diff --git a/Migration.md b/Migration.md
index 701ae444c4..ab87e91c01 100644
--- a/Migration.md
+++ b/Migration.md
@@ -5,6 +5,13 @@ Deprecated code produces compile-time warnings. These warning serve as
 notification to users that their code should be upgraded. The next major
 release will remove the deprecated code.
 
+## Ignition Gazebo 4.0.0 to 4.X.X
+
+* Ignition Gazebo 4.0.0 enabled double sided material by default but this
+caused shadow artifacts to appear on some meshes. Double sided material is
+now disabled and made an opt-in feature. Users can configure this property
+in SDF by setting the `<visual><material><double_sided>` SDF element.
+
 ## Ignition Gazebo 3.x to 4.x
 
 * The `RenderUtil::SetEnabledSensors` callback in gazebo rendering has a new
diff --git a/examples/worlds/tunnel.sdf b/examples/worlds/tunnel.sdf
index 484c80ea67..796d77fd7b 100644
--- a/examples/worlds/tunnel.sdf
+++ b/examples/worlds/tunnel.sdf
@@ -1,6 +1,11 @@
 <?xml version="1.0" ?>
 <!--
   World containing a long tunnel and a vehicle.
+
+  Run with `--levels` for the tunnels to load and unload as the vehicle moves.
+
+  Use the WASDX keys to drive the vehicle.
+
 -->
 <sdf version="1.6">
   <world name="diff_drive">
@@ -16,10 +21,149 @@
       <origin_visual>false</origin_visual>
     </scene>
 
+    <gui fullscreen="0">
+
+      <!-- 3D scene -->
+      <plugin filename="GzScene3D" name="3D View">
+        <ignition-gui>
+          <title>3D View</title>
+          <property type="bool" key="showTitleBar">false</property>
+          <property type="string" key="state">docked</property>
+        </ignition-gui>
+
+        <engine>ogre2</engine>
+        <scene>scene</scene>
+        <ambient_light>0.4 0.4 0.4</ambient_light>
+        <background_color>0.8 0.8 0.8</background_color>
+        <camera_pose>-6 0 6 0 0.5 0</camera_pose>
+      </plugin>
+
+      <!-- World control -->
+      <plugin filename="WorldControl" name="World control">
+        <ignition-gui>
+          <title>World control</title>
+          <property type="bool" key="showTitleBar">false</property>
+          <property type="bool" key="resizable">false</property>
+          <property type="double" key="height">72</property>
+          <property type="double" key="width">121</property>
+          <property type="double" key="z">1</property>
+
+          <property type="string" key="state">floating</property>
+          <anchors target="3D View">
+            <line own="left" target="left"/>
+            <line own="bottom" target="bottom"/>
+          </anchors>
+        </ignition-gui>
+
+        <play_pause>true</play_pause>
+        <step>true</step>
+        <start_paused>true</start_paused>
+
+      </plugin>
+
+      <!-- World statistics -->
+      <plugin filename="WorldStats" name="World stats">
+        <ignition-gui>
+          <title>World stats</title>
+          <property type="bool" key="showTitleBar">false</property>
+          <property type="bool" key="resizable">false</property>
+          <property type="double" key="height">110</property>
+          <property type="double" key="width">290</property>
+          <property type="double" key="z">1</property>
+
+          <property type="string" key="state">floating</property>
+          <anchors target="3D View">
+            <line own="right" target="right"/>
+            <line own="bottom" target="bottom"/>
+          </anchors>
+        </ignition-gui>
+
+        <sim_time>true</sim_time>
+        <real_time>true</real_time>
+        <real_time_factor>true</real_time_factor>
+        <iterations>true</iterations>
+      </plugin>
+
+      <!-- Inspector -->
+      <plugin filename="ComponentInspector" name="Component inspector">
+        <ignition-gui>
+          <property type="string" key="state">docked_collapsed</property>
+        </ignition-gui>
+      </plugin>
+
+      <!-- Entity tree -->
+      <plugin filename="EntityTree" name="Entity tree">
+        <ignition-gui>
+          <property type="string" key="state">docked_collapsed</property>
+        </ignition-gui>
+      </plugin>
+
+      <plugin filename="ImageDisplay" name="Image Display">
+        <ignition-gui>
+          <title>Vehicle camera</title>
+          <property key="state" type="string">docked</property>
+        </ignition-gui>
+        <topic>camera</topic>
+        <topic_picker>false</topic_picker>
+      </plugin>
+
+      <!-- Translate / rotate -->
+      <plugin filename="TransformControl" name="Transform control">
+        <ignition-gui>
+          <title>Transform control</title>
+          <anchors target="3D View">
+            <line own="left" target="left"/>
+            <line own="top" target="top"/>
+          </anchors>
+          <property key="resizable" type="bool">false</property>
