Gazebo world file:

• We can create models for the Gazebo physics simulator.
  • • Simulation description format (.sdf) models.
    • Multiple .sdf models composed in a world file.
    • More features than URDF (friction, non-robotic elements).
    • Spawn URDF models with spawner ROS node.
• Functionality can be configured:
  • • With a logical camera plugin.

The models reside in:

• hrwros_gazebo ROS package
  • • hrwros_gazebo/models
• Camera model files
  • • • hrwros_gazebo/models/logical_camera/model.sdf 
  • Conveyor object(s)
    • • config/conveyor_objects.yaml
      • simple box object

We can include .sdf models to our world with the include tag. You will have to add two logical camera models:

 <include> 
   <uri>model://conveyor</uri>
     <pose>1.2 5 0 0 0 -1571</pose>
   </include
   < -- include logical camera model(s) here -- >
  </world>
</sdf>