@nkoenig : In my world model, I have all the models in the .world file and don't have separate models directory. I used the GUI to create my world so the codes were edited in the same .world file. Now if I want to write plugins for .world file, will it be possible ? Also I want to make the robot move from one point to other. Can I do that just by using Gazebo or Do I need to take help from ROS ? I can post the code of my ".world" file if you want. Thanks in advance.