+          <property key="width" type="double">230</property>
+          <property key="height" type="double">50</property>
+          <property key="state" type="string">floating</property>
+          <property key="showTitleBar" type="bool">false</property>
+          <property key="cardBackground" type="string">#666666</property>
+        </ignition-gui>
+      </plugin>
+
+      <!-- Insert simple shapes -->
+      <plugin filename="Shapes" name="Shapes">
+        <ignition-gui>
+          <anchors target="Transform control">
+            <line own="left" target="right"/>
+            <line own="top" target="top"/>
+          </anchors>
+          <property key="resizable" type="bool">false</property>
+          <property key="width" type="double">200</property>
+          <property key="height" type="double">50</property>
+          <property key="state" type="string">floating</property>
+          <property key="showTitleBar" type="bool">false</property>
+          <property key="cardBackground" type="string">#666666</property>
+        </ignition-gui>
+      </plugin>
+
+      <plugin filename="KeyPublisher" name="Key publisher">
+        <ignition-gui>
+          <anchors target="3D View">
+            <line own="right" target="right"/>
+            <line own="top" target="top"/>
+          </anchors>
+          <property key="resizable" type="bool">false</property>
+          <property key="width" type="double">5</property>
+          <property key="height" type="double">5</property>
+          <property key="state" type="string">floating</property>
+          <property key="showTitleBar" type="bool">false</property>
+        </ignition-gui>
+      </plugin>
+    </gui>
+
     <plugin
       filename="ignition-gazebo-physics-system"
       name="ignition::gazebo::systems::Physics">
     </plugin>
+    <plugin
+      filename="ignition-gazebo-sensors-system"
+      name="ignition::gazebo::systems::Sensors">
+      <render_engine>ogre2</render_engine>
+    </plugin>
     <plugin
       filename="ignition-gazebo-user-commands-system"
       name="ignition::gazebo::systems::UserCommands">
@@ -29,21 +173,39 @@
       name="ignition::gazebo::systems::SceneBroadcaster">
     </plugin>
 
-    <!-- The base station / staging area -->
     <include>
       <static>true</static>
-      <name>BaseStation</name>
-      <pose>0 0 0 0 0 0</pose>
+      <name>staging_area</name>
+      <pose>0 0 -0.005 0 0 0</pose>
       <uri>https://fuel.ignitionrobotics.org/1.0/OpenRobotics/models/subt_tunnel_staging_area</uri>
     </include>
 
-    <!-- Fiducial marking the origin for artifacts reports -->
     <include>
-      <name>artifact_origin</name>
-      <pose>2 4 0.5 0 0 0</pose>
-      <uri>https://fuel.ignitionrobotics.org/1.0/OpenRobotics/models/Fiducial</uri>
+      <pose>9.23 2.18 0 0 0 -1.226</pose>
+      <uri>
+        https://fuel.ignitionrobotics.org/1.0/chapulina/models/Extinguisher PBR
+      </uri>
     </include>
 
+    <light name="spotlight" type="spot">
+      <pose>0 0 5 0 0 0</pose>
+      <attenuation>
+        <range>6</range>
+        <linear>0.2</linear>
+        <constant>0.1</constant>
+        <quadratic>0.0025</quadratic>
+      </attenuation>
+      <diffuse>0.8 0.8 0.5 1</diffuse>
+      <specular>0.8 0.8 0.5 1</specular>
+      <spot>
+        <inner_angle>1</inner_angle>
+        <outer_angle>1.1</outer_angle>
+        <falloff>1</falloff>
+      </spot>
+      <direction>0 0 -1</direction>
+      <cast_shadows>1</cast_shadows>
+    </light>
+
     <!-- Tunnel tiles and artifacts -->
     <include>
       <name>tile_0</name>
@@ -896,16 +1058,593 @@
       <uri>https://fuel.ignitionrobotics.org/1.0/OpenRobotics/models/Tunnel Tile 2</uri>
       <pose>280.000000 -240.000000 -10.000000 0 0 3.141593</pose>
     </include>
-
-    <include>
-      <name>x1</name>
-      <uri>https://fuel.ignitionrobotics.org/1.0/OpenRobotics/models/X1 UGV</uri>
-      <pose>0 0 .2 0 0 0</pose>
-    </include>
+    <model name="vehicle">
+        <link name="base_link">
+            <inertial>
+                <pose>0.002225 0.033355 0.022792 0 -0 0</pose>
+                <mass>111.0015</mass>
+                <inertia>
+                    <ixx>4.49753</ixx>
+                    <ixy>0.00199937</ixy>
+                    <ixz>-0.00152659</ixz>
+                    <iyy>2.46329</iyy>
+                    <iyz>-0.424901</iyz>
+                    <izz>5.57714</izz>
+                </inertia>
+            </inertial>
+            <collision name="base_link_collision">
+                <pose>0.25 0 0.0480 0 0 0</pose>
+                <geometry>
+                    <box>
+                        <size>0.6 0.55 0.428</size>
+                    </box>
+                </geometry>
