Solve the problem of abnormal display of urdf model in gazebo, display model in rviz

Previously used roslaunch to load the urdf model into the rosparam parameter server

In rviz, the color of the model is displayed normally, while in gazebo, it is displayed in white.

The correct solution is:

The properties of the materials are defined in a separate file materials.xacro

<?xml version="1.0"?>

<!-- 
These are some material descriptions of the Pioneer 3DX.
Copyright (C) 2013 Rafael Berkvens [email protected]

This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program.  If not, see <http://www.gnu.org/licenses/>.

This project is based on work by Tracy Davies, where it was in turn based on
work original in ucs-ros-pkg.-->
<robot>
  <material name="black">
    <color rgba="0.0 0.0 0.0 1.0"/>
  </material>

  <material name="blue">
    <color rgba="0.0 0.0 0.8 1.0"/>
  </material>

  <material name="green">
    <color rgba="0.0 0.8 0.0 1.0"/>
  </material>

  <material name="gray">
    <color rgba="0.7 0.7 0.7 1.0"/>
  </material>

  <material name="darkgray">
    <color rgba="0.3 0.3 0.3 1.0"/>
  </material>

  <material name="red">
    <color rgba="0.8 0.0 0.0 1.0"/>
  </material>

  <material name="white">
    <color rgba="1.0 1.0 1.0 1.0"/>
  </material>

  <material name="yellow">
    <color rgba="0.8 0.8 0.0 1.0"/>
  </material>

</robot>

Modify the reference material in pxdx.xacro, pay attention to delete the name in the visual, otherwise the display is abnormal

<material name="red"/> The visual element is used to define the material

<?xml version="1.0"?>
<!-- 
This is the xacro description of a Pioneer 3DX, to be used in rviz and gazebo.
Copyright (C) 2013 Rafael Berkvens [email protected]

This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program.  If not, see <http://www.gnu.org/licenses/>.

This project is based on work by Tracy Davies, where it was in turn based on
work original in ucs-ros-pkg.-->

<robot name="pxdx" xmlns:xacro="http://www.ros.org/wiki/xacro">

  <!-- import all gazebo-customization elements, including gazebo colors -->
  <xacro:include filename="pxdx.gazebo" />
  <!-- import the pioneer 3dx's wheels -->
  <xacro:include filename="pxdx_wheel.xacro" />
  <xacro:include filename="materials.xacro" />

  <!-- chassis -->
	<link name="base_link">
		<inertial>
			<mass value="3.5" />
			<!--<origin xyz="-0.025 0 -0.223"/> -->
			<origin xyz="-0.05 0 0" />
			<inertia ixx="1" ixy="0" ixz="0" iyy="1" iyz="0" izz="1" />
		</inertial>

		<visual>
			<origin xyz="-0.045 0 0.145" rpy="0 0 0" />
			<geometry name="pioneer_geom">
				<box size="0.35 0.25 0.14" />
			</geometry>
			<material name="red"/>
		</visual>

		<collision>
			<origin xyz="-0.045 0 0.145" rpy="0 0 0" />
			<geometry>
				<box size="0.35 0.25 0.14" />
			</geometry>
		</collision>
	</link>

  <!-- top_plate -->
	<link name="top_plate">
		<inertial>
			<mass value="0.01" />
			<origin xyz="0 0 0" />
			<inertia ixx="0.001" ixy="0" ixz="0" iyy="0.001" iyz="0" izz="0.001" />
		</inertial>

		<visual>
			<origin xyz="0 0 0" rpy="0 0 0" />
			<geometry name="top_geom">
				<box size="0.45 0.38 0.01" />
			</geometry>

			<material name="black"/>
		</visual>

		<collision>
			<origin xyz="0.0 0 0" rpy="0 0 0" />
			<geometry name="pioneer_geom">
				<box size="0.45 0.38 0.01" />
			</geometry>
		</collision>
	</link>

	<joint name="base_top_joint" type="fixed">
		<origin xyz="-0.045 0 0.234" rpy="0 0 0" />
		<parent link="base_link" />
		<child link="top_plate" />
	</joint>

  <!-- swivel -->
	<link name="swivel">
		<inertial>
			<mass value="0.1" />
			<origin xyz="0 0 0" />
			<inertia ixx="0.01" ixy="0" ixz="0" iyy="0.01" iyz="0" izz="0.01" />
		</inertial>

