After designing the xacro file, we can use the following command to convert it into a UDRF file:

    $ rosrun xacro xacro.py pan_tilt.xacro > pan_tilt_generated.urdf
  

We can use the following line in the ROS launch file for converting xacro to UDRF and use it as a robot_description parameter:

  <param name="robot_description" command="$(find xacro)/xacro.py 
 $(find mastering_ros_robot_description_pkg)/urdf/pan_tilt.xacro" 
 />

We can view the xacro of pan and tilt by making a launch file, and it can be launched using the following command:

    $ roslaunch mastering_ros_robot_description_pkg view_pan_tilt_xacro.launch