What are frames? Where are they?
I'm using Ros Melodic, Gazebo 9.7.0 in an Ubuntu 18.04.
I don't understand frames. Where I can find more information about frames? Especially for world frame.
If I'm using ROS and Gazebo, where is the world frame? Thanks.
Not sure this is a ROS question (seeing the explicit mention of Gazebo), but: can you please check whether #q270403 clears this up?
Might also make sense to have a look at REP 103 (coordinate frame conventions) and REP 105 (coordinate frames for mobile platforms) where there is also an explanation of commonly used frames.