How to put on the home path in an XML file as an e

Question

I have a .world file in ROS for gazebo simulation which is an XML file.

How can I put on a dynamic home path instead of the static path in <uri> tag?

---

Here's my simplified .world file:

<?xml version="1.0" ?>
<sdf version='1.5'>
  <world name='default'>
    <visual name='base_link_visual_front_sonar'>
      <pose>0.109 0 0.209 0 -0 0</pose>
      <geometry>
      <mesh>
        <uri>/home/agn/catkin_ws/src/description/meshes/sonar.stl</uri> <!--Note-->
      </mesh>
      </geometry>
    </visual>
  </world>
</sdf>

---

How can I use $HOME instead of /home/agn?

I tried the following cases with the failed results:

<uri>~/catkin_ws/src/description/meshes/sonar.stl</uri>
<uri>$HOME/catkin_ws/src/description/meshes/sonar.stl</uri>
<uri>"$HOME/catkin_ws/src/description/meshes/sonar.stl"</uri>
<uri>${HOME}/catkin_ws/src/description/meshes/sonar.stl</uri>
<uri>"${HOME}/catkin_ws/src/description/meshes/sonar.stl"</uri>
<uri>"${sys:user.home}/catkin_ws/src/description/meshes/sonar.stl"</uri>
<uri>${sys:user.home}/catkin_ws/src/description/meshes/sonar.stl</uri>
<uri>${user.home}/catkin_ws/src/description/meshes/sonar.stl</uri>
<uri>"${user.home}/catkin_ws/src/description/meshes/sonar.stl"</uri>

Answer 1

According to the Gazebo tutorial Gazebo allows to find additional models at paths that are listed listed on the environment variable GAZEBO_MODEL_PATH.

Adding a path to an environment variable is well described in How to correctly add a path to PATH? and can be done like

PATH=$GAZEBO_MODEL_PATH:/your/path/to/check

Now you are able to set the uri like

<uri>model://relative/path/file.stl</uri>

Note that there is also a hacks which allows changing the environment variable in the package.xml.