+            </collision>
+            <collision name="base_link_fixed_joint_lump__sensor_payload_link_collision_1">
+                <pose>0.38 0 0.4 0 0 0</pose>
+                <geometry>
+                    <box>
+                        <size>0.28 0.28 0.4</size>
+                    </box>
+                </geometry>
+            </collision>
+            <visual name="connection_visual">
+                <pose>0 0 0 0 1.5707 0</pose>
+                <geometry>
+                    <cylinder>
+                        <length>0.5</length>
+                        <radius>0.05</radius>
+                    </cylinder>
+                </geometry>
+            </visual>
+            <visual name="base_link_visual">
+                <pose>0.180 0 .24 0 0 -1.5707963267948966</pose>
+                <geometry>
+                    <mesh>
+                        <uri>https://fuel.ignitionrobotics.org/1.0/OpenRobotics/models/EXPLORER_R2_SENSOR_CONFIG_2/3/files/meshes/r2.dae</uri>
+                        <submesh>
+                            <name>BodyFront</name>
+                            <center>true</center>
+                        </submesh>
+                    </mesh>
+                </geometry>
+                <material>
+                    <diffuse>1.0 1.0 1.0</diffuse>
+                    <specular>1.0 1.0 1.0</specular>
+                    <pbr>
+                        <metal>
+                            <albedo_map>https://fuel.ignitionrobotics.org/1.0/OpenRobotics/models/EXPLORER_R2_SENSOR_CONFIG_2/3/files/materials/textures/R2_Albedo.png</albedo_map>
+                            <metalness_map>https://fuel.ignitionrobotics.org/1.0/OpenRobotics/models/EXPLORER_R2_SENSOR_CONFIG_2/3/files/materials/textures/R2_Metalness.png</metalness_map>
+                            <roughness_map>https://fuel.ignitionrobotics.org/1.0/OpenRobotics/models/EXPLORER_R2_SENSOR_CONFIG_2/3/files/materials/textures/R2_Roughness.png</roughness_map>
+                        </metal>
+                    </pbr>
+                </material>
+            </visual>
+            <light name="front_light" type="spot">
+                <pose frame="">0.49 0 0.45 1.5707963267948966 1.5707963267948966 -1.5707963267948966</pose>
+                <attenuation>
+                    <range>50</range>
+                    <linear>0</linear>
+                    <constant>0.1</constant>
+                    <quadratic>0.0025</quadratic>
+                </attenuation>
+                <diffuse>0.8 0.8 0.5 1</diffuse>
+                <specular>0.8 0.8 0.5 1</specular>
+                <spot>
+                    <inner_angle>1</inner_angle>
+                    <outer_angle>1.1</outer_angle>
+                    <falloff>1</falloff>
+                </spot>
+                <direction>0 -1 0</direction>
+                <cast_shadows>1</cast_shadows>
+            </light>
+        <sensor name="camera" type="camera">
+          <pose>0.55 0 0.33 0 0 0</pose>
+          <camera>
+            <horizontal_fov>1.047</horizontal_fov>
+            <image>
+              <width>320</width>
+              <height>240</height>
+            </image>
+            <clip>
+              <near>0.1</near>
+              <far>100</far>
+            </clip>
+          </camera>
+          <always_on>1</always_on>
+          <update_rate>30</update_rate>
+          <visualize>true</visualize>
+          <topic>camera</topic>
+        </sensor>
+        </link>
+        <link name="Rear_Rocker_Link">
+            <pose>-0.047625 0 -0.0254 1.5707963267948966 0 0</pose>
+            <inertial>
+                <pose>-0.191018 -0.006403 -0 0 -0 0</pose>
+                <mass>42.8393</mass>
+                <inertia>
+                    <ixx>0.848992</ixx>
+                    <ixy>0.00301842</ixy>
+                    <ixz>5.21788e-06</ixz>
+                    <iyy>1.03049</iyy>
+                    <iyz>1.2171e-07</iyz>
+                    <izz>0.43679</izz>
+                </inertia>
+            </inertial>
+            <collision name="Rear_Rocker_Link_collision">
+                <pose>-0.2 0.072 0 0 0 0</pose>
+                <geometry>
+                    <box>
+                        <size>0.42 0.43 0.56</size>
+                    </box>
+                </geometry>
+            </collision>
+            <collision name="Rear_Rocker_Link_platform_collision1">
+                <pose>-0.70 0.2855 0 -0.005 0 0</pose>
+                <geometry>
+                    <box>
+                        <size>0.17 0.01 0.5</size>
+                    </box>
+                </geometry>
+            </collision>
+            <collision name="Rear_Rocker_Link_platform_collision2">
+                <pose>-0.35 0.2855 -0.005 -0.005 0 0</pose>
