RTXLiDar implementation issue

Omniverse Isaac Sim
1

When creating an instance of the RTX Lidar The following error is produced. I have multiple instances of lidars running to be read by ROS2. Has anyone experienced this issue?

[Warning] [omni.isaac.sensor.plugin] IsaacComputeRTXLidarFlatScan: lowest elevation emitter is 0.320000, not 0.

class RosRTXLidar():
    def __init__(
        self,
        parent_prim_path: str
    ) -> None:

        self._initialized = True

        # Locate Isaac Sim assets folder to load environment and robot stages
        self._assets_root_path = nucleus.get_assets_root_path()
        if self._assets_root_path is None:
            carb.log_error("Could not find Isaac Sim assets folder")
            self._initialized = False
            

        # Create the lidar sensor that generates data into "RtxSensorCpu"
        # Sensor needs to be rotated 90 degrees about X so that its Z up

        # Possible options are Example_Rotary and Example_Solid_State
        # drive sim applies 0.5,-0.5,-0.5,w(-0.5), we have to apply the reverse
        _, self._sensor = omni.kit.commands.execute(
            "IsaacSensorCreateRtxLidar",
            path="/sensor",
            parent=parent_prim_path,
            config="Example_Rotary",
            translation=(0, 0, 0),
            orientation=Gf.Quatd(1.0, 0.0, 0.0, 0.0),  # Gf.Quatd is w,i,j,k
        )

        # RTX sensors are cameras and must be assigned to their own render product
        self._hydra_texture = rep.create.render_product(self._sensor.GetPath(), [1, 1], name=parent_prim_path.replace("/","_"))

        self._simulation_context = SimulationContext(physics_dt=1.0 / 60.0, rendering_dt=1.0 / 60.0, stage_units_in_meters=1.0)

        # Create Point cloud publisher pipeline in the post process graph
        self._writer = rep.writers.get("RtxLidar" + "ROS2PublishPointCloud")
        self._writer.initialize(topicName=parent_prim_path + "/point_cloud", frameId= parent_prim_path)
        self._writer.attach([self._hydra_texture])

        # Create the debug draw pipeline in the post process graph
        self._writer = rep.writers.get("RtxLidar" + "DebugDrawPointCloud")
        self._writer.attach([self._hydra_texture])


        # Create LaserScan publisher pipeline in the post process graph
        self._writer = rep.writers.get("RtxLidar" + "ROS2PublishLaserScan")
        self._writer.initialize(topicName=parent_prim_path + "/laser_scan", frameId=parent_prim_path)
        self._writer.attach([self._hydra_texture])



    def run_lidar(self):
        self._simulation_context.play()

    def stop_lidar(self):
        self._simulation_context.stop()
3

The flat scan node is made to be used on lidar that have 0 elevation angle. You can use it on ones that have non-zero, but since there is no elevation in the scan message, it will be ignored.

You are seeing a warning that the profile you are using, “Example_Rotary” is not a 0 elevation lidar. It is not an error, just a warning. You can ignore it now that you understand it.

4

Alright that makes sense does it say that some where in the documentation?

5

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