What is the need to set the environmental variable HUSKY_GAZEBO_DESCRIPTION?
I was going through the husky_gazebo wiki page.
The second step is this -
$ export HUSKY_GAZEBO_DESCRIPTION=$(rospack find husky_gazebo)/urdf/description.gazebo.xacro
Simply, launching the husky_gazebo simulation using roslaunch works fine -
$ roslaunch husky_gazebo husky_empty_world.launch
Why do we need the second step? Also, do we need to run that step every time before launching the husky_gazebo using roslaunch (third step)?