		<visual>
			<origin xyz="0 0 0" rpy="0 0 0" />
			<geometry name="pioneer_geom">
				<box size="0.01 0.01 0.01" />
			</geometry>
			<material name="gray"/>
		</visual>

		<collision>
			<origin xyz="0 0 0" rpy="0 0 0" />
			<geometry>
				<box size="0.01 0.01 0.01" />
			</geometry>
		</collision>
	</link>

	<joint name="base_swivel_joint" type="continuous">
		<origin xyz="-0.185 0 0.055" rpy="0 0 0" />
		<axis xyz="0 0 1" />
		<anchor xyz="0 0 0" />
		<limit effort="100" velocity="100" k_velocity="0" />
		<joint_properties damping="0.0" friction="0.0" />
		<parent link="base_link" />
		<child link="swivel" />
	</joint>

  <!-- center_hubcap -->
	<link name="center_hubcap">
		<inertial>
			<mass value="0.01" />
			<origin xyz="0 0 0" />
			<inertia ixx="0.012411765597" ixy="-0.000711733678" ixz="0.00050272983"
				iyy="0.015218160428" iyz="-0.000004273467" izz="0.011763977943" />
		</inertial>

		<visual>
			<origin xyz="0 0 0" rpy="0 0 0" />
			<geometry name="pioneer_geom">
				<box size="0.01 0.01 0.01" />
			</geometry>
			<material name="gray"/>
		</visual>

		<collision>
			<origin xyz="0 0 0" rpy="0 0 0" />
			<geometry>
				<box size="0.01 0.01 0.01" />
			</geometry>
		</collision>
	</link>

	<joint name="swivel_hubcap_joint" type="continuous">
		<origin xyz="-0.026 0 -0.016" rpy="0 0 0" />
		<axis xyz="0 1 0" />
		<anchor xyz="0 0 0" />
		<limit effort="100" velocity="100" k_velocity="0" />
		<joint_properties damping="0.0" friction="0.0" />
		<parent link="swivel" />
		<child link="center_wheel" />
	</joint>

  <!-- center_wheel -->
	<link name="center_wheel">
		<inertial>
			<mass value="0.1" />
			<origin xyz="0 0 0" />
			<inertia ixx="0.012411765597" ixy="-0.000711733678" ixz="0.00050272983"
				iyy="0.015218160428" iyz="-0.000004273467" izz="0.011763977943" />
		</inertial>

		<visual>
			<origin xyz="0 0 0" rpy="${-3.1415927/2.0} 0 0" />
			<geometry name="pioneer_geom">
				<cylinder radius="0.0375" length="0.01" />
			</geometry>
			<material name="black"/>

		</visual>

		<collision>
			<origin xyz="0 0 0" rpy="${-3.1415927/2.0} 0 0" />
			<geometry>
				<cylinder radius="0.0375" length="0.01" />
			</geometry>
		</collision>
	</link>

	<joint name="center_wheel_joint" type="fixed">
		<origin xyz="-0.0035 0 -0.001" rpy="0 0 0"/>
		<parent link="center_wheel"/>
		<child link="center_hubcap"/>
	</joint>

	<xacro:p3dx_wheel suffix="left" parent="base_link" reflect="1"/>
	<xacro:p3dx_wheel suffix="right" parent="base_link" reflect="-1"/>
	
	<!-- lms100 laser -->
	<link name="lms100">
		<inertial>
			<mass value="1e-5" />
			<origin xyz="0 0 0" rpy="0 0 0" />
			<inertia ixx="1e-6" ixy="0" ixz="0" iyy="1e-6" iyz="0" izz="1e-6" />
		</inertial>

		<visual>
			<origin xyz="0 0 0" rpy="0 0 0" />
			<geometry>
				<box size="0.1 0.1 0.1" />   
			</geometry>
			<material name="green"/>
		</visual>

		<collision>
			<origin xyz="0 0 0" rpy="0 0 0" />
			<geometry>
				<box size="0.1 0.1 0.1" />
			</geometry>
		</collision>
	</link>

	<joint name="lms100_joint" type="fixed">
		<axis xyz="0 1 0" />
		<origin xyz="0 0 0.25" rpy="0 0 0" />
		<parent link="base_link" />
		<child link="lms100" />
	</joint>

</robot>

Define reference in pxdx.gazebo as the link name, then convert the color to gazebo color, and define others at the same time

<?xml version="1.0"?>

<!-- 
This is the gazebo urdf description of a Pioneer 3DX.
Copyright (C) 2013 Rafael Berkvens [email protected]

