services |
isaacsim.ros2.bridge |
Top-level bridge extension (enables all) |
isaacsim.ros2.tf_viewer |
TF tree visualization |
isaacsim.ros2.urdf |
URDF import with ROS 2 conventions |
isaacsim.ros2.examples |
Sample scenes (Nova Carter, iw_hub, hospital, office) |
isaacsim.ros2.sim_control |
Simulation control via ROS 2 services |
Prerequisites
No manual setup is required for the default workflow. When isaacsim.ros2.core starts, it reads ROS_DISTRO; if unset, it falls back to the lightweight ROS 2 libs bundled inside the extension and sets internal_lib_fallback=True. The isaac-sim.sh / python.sh launchers auto-source setup_ros_env.sh, which exports ROS_DISTRO, RMW_IMPLEMENTATION, and LD_LIBRARY_PATH for the bundled libs before the process starts.
Source a system ROS 2 install (/opt/ros/<distro>/setup.bash) in the parent shell only when you need message types or RMW implementations not provided by the bundled libs. On Linux, LD_LIBRARY_PATH must be set in the parent shell (the dynamic linker reads it at process start), which is why this step is shell-sourced and not handled by the extension at runtime.
Pass --no-ros-env to bypass the auto-sourcing; in that case the parent shell must provide a working ROS 2 environment.
[Code: scripts/prerequisites.sh]
OmniGraph ROS 2 Nodes
All ROS 2 communication is configured through OmniGraph action graphs. Key node types:
Publishers
| Node Type | Topic Type | Use Case |
|---|---|---|
ROS2PublishClock |
rosgraph_msgs/Clock |
Sim time sync |
ROS2PublishJointState |
sensor_msgs/JointState |
Joint positions/velocities |
ROS2PublishOdometry |
nav_msgs/Odometry |
Robot odometry |
ROS2PublishLaserScan |
sensor_msgs/LaserScan |
Lidar data |
ROS2PublishImage |
sensor_msgs/Image |
Camera RGB/depth |
ROS2PublishCameraInfo |
sensor_msgs/CameraInfo |
Camera intrinsics |
ROS2PublishTransformTree |
tf2_msgs/TFMessage |
TF frames |
ROS2PublishSemanticLabels |
std_msgs/String |
Semantic segmentation labels |
ROS2PublishPointCloud |
sensor_msgs/PointCloud2 |
Lidar/depth point clouds |
ROS2PublishImu |
sensor_msgs/Imu |
IMU data |
Subscribers
| Node Type | Topic Type | Use Case |
|---|---|---|
ROS2SubscribeJointState |
sensor_msgs/JointState |
Joint commands |
ROS2SubscribeTwist |
geometry_msgs/Twist |
Velocity commands (cmd_vel) |
ROS2SubscribeAckermannDrive |
ackermann_msgs/AckermannDriveStamped |
Ackermann steering commands |
Generic / extra
| Node Type | Use case |
|---|---|
ROS2Publisher / ROS2Subscriber |
generic publish/subscribe for arbitrary message types |
ROS2PublishBoundingBox2D / ROS2PublishBoundingBox3D |
annotator output to ROS 2 |
ROS2PublishRgbd |
combined RGB+D publishing |
ROS2PublishSemanticSegmentation / ROS2PublishInstanceSegmentation |
segmentation outputs |
Setting Up a ROS 2 Bridge Graph (Python)
The repo ships a canonical reference for building a ROS 2 publishing action graph with og.Controller.edit(...), including connecting OnPlaybackTick to publisher nodes, wiring IsaacReadSimulationTime into a ROS2PublishClock, and creating a matching rclpy subscriber inside the same script.
- Reference example:
source/standalone_examples/api/isaacsim.ros2.bridge/clock.py
When extending this pattern, use the current isaacsim.ros2.bridge.ROS2Publish* / ROS2Subscribe* node names (the legacy omni.isaac.ros2_bridge.* namespace is deprecated and will not load on Kit 110).
Migration: see Migrating ROS 2 OmniGraph nodes for the node-by-node rename map, and Renaming Extensions for the broader
omni.isaac.*→isaacsim.*mapping.
Multi-Robot Namespacing
For multi-robot scenes, each robot needs its own namespace for ROS 2 topics. The repo's multi-robot scenario (Carter on hospital/office) demonstrates the manual loading + per-robot setup pattern; scripts/multi_robot_namespacing.py in this skill provides the per-robot graph factory with namespaced odom / TF / cmd_vel.
- Scenario reference:
source/standalone_examples/api/isaacsim.ros2.bridge/carter_multiple_robot_navigation.py - Per-robot graph factory:
scripts/multi_robot_namespacing.py
Nav2 Integration
To use Nav2 with Isaac Sim ROS 2 Bridge:
- Publish required topics:
/odom,/tf,/scan(or/pointcloud),/joint_states - Subscribe to:
/cmd_vel - Publish sim clock on
/clockand setuse_sim_time: truein Nav2 params
Known Issues (Isaac Sim 6.0 rc.22)
- ROS 2 bridge only activates on
timeline.play()— topics are not published in stopped state - Camera publishers require camera prims to have render products attached
- TF tree can become inconsistent if robot prim paths change at runtime
- Bundled ROS 2 libs may lack message types needed for custom topics — source a system ROS 2 install in the parent shell before launching Isaac Sim
Sample Scenes
Pre-built example USD files (from isaacsim.ros2.examples):
| Scene | Path | Description |
|---|---|---|
| Nova Carter Navigation | /Isaac/Samples/ROS2/Scenario/carter_warehouse_navigation.usd |
Single robot Nav2 |
| Nova Carter Joint States | /Isaac/Samples/ROS2/Scenario/carter_warehouse_navigation_joint_states.usd |
With joint state publishing |
| iw_hub Navigation | /Isaac/Samples/ROS2/Scenario/iw_hub_warehouse_navigation.usd |
iw_hub AMR |
| Multi-Robot Navigation | ROS2/Navigation/Multiple Robots category | Fleet Nav2 |
| Hospital Scene | /Isaac/Samples/ROS2/Scenario/hospital_scene.usd |
Perceptor + hospital |
| Office Scene | /Isaac/Samples/ROS2/Scenario/office_scene.usd |
Office navigation |