ros-drivers/velodyne

Unable to project the lidar points/ray in rviz2

SyahirMuzni opened this issue · 4 comments

SyahirMuzni commented
  • OS and Version: [Ubuntu 20.04]
  • ROS Version: [Galactic]
  • Downloaded from Official Repository
  • Version: 2.2.0-1focal.20220430.170126

The bug
Unable to project lidar points/ray in rviz2. I was able to project it at one time but without 'tf', also there was no option 'velodyne' in the Fixed Frame. So I rewrite it and success to project it. But later, I can't even project the points at all.

To Reproduce
Steps to reproduce the behavior:

  1. source /opt/ros/galactic/setup.bash
  2. ros2 launch velodyne velodyne-all-nodes-VLP32C-launch.py
  3. On a new tab, rviz2
  4. Add, by topic pointcloud2
  5. Fixed frame, velodyne

Expected behavior
I expect it to project it as usual and I want to solve the 'tf' issues afterwards.

Additional notes
In the points drop down it's stated: "showing [0] points from [0] messages"

JWhitleyWork commented

@SyahirMuzni This is likely a frame issue. After you run the commands in your post, can you please run the following commands in a new terminal?

source /opt/ros/galactic/setup.bash
ros2 topic echo /velodyne_points | grep frame_id

The above command assumes that your points are being produced on /velodyne_points. If the frame_id that is put out is velodyne then there is something wrong with collecting the data. If it is not velodyne, then use whatever frame_id is shown in RViz.

cjffly commented

@JWhitleyWork I had the same issue as @SyahirMuzni described. After running

source /opt/ros/galactic/setup.bash
ros2 topic echo /velodyne_points | grep frame_id

it returned the velodyne as frame_id.

Is there a way to sniff what data is passing to the velodyne driver? Since the same data collecting pipeline works for ROS1 and can be shown in rviz1 but does not work for ROS2/rviz2

JWhitleyWork commented

@cjffly After finding the frame id as /velodyne, did you then set the Global Frame in rviz2 to /velodyne?

cjffly commented

@cjffly After finding the frame id as /velodyne, did you then set the Global Frame in rviz2 to /velodyne?

After I set the Global Frame to /velodyne, the points did show up. Thanks!

But the data shown is strange, not like what used to be in ros1. I will submit another issue related to this.