This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program.  If not, see <http://www.gnu.org/licenses/>.
 -->
<robot xmlns:xacro="http://www.ros.org/wiki/xacro">
  
  <!-- properties (constants) -->
  <xacro:property name="ns" value="pxdx" />
  <!-- ros_control plugin -->
  <gazebo>
    <plugin name="gazebo_ros_control" filename="libgazebo_ros_control.so">
      <robotNamespace>/${ns}</robotNamespace>
    </plugin>
  </gazebo>

  <!-- base_link -->
	<gazebo reference="base_link">
	  <material>Gazebo/Red</material>
	</gazebo>

  <!-- top_plate -->
  <gazebo reference="top_plate">
    <material>Gazebo/Black</material>
  </gazebo>
  
  <!-- swivel -->
  <gazebo reference="swivel">
	<material>Gazebo/Gray</material>
  </gazebo>
  
  <!-- center_hubcap -->
	<gazebo reference="center_hubcap">
	  <material>Gazebo/Gray</material>
	</gazebo>
  
  <!-- center_wheel -->
	<gazebo reference="center_wheel">
		<material>Gazebo/Black</material>
		<mu1>10.0</mu1>
		<mu2>10.0</mu2>
		<kp>1000000.0</kp>
		<kd>1.0</kd>
	</gazebo>

  <!-- differential drive -->
	<gazebo>
		<plugin name="differential_drive_controller" filename="libgazebo_ros_diff_drive.so">
			<alwaysOn>true</alwaysOn>
            <legacyMode>0</legacyMode>
            <robotNamespace>/${ns}</robotNamespace>
			<updateRate>100</updateRate>
			<leftJoint>base_right_wheel_joint</leftJoint>
			<rightJoint>base_left_wheel_joint</rightJoint>
			<wheelSeparation>0.39</wheelSeparation>
			<wheelDiameter>0.15</wheelDiameter>
            <wheelAcceleration>1.0</wheelAcceleration>
			<wheelTorque>5</wheelTorque>
			<commandTopic>cmd_vel</commandTopic>
			<odometryTopic>odom</odometryTopic>
			<odometryFrame>base_footprint</odometryFrame>
			<robotBaseFrame>base_link</robotBaseFrame>
            <publishWheelTF>0</publishWheelTF>
            <publishOdom>1</publishOdom>
            <publishWheelJointState>0</publishWheelJointState>
		</plugin>
	</gazebo>

  <!-- ground truth -->
	<gazebo>
		<plugin name="p3d_base_controller" filename="libgazebo_ros_p3d.so">
			<alwaysOn>true</alwaysOn>
			<updateRate>50.0</updateRate>
			<bodyName>base_link</bodyName>
			<topicName>base_pose_ground_truth</topicName>
            <robotNamespace>/${ns}</robotNamespace>
			<gaussianNoise>0.01</gaussianNoise>
			<frameName>map</frameName>
			<!-- initialize odometry for fake localization -->
			<xyzOffsets>0 0 0</xyzOffsets>
			<rpyOffsets>0 0 0</rpyOffsets>
		</plugin>
	</gazebo>
	
	<!-- lms100 -->
	<gazebo reference="lms100">
	  <material>Gazebo/Green</material>
		<sensor type="ray" name="head_hokuyo_sensor">
			<pose>0 0 0 0 0 0</pose>
			<visualize>false</visualize>
			<update_rate>10</update_rate>
			<ray>
				<scan>
					<horizontal>
						<samples>360</samples>
						<resolution>1</resolution>
						<min_angle>-3.1415926</min_angle>
						<max_angle>3.1415926</max_angle>
					</horizontal>
				</scan>
				<range>
					<min>0.10</min>
					<max>16.0</max>
					<resolution>0.01</resolution>
				</range>
				<noise>
					<type>gaussian</type>
					<!-- Noise parameters based on published spec for Hokuyo laser achieving 
						"+-30mm" accuracy at range < 10m. A mean of 0.0m and stddev of 0.01m will 
						put 99.7% of samples within 0.03m of the true reading. -->
					<mean>0.0</mean>
					<stddev>0.01</stddev>
				</noise>
			</ray>
			<plugin name="gazebo_ros_head_hokuyo_controller" filename="libgazebo_ros_laser.so">
				<topicName>laser_scan</topicName>
                <robotNamespace>/${ns}</robotNamespace>
				<frameName>lms100</frameName>
			</plugin>
		</sensor>
	</gazebo>
  <gazebo>
        <plugin name="joint_state_publisher" filename="libgazebo_ros_joint_state_publisher.so">
            <jointName>base_right_wheel_joint,base_left_wheel_joint,swivel_hubcap_joint,base_swivel_joint</jointName>
            <robotNamespace>/${ns}</robotNamespace>
        </plugin>
    </gazebo>
</robot>

Specify material in pxdx_wheel.xacro

<?xml version="1.0"?>

<!-- 
This is the xacro description of a wheel of the Pioneer 3DX.
Copyright (C) 2013 Rafael Berkvens [email protected]

This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program.  If not, see <http://www.gnu.org/licenses/>.