+                <geometry>
+                    <box>
+                        <size>0.678 0.01 0.69</size>
+                    </box>
+                </geometry>
+            </collision>
+            <visual name="BodyRear_visual">
+                <pose>-0.428 0.068 0 -1.5707963267948966 -1.5707963267948966 0</pose>
+                <geometry>
+                    <mesh>
+                        <uri>https://fuel.ignitionrobotics.org/1.0/OpenRobotics/models/EXPLORER_R2_SENSOR_CONFIG_2/3/files/meshes/r2.dae</uri>
+                        <submesh>
+                            <name>BodyRear</name>
+                            <center>true</center>
+                        </submesh>
+                    </mesh>
+                </geometry>
+                <material>
+                    <diffuse>1.0 1.0 1.0</diffuse>
+                    <specular>1.0 1.0 1.0</specular>
+                    <pbr>
+                        <metal>
+                            <albedo_map>https://fuel.ignitionrobotics.org/1.0/OpenRobotics/models/EXPLORER_R2_SENSOR_CONFIG_2/3/files/materials/textures/R2_Albedo.png</albedo_map>
+                            <metalness_map>https://fuel.ignitionrobotics.org/1.0/OpenRobotics/models/EXPLORER_R2_SENSOR_CONFIG_2/3/files/materials/textures/R2_Metalness.png</metalness_map>
+                            <roughness_map>https://fuel.ignitionrobotics.org/1.0/OpenRobotics/models/EXPLORER_R2_SENSOR_CONFIG_2/3/files/materials/textures/R2_Roughness.png</roughness_map>
+                        </metal>
+                    </pbr>
+                </material>
+            </visual>
+        </link>
+        <joint name="Center Pivot" type="revolute">
+            <child>Rear_Rocker_Link</child>
+            <parent>base_link</parent>
+            <axis>
+                <xyz>-1 0 0</xyz>
+                <limit>
+                    <lower>-0.5236</lower>
+                    <upper>0.5236</upper>
+                </limit>
+                <dynamics>
+                    <damping>10</damping>
+                    <friction>0.1</friction>
+                    <spring_reference>0.1</spring_reference>
+                    <spring_stiffness>100</spring_stiffness>
+                </dynamics>
+                <use_parent_model_frame>0</use_parent_model_frame>
+            </axis>
+        </joint>
+        <link name="left_front_wheel_link">
+            <pose>0.33421 0.363 -0.091538 -0.013747 -0 -1.5707963267948966</pose>
+            <inertial>
+                <pose>0.007124 -1.6e-05 4e-06 0 -0 0</pose>
+                <mass>11.5398</mass>
+                <inertia>
+                    <ixx>0.127932</ixx>
+                    <ixy>6.41777e-06</ixy>
+                    <ixz>2.40271e-06</ixz>
+                    <iyy>0.0695645</iyy>
+                    <iyz>1.35439e-09</iyz>
+                    <izz>0.0695643</izz>
+                </inertia>
+            </inertial>
+            <collision name="left_front_wheel_link_collision">
+                <pose>0 0 0 3.1415926535897931 1.5707963267948966 3.1415926535897931</pose>
+                <geometry>
+                    <cylinder>
+                        <length>0.1125</length>
+                        <radius>0.31</radius>
+                    </cylinder>
+                </geometry>
+                <surface>
+                    <friction>
+                        <ode>
+                            <mu>0.5</mu>
+                            <mu2>1</mu2>
+                            <fdir1>0 0 1</fdir1>
+                            <slip1>0.0000235</slip1>
+                            <slip2>0</slip2>
+                            <max_vel>10</max_vel>
+                            <min_depth>0.1</min_depth>
+                        </ode>
+                    </friction>
+                    <contact>
+                        <ode>
+                            <kp>1e+07</kp>
+                            <kd>0.0001</kd>
+                        </ode>
+                    </contact>
+                </surface>
+            </collision>
+            <visual name="left_front_wheel_link_visual">
+                <geometry>
+                    <mesh>
+                        <uri>https://fuel.ignitionrobotics.org/1.0/OpenRobotics/models/EXPLORER_R2_SENSOR_CONFIG_2/3/files/meshes/r2.dae</uri>
+                        <submesh>
+                            <name>WheelFL</name>
+                            <center>true</center>
+                        </submesh>
+                    </mesh>
+                </geometry>
+                <material>
+                    <diffuse>1.0 1.0 1.0</diffuse>
+                    <specular>1.0 1.0 1.0</specular>
+                    <pbr>
+                        <metal>
