Publishing rate of RTX lidar

I want to use the RTX lidar, rather than the current PhysX one. It has two features we really need: the ability to have non-uniform channel distributions and the ability to bounce off of dynamic objects. Our real lidar completes one full revolution every 10Hz. To simulate our real setup, what I really want is for Isaac to publish the lidar point clouds to a ROS2 topic at 10Hz. Every message would be one 360 degree scan.

I am trying to figure out how to achieve this.

I ran the RTX lidar publishing to ROS2 example. I did some experiments, only changing the physics_dt and rendering_dt of the simulation. I learned a few things.

  • The amount of points in the scan directly relates to the rendering_dt. Using rendering_dt of less than 10Hz results in each message having an incomplete scan, a circular section of the full scan (pie-slice-shaped).
  • The publishing frequency (measured by ros2 topic hz /point_cloud) is pretty inscrutable. Even running rviz can decrease this rate (despite my fast workstation). Maybe it is due to the number of subscribers?

Questions

  1. How do I get the RTX lidar to consistently output one full scan at 10 Hz?
  2. Can you explain the relation between rendering frequency, lidar configuration, and publishing rate?

I’ve attached my experiments on the publishing rate w.r.t. physics / rendering frequency for completeness.

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Hi @jrb2 ,
Any progress on this issue?