This project is based on work by Tracy Davies, where it was in turn based on
work original in ucs-ros-pkg.
 -->

<robot xmlns:xacro="http://www.ros.org/wiki/xacro">
	<!-- properties (constants) -->
	<xacro:property name="M_PI" value="3.14159" />

	<!-- right/left hubcap + wheel -->
	<xacro:macro name="p3dx_wheel" params="suffix parent reflect">
	
		<!-- wheel -->
		<link name="p3dx_${suffix}_wheel">
			<inertial>
				<mass value="0.5" />
				<origin xyz="0 0 0" />
				<inertia ixx="0.012411765597" ixy="0" ixz="0" iyy="0.015218160428"
					iyz="0" izz="0.011763977943" />
			</inertial>

			<visual>
				<origin xyz="0 0 0" rpy="${-3.1415927/2} 0 0" />
				<geometry name="pioneer_geom">
					<cylinder radius="0.09" length="0.01" />
				</geometry>
				<material name="black"/>
			</visual>

			<collision>
				<origin xyz="0 0 0" rpy="${-3.1415927/2} 0 0" />
				<geometry>
					<!--<mesh filename="package://p3dx_description/meshes/${suffix}_wheel.stl"/> -->
					<cylinder radius="0.09" length="0.01" />
				</geometry>
			</collision>
		</link>

		<joint name="base_${suffix}_hubcap_joint" type="fixed">
			<origin xyz="0 0 0" rpy="0 0 0" />
			<parent link="p3dx_${suffix}_wheel" />
			<child link="p3dx_${suffix}_hubcap" />
		</joint>

		<!-- hubcap -->
		<link name="p3dx_${suffix}_hubcap">
			<inertial>
				<mass value="0.01" />
				<origin xyz="0 0 0" />
				<inertia ixx="0.012411765597" ixy="0" ixz="0" iyy="0.015218160428"
					iyz="0" izz="0.011763977943" />
			</inertial>

			<visual>
				<origin xyz="0 0 0" rpy="0 0 0" />
				<geometry name="pioneer_geom">
					<box size="0.01 0.01 0.01" />
				</geometry>
				<material name="yellow"/>
			</visual>

			<collision>
				<origin xyz="0 0 0" rpy="0 0 0" />
				<geometry>
					<box size="0.01 0.01 0.01" />
				</geometry>
			</collision>
		</link>

		<joint name="base_${suffix}_wheel_joint" type="continuous">
			<axis xyz="0 1 0" />
			<anchor xyz="0 0 0" />
			<limit effort="100" velocity="100" />
			<joint_properties damping="0.0" friction="0.0" />
			<origin xyz="0 ${reflect*0.158} 0.091" rpy="0 0 0" />
			<parent link="base_link" />
			<child link="p3dx_${suffix}_wheel" />
		</joint>
		
		<!-- gazebo elements -->

    <transmission name="${parent}_${suffix}_wheel_trans">
      <type>transmission_interface/SimpleTransmission</type>
      <joint name="base_${suffix}_wheel_joint">
        <hardwareInterface>EffortJointInterface</hardwareInterface>
      </joint>
      <actuator name="base_${suffix}_wheel_motor">
        <hardwareInterface>EffortJointInterface</hardwareInterface>
        <mechanicalReduction>${reflect * 624/35 * 80/19}</mechanicalReduction>
      </actuator>
    </transmission>

	<gazebo reference="p3dx_${suffix}_hubcap">
		<material>Gazebo/Yellow</material>
	</gazebo>

	<gazebo reference="p3dx_${suffix}_wheel">
		<material>Gazebo/Black</material>
		<mu1>0.5</mu1>
		<mu2>50.0</mu2>
		<kp>100000000.0</kp>
		<kd>1.0</kd>
	</gazebo>

	</xacro:macro>

</robot>