diff --git a/gz_ros2_control_demos/urdf/test_diff_drive.xacro.urdf b/gz_ros2_control_demos/urdf/test_diff_drive.xacro.urdf
index 7b77b090..fe942fd4 100644
--- a/gz_ros2_control_demos/urdf/test_diff_drive.xacro.urdf
+++ b/gz_ros2_control_demos/urdf/test_diff_drive.xacro.urdf
@@ -1,5 +1,16 @@
 <?xml version="1.0"?>
 <robot name="diff_drive" xmlns:xacro="http://www.ros.org/wiki/xacro">
+  <material name="orange">
+    <color rgba="0.8 0.4 0.0 1.0"/>
+  </material>
+
+  <material name="black">
+    <color rgba="0 0 0 1.0"/>
+  </material>
+
+  <material name="white">
+    <color rgba="1 1 1 1.0"/>
+  </material>
   <!-- Base Link -->
   <link name="chassis">
     <collision>