+                            <albedo_map>https://fuel.ignitionrobotics.org/1.0/OpenRobotics/models/EXPLORER_R2_SENSOR_CONFIG_2/3/files/materials/textures/R2_Albedo.png</albedo_map>
+                            <metalness_map>https://fuel.ignitionrobotics.org/1.0/OpenRobotics/models/EXPLORER_R2_SENSOR_CONFIG_2/3/files/materials/textures/R2_Metalness.png</metalness_map>
+                            <roughness_map>https://fuel.ignitionrobotics.org/1.0/OpenRobotics/models/EXPLORER_R2_SENSOR_CONFIG_2/3/files/materials/textures/R2_Roughness.png</roughness_map>
+                        </metal>
+                    </pbr>
+                </material>
+            </visual>
+        </link>
+        <joint name="left_front_wheel" type="revolute">
+            <child>left_front_wheel_link</child>
+            <parent>base_link</parent>
+            <axis>
+                <xyz>-1 0 0</xyz>
+                <limit>
+                    <lower>-1e+16</lower>
+                    <upper>1e+16</upper>
+                </limit>
+                <dynamics>
+                    <damping>10</damping>
+                    <friction>0.1</friction>
+                    <spring_reference>0</spring_reference>
+                    <spring_stiffness>0</spring_stiffness>
+                </dynamics>
+                <use_parent_model_frame>0</use_parent_model_frame>
+            </axis>
+        </joint>
+        <link name="left_rear_wheel_link">
+            <pose>-0.334625 0.363 -0.083399 -0.014389 0.000148 -1.5707963267948966</pose>
+            <inertial>
+                <pose>0.007124 -1.6e-05 4e-06 0 -0 0</pose>
+                <mass>11.5398</mass>
+                <inertia>
+                    <ixx>0.127932</ixx>
+                    <ixy>6.41777e-06</ixy>
+                    <ixz>2.40271e-06</ixz>
+                    <iyy>0.0695645</iyy>
+                    <iyz>1.35439e-09</iyz>
+                    <izz>0.0695643</izz>
+                </inertia>
+            </inertial>
+            <collision name="left_rear_wheel_link_collision">
+                <pose>0 0 0 3.1415926535897931 1.5707963267948966 3.1415926535897931</pose>
+                <geometry>
+                    <cylinder>
+                        <length>0.1125</length>
+                        <radius>0.31</radius>
+                    </cylinder>
+                </geometry>
+                <surface>
+                    <friction>
+                        <ode>
+                            <mu>0.5</mu>
+                            <mu2>1</mu2>
+                            <fdir1>0 0 1</fdir1>
+                            <slip1>0.0000235</slip1>
+                            <slip2>0</slip2>
+                            <max_vel>10</max_vel>
+                            <min_depth>0.1</min_depth>
+                        </ode>
+                    </friction>
+                    <contact>
+                        <ode>
+                            <kp>1e+07</kp>
+                            <kd>0.0001</kd>
+                        </ode>
+                    </contact>
+                </surface>
+            </collision>
+            <visual name="left_rear_wheel_link_visual">
+                <geometry>
+                    <mesh>
+                        <uri>https://fuel.ignitionrobotics.org/1.0/OpenRobotics/models/EXPLORER_R2_SENSOR_CONFIG_2/3/files/meshes/r2.dae</uri>
+                        <submesh>
+                            <name>WheelBL</name>
+                            <center>true</center>
+                        </submesh>
+                    </mesh>
+                </geometry>
+                <material>
+                    <diffuse>1.0 1.0 1.0</diffuse>
+                    <specular>1.0 1.0 1.0</specular>
+                    <pbr>
+                        <metal>
+                            <albedo_map>https://fuel.ignitionrobotics.org/1.0/OpenRobotics/models/EXPLORER_R2_SENSOR_CONFIG_2/3/files/materials/textures/R2_Albedo.png</albedo_map>
+                            <metalness_map>https://fuel.ignitionrobotics.org/1.0/OpenRobotics/models/EXPLORER_R2_SENSOR_CONFIG_2/3/files/materials/textures/R2_Metalness.png</metalness_map>
+                            <roughness_map>https://fuel.ignitionrobotics.org/1.0/OpenRobotics/models/EXPLORER_R2_SENSOR_CONFIG_2/3/files/materials/textures/R2_Roughness.png</roughness_map>
+                        </metal>
+                    </pbr>
+                </material>
+            </visual>
+        </link>
+        <joint name="left_rear_wheel" type="revolute">
+            <child>left_rear_wheel_link</child>
+            <parent>Rear_Rocker_Link</parent>
+            <axis>
+                <xyz>-1 0 0</xyz>
+                <limit>
+                    <lower>-1e+16</lower>
