fix: Car Junction universe loading for Gazebo Harmonic

[Aaravanand00]

Summary

Fixed the Car Junction exercise universe not loading in Gazebo Harmonic.

Changes Made

Launch file (Launchers/car_junction.launch.py)

• Set GZ_SIM_RESOURCE_PATH with correct model directories:
  • custom_robots/models
  • /opt/jderobot/CustomRobots/car_junction/models
  • /opt/jderobot/Worlds
• Added Gazebo GUI client launch (was missing, only server was launching)
• Fixed gz_args format from list to string
• Removed duplicate imports

World file (Worlds/road_junction.world)

• Fixed cloud mesh path from model://sky/meshes/CloudMedium2.obj to model://hatchback/meshes/CloudMedium2.obj

Root Cause

The universe was not loading because:

1. GZ_SIM_RESOURCE_PATH was not set, so Gazebo couldn't find local models like waymo_light and hatchback
2. Cloud mesh was referencing non-existent model://sky/ directory

Files Changed

• Launchers/car_junction.launch.py
• Worlds/road_junction.world

Fixes #3231

[Aaravanand00]

Hi @javizqh sir,

I've created a new PR in the RoboticsInfrastructure repository with the fix for Gazebo Harmonic:

Changes made:

• Added GUI client launch for Gazebo Harmonic
• Updated GAZEBO_MODEL_PATH to GZ_SIM_RESOURCE_PATH
• Fixed bridge message types for Harmonic compatibility
• Fixed gz_args syntax

Please review when you get a chance. Thanks!

[javizqh]

Please upload a video of the universe loading in Robotics Academy

[Aaravanand00]

Hi @javizqh sir,

Successfully tested PR #630 with Gazebo Harmonic. Attaching video proof:

Video 1: Gazebo Harmonic loading Car Junction world
link : https://drive.google.com/file/d/1lrFd1g073DmAzkOWjGBL9U3Qb9Wb2p-O/view?usp=sharing

Video 2: Exercise running via web interface (status: "application_running")
link : https://drive.google.com/file/d/1UJ5NofafBxqW3KcDqkM1NoipQI7rPdd7/view?usp=sharing

Confirmed working: ✅ Gazebo Harmonic launches without errors
✅ World and models load correctly
✅ Web interface connects successfully
✅ Application executes and runs stably

Tested on Docker with jderobot/robotics-academy:latest. The migration to Gazebo Harmonic is successful
and sir sorry for late response I'm in travelling from 4-5 days that's why I record now and sir I'm try many times but Gazebo GUI window VNC/X11 will not properly render but simulation was running in the background and video you'll see that world was loaded and application was running means code was executed .

[javizqh]

Please, try to fix your issues with vnc, probably caused by not launching robotics academy with the default instructions (we do not use localhost neither port 8001). As right now the status is the same as it was before, because the universe already loaded outside the RADI and the application status was "application_running"