red_box.urdf

<?xml version="1.0"?>
<robot name="red_box">
  <mujoco>
      <compiler meshdir="./mesh" balanceinertia="false"/>
  </mujoco>

  <link name="object_link">
    <visual>
      <origin xyz="0 0 0" rpy="0 0 0"/>
      <geometry>
        <box size="0.3015 0.149 0.0796"/>
      </geometry>
    </visual>
    <collision>
      <origin xyz="0 0 0" rpy="0 0 0"/>
      <geometry>
        <box size="0.3015 0.149 0.0796"/>
      </geometry>
    </collision>
    <inertial>
      <origin xyz="0 0 0" rpy="0 0 0"/>
      <mass value="0.155"/>
      <inertia ixx="0.0003686049833333333" ixy="0.0" ixz="0.0" iyy="0.001255996129167" iyz="0.0" izz="0.001460916979167"/>
    </inertial>
  </link>

  <link name="base_link"/>

  <joint name="object" type="floating">
    <!-- <origin xyz="0.15075 0.0745 0.5" rpy="0 0 0"/> -->
    <parent link="base_link"/>
    <child  link="object_link"/>
  </joint>
  
</robot>