+                    <upper>1e+16</upper>
+                </limit>
+                <dynamics>
+                    <damping>10</damping>
+                    <friction>0.1</friction>
+                    <spring_reference>0</spring_reference>
+                    <spring_stiffness>0</spring_stiffness>
+                </dynamics>
+                <use_parent_model_frame>0</use_parent_model_frame>
+            </axis>
+        </joint>
+        <link name="right_front_wheel_link">
+            <pose>0.33421 -0.363 -0.091538 -0.013747 -0 1.5707963267948966</pose>
+            <inertial>
+                <pose>0.007124 -1.6e-05 4e-06 0 -0 0</pose>
+                <mass>11.5398</mass>
+                <inertia>
+                    <ixx>0.127932</ixx>
+                    <ixy>6.41777e-06</ixy>
+                    <ixz>2.40271e-06</ixz>
+                    <iyy>0.0695645</iyy>
+                    <iyz>1.35439e-09</iyz>
+                    <izz>0.0695643</izz>
+                </inertia>
+            </inertial>
+            <collision name="right_front_wheel_link_collision">
+                <pose>0 0 0 3.1415926535897931 1.5707963267948966 3.1415926535897931</pose>
+                <geometry>
+                    <cylinder>
+                        <length>0.1125</length>
+                        <radius>0.31</radius>
+                    </cylinder>
+                </geometry>
+                <surface>
+                    <friction>
+                        <ode>
+                            <mu>0.5</mu>
+                            <mu2>1</mu2>
+                            <fdir1>0 0 1</fdir1>
+                            <slip1>0.0000235</slip1>
+                            <slip2>0</slip2>
+                            <max_vel>10</max_vel>
+                            <min_depth>0.1</min_depth>
+                        </ode>
+                    </friction>
+                    <contact>
+                        <ode>
+                            <kp>1e+07</kp>
+                            <kd>0.0001</kd>
+                        </ode>
+                    </contact>
+                </surface>
+            </collision>
+            <visual name="right_front_wheel_link_visual">
+                <geometry>
+                    <mesh>
+                        <uri>https://fuel.ignitionrobotics.org/1.0/OpenRobotics/models/EXPLORER_R2_SENSOR_CONFIG_2/3/files/meshes/r2.dae</uri>
+                        <submesh>
+                            <name>WheelFR</name>
+                            <center>true</center>
+                        </submesh>
+                    </mesh>
+                </geometry>
+                <material>
+                    <diffuse>1.0 1.0 1.0</diffuse>
+                    <specular>1.0 1.0 1.0</specular>
+                    <pbr>
+                        <metal>
+                            <albedo_map>https://fuel.ignitionrobotics.org/1.0/OpenRobotics/models/EXPLORER_R2_SENSOR_CONFIG_2/3/files/materials/textures/R2_Albedo.png</albedo_map>
+                            <metalness_map>https://fuel.ignitionrobotics.org/1.0/OpenRobotics/models/EXPLORER_R2_SENSOR_CONFIG_2/3/files/materials/textures/R2_Metalness.png</metalness_map>
+                            <roughness_map>https://fuel.ignitionrobotics.org/1.0/OpenRobotics/models/EXPLORER_R2_SENSOR_CONFIG_2/3/files/materials/textures/R2_Roughness.png</roughness_map>
+                        </metal>
+                    </pbr>
+                </material>
+            </visual>
+        </link>
+        <joint name="right_front_wheel" type="revolute">
+            <child>right_front_wheel_link</child>
+            <parent>base_link</parent>
+            <axis>
+                <xyz>1 0 0</xyz>
+                <limit>
+                    <lower>-1e+16</lower>
+                    <upper>1e+16</upper>
+                </limit>
+                <dynamics>
+                    <damping>10</damping>
+                    <friction>0.1</friction>
+                    <spring_reference>0</spring_reference>
+                    <spring_stiffness>0</spring_stiffness>
+                </dynamics>
+                <use_parent_model_frame>0</use_parent_model_frame>
+            </axis>
+        </joint>
+        <link name="right_rear_wheel_link">
+            <pose>-0.334625 -0.363 -0.083401 -0.014389 -0.000148 1.5707963267948966</pose>
+            <inertial>
+                <pose>0.007124 -1.6e-05 4e-06 0 -0 0</pose>
+                <mass>11.5398</mass>
+                <inertia>
+                    <ixx>0.127932</ixx>
+                    <ixy>6.41777e-06</ixy>
+                    <ixz>2.40271e-06</ixz>
+                    <iyy>0.0695645</iyy>
+                    <iyz>1.35439e-09</iyz>
+                    <izz>0.0695643</izz>
