Cant fetch /gazebo_models from server.

edit

Hello people,

I want to run the project Ros-NetSim (https://github.com/alelab-upenn/ros-n...) and as a starting point they have build an example package, that works fine for me, so the building process of the project must have finished without problems. Now they also have an custom_main_empty_world.launch file in https://github.com/alelab-upenn/ros-n... the project, that starts gazebo and ROS nodes, which models the communication channel between models in the gazebo world(as I understood it). The probem is, that the following error occurs when doing

roslaunch physics_coordinator custom_main_empty_world.launch

the error [FATAL] [1649960433.979917624]: [gazebo_custom_main] failed to fetch required param "/gazebo_models" from server is created. This error comes from the physics_coordinator package that gets build from the gazebo_custom_main.cpp from line 236:

 XmlRpc::XmlRpcValue gazebo_models_list;
  if (!nh.getParam("/gazebo_models", gazebo_models_list)) {
    GCM_FATAL("failed to fetch required param \"/gazebo_models\" from server");
    exit(EXIT_FAILURE);
  }
  ROS_ASSERT(gazebo_models_list.getType() == XmlRpc::XmlRpcValue::TypeArray);

Nowhere in this cpp file I could find the parameter /gazebo_models to be set for the node handel, so i assume it done in some function. I am using ROS melodic as suggested and I switched GAZEBO_MODEL_DATABASE_URIto https://github.com/osrf/gazebo_models in the ros setup, but it didnt change anything . Can anyone tell me how this error might be created? Is there some setting missing? Some node not launched?

Here is a roslaunch log

[roslaunch][INFO] 2022-04-14 20:20:32,567: Checking log directory for disk usage. This may take a while.
Press Ctrl-C to interrupt
[roslaunch][INFO] 2022-04-14 20:20:32,569: Done checking log file disk usage. Usage is <1GB.
[roslaunch][INFO] 2022-04-14 20:20:32,569: roslaunch starting with args ['/opt/ros/melodic/bin/roslaunch', 'physics_coordinator', 'custom_main_empty_world.launch']
[roslaunch][INFO] 2022-04-14 20:20:32,569: roslaunch env is {'LC_NUMERIC': 'de_DE.UTF-8', 'ROS_DISTRO': 'melodic', 'ROS_LOG_FILENAME': '/home/q1/Desktop/roslog/9242ba06-bc1f-11ec-92e8-0800274edeb4/roslaunch-1-1909.log', 'QT4_IM_MODULE': 'xim', 'PKG_CONFIG_PATH': '/home/q1/ros-net-sim/devel/lib/pkgconfig:/opt/ros/melodic/lib/pkgconfig', 'WINDOWPATH': '1', 'XDG_CURRENT_DESKTOP': 'ubuntu:GNOME', 'ROS_LOG_DIR': '/home/q1/Desktop/roslog', 'LC_PAPER': 'de_DE.UTF-8', 'ROSLISP_PACKAGE_DIRECTORIES': '/home/q1/ros-net-sim/devel/share/common-lisp', 'QT_IM_MODULE': 'ibus', 'LOGNAME': 'q1', 'USER': 'q1', 'PATH': '/opt/ros/melodic/bin:/home/q1/.local/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games:/snap/bin', 'XDG_VTNR': '1', 'HOME': '/home/q1', 'CMAKE_PREFIX_PATH': '/home/q1/ros-net-sim/devel:/opt/ros/melodic', 'DISPLAY': ':0', 'SSH_AGENT_PID': '10835', 'LANG': 'en_US.UTF-8', 'TERM': 'xterm-256color', 'SHELL': '/bin/bash', 'GAZEBO_RESOURCE_PATH': '/usr/share/gazebo-9', 'XAUTHORITY': '/run/user/1000/gdm/Xauthority', 'SESSION_MANAGER': 'local/1:@/tmp/.ICE-unix/10700,unix/1:/tmp/.ICE-unix/10700', 'LC_MEASUREMENT': 'de_DE.UTF-8', 'QT_ACCESSIBILITY': '1', 'LD_LIBRARY_PATH': '/home/q1/ros-net-sim/devel/lib:/opt/ros/melodic/lib', 'GNOME_DESKTOP_SESSION_ID': 'this-is-deprecated', 'CLUTTER_IM_MODULE': 'xim', 'TEXTDOMAIN': 'im-config', '_': '/opt/ros/melodic/bin/roslaunch', 'XMODIFIERS': '@im=ibus', 'ROS_MASTER_URI': 'http://localhost:11311', 'XDG_RUNTIME_DIR': '/run/user/1000', 'GPG_AGENT_INFO': '/run/user/1000/gnupg/S.gpg-agent:0:1', 'ROS_PYTHON_VERSION': '2', 'USERNAME': 'q1', 'XDG_SESSION_DESKTOP': 'ubuntu', 'SHLVL': '1', 'ROS_VERSION': '1', 'GTK_IM_MODULE': 'ibus', 'LC_ADDRESS': 'de_DE.UTF-8', 'PYTHONPATH': '/home/q1/ros-net-sim/devel/lib/python3/dist-packages:/opt/ros/melodic/lib/python2.7/dist-packages', 'SSH_AUTH_SOCK': '/run ...