assets/steering_marker.urdf

<?xml version="1.0"?>
<robot name="object">
  <link name="object">
    <visual>
      <origin xyz="0 0 0"/>
      <geometry>
        <box size="0.5 0.05 0.05"/>
      </geometry>
      <material name="mat">
        <color rgba="0.5 0.5 0.5 1"/>
      </material>
    </visual>
  </link>
</robot>