+                </inertia>
+            </inertial>
+            <collision name="right_rear_wheel_link_collision">
+                <pose>0 0 0 3.1415926535897931 1.5707963267948966 3.1415926535897931</pose>
+                <geometry>
+                    <cylinder>
+                        <length>0.1125</length>
+                        <radius>0.31</radius>
+                    </cylinder>
+                </geometry>
+                <surface>
+                    <friction>
+                        <ode>
+                            <mu>0.5</mu>
+                            <mu2>1</mu2>
+                            <fdir1>0 0 1</fdir1>
+                            <slip1>0.0000235</slip1>
+                            <slip2>0</slip2>
+                            <max_vel>10</max_vel>
+                            <min_depth>0.1</min_depth>
+                        </ode>
+                    </friction>
+                    <contact>
+                        <ode>
+                            <kp>1e+07</kp>
+                            <kd>0.0001</kd>
+                        </ode>
+                    </contact>
+                </surface>
+            </collision>
+            <visual name="right_rear_wheel_link_visual">
+                <geometry>
+                    <mesh>
+                        <uri>https://fuel.ignitionrobotics.org/1.0/OpenRobotics/models/EXPLORER_R2_SENSOR_CONFIG_2/3/files/meshes/r2.dae</uri>
+                        <submesh>
+                            <name>WheelBR</name>
+                            <center>true</center>
+                        </submesh>
+                    </mesh>
+                </geometry>
+                <material>
+                    <diffuse>1.0 1.0 1.0</diffuse>
+                    <specular>1.0 1.0 1.0</specular>
+                    <pbr>
+                        <metal>
+                            <albedo_map>https://fuel.ignitionrobotics.org/1.0/OpenRobotics/models/EXPLORER_R2_SENSOR_CONFIG_2/3/files/materials/textures/R2_Albedo.png</albedo_map>
+                            <metalness_map>https://fuel.ignitionrobotics.org/1.0/OpenRobotics/models/EXPLORER_R2_SENSOR_CONFIG_2/3/files/materials/textures/R2_Metalness.png</metalness_map>
+                            <roughness_map>https://fuel.ignitionrobotics.org/1.0/OpenRobotics/models/EXPLORER_R2_SENSOR_CONFIG_2/3/files/materials/textures/R2_Roughness.png</roughness_map>
+                        </metal>
+                    </pbr>
+                </material>
+            </visual>
+        </link>
+        <joint name="right_rear_wheel" type="revolute">
+            <child>right_rear_wheel_link</child>
+            <parent>Rear_Rocker_Link</parent>
+            <axis>
+                <xyz>1 0 0</xyz>
+                <limit>
+                    <lower>-1e+16</lower>
+                    <upper>1e+16</upper>
+                </limit>
+                <dynamics>
+                    <damping>10</damping>
+                    <friction>0.1</friction>
+                    <spring_reference>0</spring_reference>
+                    <spring_stiffness>0</spring_stiffness>
+                </dynamics>
+                <use_parent_model_frame>0</use_parent_model_frame>
+            </axis>
+        </joint>
+
+      <pose>0 0 0.38 0 0 0.0</pose>
+
+      <plugin
+        filename="ignition-gazebo-diff-drive-system"
+        name="ignition::gazebo::systems::DiffDrive">
+        <left_joint>left_rear_wheel</left_joint>
+        <left_joint>left_front_wheel</left_joint>
+        <right_joint>right_rear_wheel</right_joint>
+        <right_joint>right_front_wheel</right_joint>
+        <wheel_separation>1.25</wheel_separation>
+        <wheel_radius>0.3</wheel_radius>
+        <odom_publish_frequency>1</odom_publish_frequency>
+        <topic>cmd_vel</topic>
+      </plugin>
+
+      <!-- Moving Forward: W -->
+      <plugin filename="libignition-gazebo-triggered-publisher-system.so"
+              name="ignition::gazebo::systems::TriggeredPublisher">
+          <input type="ignition.msgs.Int32" topic="/keyboard/keypress">
+              <match field="data">87</match>
+          </input>
+          <output type="ignition.msgs.Twist" topic="/cmd_vel">
+              linear: {x: 2.0}, angular: {z: 0.0}
+          </output>
+      </plugin>
+
+      <!-- Moving Backward: X -->
+      <plugin filename="libignition-gazebo-triggered-publisher-system.so"
+              name="ignition::gazebo::systems::TriggeredPublisher">
+          <input type="ignition.msgs.Int32" topic="/keyboard/keypress">
+              <match field="data">88</match>
+          </input>
+          <output type="ignition.msgs.Twist" topic="/cmd_vel">
+              linear: {x: -2.0}, angular: {z: 0.0}
