ROS Unity unable to connect with no connection information

I am trying to run the unity-ros-integration tutorials following every step. Was able to build the catkin project, set environment, and get the robo_demo.launch file to run. However, Ping from both devices, which are connected to same wifi, and the pings were successful. But if I run the pos publisher rostopic echo pos_rot from windows unity and then a subscriber from Linux ROS, the terminal hangs with the following message:

WARNING: topic [/pos_rot] does not appear to be published yet

ROS Master is running, and no message about connection is available when I start or stop Unity editor play.

setting /run_id to 5c1a867c-f87d-11eb-b01b-336712ef486f
process[rosout-1]: started with pid [174801]
started core service [/rosout]
process[position_service_and_endpoint/position_service-2]: started with pid [174808]
process[position_service_and_endpoint/server_endpoint-3]: started with pid [174809]

Just each time when I stop Unity editor play, on Linux ROS master output the following exception:

[ERROR] [1628450321.770259]: Exception: No more data available
[ERROR] [1628450346.369471]: Exception: No more data available
[ERROR] [1628450567.044703]: Exception: No more data available

No errors given from the player log,

It seems that there is some connection between ROS and Unity judging from the screenshot. As you can see from the blue error on the upper left corner:

Environment (please complete the following information, where applicable):

• Unity Version: [e.g. Unity 2020.3.13f1]
• Unity machine OS + version: [Windows 10]
• ROS machine OS + version: [Ubuntu 20.04LTS, ROS Noetic]
• ROS–Unity communication: [Wifi]
• Branch or version: [master]

Please, can anyone help.

[at669]

Glad to hear the other demos worked! After further investigation, you’re absolutely correct, the robo_demo.launch file is outdated. The paths in the launchfile point to the wrong locations–I’ve created an internal ticket for investigation.

Until the tutorial is fully updated, as a workaround, you should be able to replace your launch file with something like this:

<launch>
    <param name="ROS_IP" value="192.168.44.73" />
    <node name="position_service" pkg="unity_robotics_demo" type="position_service.py" args="--wait" output="screen" respawn="true" />
    <node name="server_endpoint" pkg="ros_tcp_endpoint" type="default_server_endpoint.py" args="--wait" output="screen" respawn="true" />
</launch>

Ticket#: AIRO-1118

[at669]

Hi @keli95566, the fix has been merged to the dev branch and will eventually make its way to main in the next release. Feel free to try out the changes on your end! I’ll close this issue for now, but go ahead and reopen it if the problem persists, or open a new issue if a new problem crops up. Thanks for your contribution!