anki-3d-engine/ThirdParty/Bullet/data/sphere_with_restitution.urdf

<?xml version="0.0" ?>
<robot name="urdf_robot">
  <link name="baseLink">
  	<contact>
      <restitution value="0.5" />
      <rolling_friction value="0.001"/>
      <spinning_friction value="0.001"/>
      
    </contact>

    <inertial>
      <origin rpy="0 0 0" xyz="0 0 0"/>
       <mass value="10.0"/>
       <inertia ixx="1" ixy="0" ixz="0" iyy="1" iyz="0" izz="1"/>
    </inertial>
    <visual>
      <origin rpy="0 0 0" xyz="0 0 0"/>
      <geometry>
				<mesh filename="textured_sphere_smooth.obj" scale="0.5 0.5 0.5"/>      
      </geometry>
      <material name="white">
        <color rgba="1 1 1 1"/>
      </material>
    </visual>
    <collision>
      <origin rpy="0 0 0" xyz="0 0 0"/>
      <geometry>
	 <sphere radius="0.5"/>
      </geometry>
    </collision>
  </link>
</robot>