+          </output>
+      </plugin>
+
+      <!-- Rotating right: D -->
+      <plugin filename="libignition-gazebo-triggered-publisher-system.so"
+              name="ignition::gazebo::systems::TriggeredPublisher">
+          <input type="ignition.msgs.Int32" topic="/keyboard/keypress">
+              <match field="data">68</match>
+          </input>
+          <output type="ignition.msgs.Twist" topic="/cmd_vel">
+              linear: {x: 0.0}, angular: {z: -0.5}
+          </output>
+      </plugin>
+
+      <!--Rotating left: A -->
+      <plugin filename="libignition-gazebo-triggered-publisher-system.so"
+              name="ignition::gazebo::systems::TriggeredPublisher">
+          <input type="ignition.msgs.Int32" topic="/keyboard/keypress">
+              <match field="data">65</match>
+          </input>
+          <output type="ignition.msgs.Twist" topic="/cmd_vel">
+              linear: {x: 0.0}, angular: {z: 0.5}
+          </output>
+      </plugin>
+
+      <!--Stop: S -->
+      <plugin filename="libignition-gazebo-triggered-publisher-system.so"
+              name="ignition::gazebo::systems::TriggeredPublisher">
+          <input type="ignition.msgs.Int32" topic="/keyboard/keypress">
+              <match field="data">83</match>
+          </input>
+          <output type="ignition.msgs.Twist" topic="/cmd_vel">
+              linear: {x: 0.0}, angular: {z: 0.0}
+          </output>
+      </plugin>
+
+    </model>
 
     <plugin name="ignition::gazebo" filename="dummy">
       <performer name="perf_x1">
-        <ref>x1</ref>
+        <ref>vehicle</ref>
         <geometry><box><size>2 2 2</size></box></geometry>
       </performer>
 
diff --git a/src/Conversions.cc b/src/Conversions.cc
index cc2d685861..edbc024d77 100644
--- a/src/Conversions.cc
+++ b/src/Conversions.cc
@@ -264,6 +264,12 @@ msgs::Material ignition::gazebo::convert(const sdf::Material &_in)
   msgs::Set(out.mutable_emissive(), _in.Emissive());
   out.set_lighting(_in.Lighting());
 
+  // todo(anyone) add double_sided field to msgs::Material
+  auto data = out.mutable_header()->add_data();
+  data->set_key("double_sided");
+  std::string *value = data->add_value();
+  *value = std::to_string(_in.DoubleSided());
+
   sdf::Pbr *pbr = _in.PbrMaterial();
   if (pbr)
   {
@@ -317,6 +323,14 @@ sdf::Material ignition::gazebo::convert(const msgs::Material &_in)
   out.SetEmissive(msgs::Convert(_in.emissive()));
   out.SetLighting(_in.lighting());
 
+  // todo(anyone) add double_sided field to msgs::Material
+  for (int i = 0; i < _in.header().data_size(); ++i)
+  {
+    const auto &data = _in.header().data(i);
+    if (data.key() == "double_sided" && data.value_size() > 0)
+      out.SetDoubleSided(math::parseInt(data.value(0)));
+  }
+
   if (_in.has_pbr())
   {
     const auto &pbrMsg = _in.pbr();
diff --git a/src/Conversions_TEST.cc b/src/Conversions_TEST.cc
index 8ce78db565..fe155e00a5 100644
--- a/src/Conversions_TEST.cc
+++ b/src/Conversions_TEST.cc
@@ -206,6 +206,9 @@ TEST(Conversions, Material)
   material.SetEmissive(ignition::math::Color(1.3f, 1.4f, 1.5f, 1.6f));
   material.SetLighting(true);
 
+  // todo(anyone) add double_sided field to msgs::Material
+  material.SetDoubleSided(true);
+
   sdf::Pbr pbr;
   sdf::PbrWorkflow workflow;
   workflow.SetType(sdf::PbrWorkflowType::METAL);
@@ -235,6 +238,11 @@ TEST(Conversions, Material)
       msgs::Convert(materialMsg.emissive()));
   EXPECT_TRUE(materialMsg.lighting());
 
+  // todo(anyone) double_sided is temporarily stored in header
+  // Need to add double_sided field to msgs::Material
+  bool doubleSided = math::parseInt(materialMsg.header().data(0).value(0));
+  EXPECT_TRUE(doubleSided);
+
   EXPECT_TRUE(materialMsg.has_pbr());
   const auto &pbrMsg = materialMsg.pbr();
   EXPECT_EQ(msgs::Material_PBR_WorkflowType_METAL, pbrMsg.type());
@@ -257,6 +265,7 @@ TEST(Conversions, Material)
   EXPECT_EQ(math::Color(0.9f, 1.0f, 1.1f, 1.2f), newMaterial.Ambient());
   EXPECT_EQ(math::Color(1.3f, 1.4f, 1.5f, 1.6f), newMaterial.Emissive());
   EXPECT_TRUE(newMaterial.Lighting());
+  EXPECT_TRUE(newMaterial.DoubleSided());
 
   sdf::Pbr *newPbrMaterial = newMaterial.PbrMaterial();
   ASSERT_NE(nullptr, newPbrMaterial);
diff --git a/src/rendering/SceneManager.cc b/src/rendering/SceneManager.cc
index 6bfa86f924..54fb330aa9 100644
--- a/src/rendering/SceneManager.cc
+++ b/src/rendering/SceneManager.cc
@@ -492,7 +492,7 @@ rendering::MaterialPtr SceneManager::LoadMaterial(
       {
         material->SetTexture(fullPath);
         // Use alpha channel for transparency
-        material->SetAlphaFromTexture(true);
+        material->SetAlphaFromTexture(true, 0.5, _material.DoubleSided());
       }
       else
         ignerr << "Unable to find file [" << albedoMap << "]\n";