<?xml version="1.0" ?>

<sdf version="1.5">

<world name="default">

<include>

<uri>model://sun</uri>

</include>

<include>

<uri>model://ground_plane</uri>

</include>

<include>

<uri>model://pr2</uri>

<name>pr2_mud</name>

<pose>0.0 0 0 0 0 0</pose>

</include>

<model name="mud_pit">

<pose>0 0.0 0.5 0 0 0</pose>

<static>true</static>

<link name="link">

<collision name="collision">

<geometry>

<box>

<size>5 1 1</size>

</box>

</geometry>

<surface>

<contact>

<collide_without_contact>true</collide_without_contact>

<collide_without_contact_bitmask>2</collide_without_contact_bitmask>

</contact>

</surface>

</collision>

<visual name="visual">

<geometry>

<box>

<size>5 1 1</size>

</box>

</geometry>

<material>

<ambient>0.2 0.2 0.2 1.0</ambient>

<diffuse>.421 0.225 0.0 1.0</diffuse>

</material>

</visual>

<sensor name="mud_contact" type="contact">

<always_on>true</always_on>

<update_rate>1000</update_rate>

<contact>

<collision>collision</collision>

</contact>

</sensor>

</link>

<plugin name="gazebo_mud" filename="libMudPlugin.so">

<contact_sensor_name>link/mud_contact</contact_sensor_name>

<stiffness>0.0</stiffness>

<damping>1.0</damping>

<link_name>pr2_mud::r_gripper_l_finger_link</link_name>

</plugin>

</model>

</world>

</sdf>