This is the professional bug report for your specific issue. I have formatted it to highlight the conflict between the SICK microScan3 Profile 5 and the ROS2 RTX Lidar Helper node in Isaac Sim 5.1.0.
[bug]SICK_microScan3_Profile_5_9.0m_25.0Hz.usd. (SICK microScan3) publishes empty ROS2 LaserScan topics despite correct Action Graph wiring
Describe the bug
When using the official SICK microScan3 Profile 5 USD asset with the ROS2 RTX Lidar Helper node, the ROS 2 topics are successfully created and visible in ros2 topic list, but they contain no data. ros2 topic echo remains blank even when the simulation is playing and all other articulation errors are cleared. The issue appears to be a failure in the OgnROS2PublishLaserScan node’s ability to calculate the 2D scan array from the new OmniSensorCore API used by the SICK sensors in version 5.1.0.
Steps to reproduce
* Load SICK_microScan3_Profile_5_9.0m_25.0Hz.usd into the stage.
* Create an Action Graph: On Playback Tick → Run One Simulation Frame → Create Render Product (1x1) → ROS2 RTX Lidar Helper.
* Set Lidar Prim to ROTARY scan type and Helper to laser_scan.
* Set azimuthRange to [-137.5, 137.5] (275° sweep).
* Enable Publish Full Scan.
* Run simulation and attempt to echo the topic:
ros2 topic echo /iw_hub_front_scan
Observation: Topic exists but no messages are published.
System Info
* Isaac Sim Version: 5.1.0
* OS: Ubuntu 22.04 (CARRUBUNTUWORKSTATION)
* GPU: NVIDIA RTX A4000 (8.41 ms frame time)
* CUDA: 12.x (Standard for 5.1.0)
* GPU Driver: 550+
Additional context
The SICK microScan3 prim in 5.1.0 uses the omnisensor:Core properties instead of the legacy RTX Lidar properties. Changing the scanType between SOLID_STATE and ROTARY does not resolve the issue for LaserScan messages. However, switching the Helper node to point_cloud output sometimes results in successful data transmission, suggesting the bug is specific to the 2D LaserScan serialization logic for this sensor model.
Checklist
* [x] I have checked that there is no similar issue in the repo (required)
* [x] I have checked that the issue is not in running Isaac Sim itself and is related to the repo
Acceptance Criteria
* [ ] ROS2 RTX Lidar Helper successfully publishes non-empty sensor_msgs/msg/LaserScan data for SICK microScan3 assets.
* [ ] The angle_increment and ranges array are correctly populated based on the omnisensor:Core azimuth settings.