<mujoco model="cube_inner">
    <worldbody>
        <body name="object_0" pos="0.3 0 .02">
            <freejoint name="object_joint_0"/>
            <geom name="object_0" class="cube"/>
            <site name="com_0" group="5"/>
        </body>
        <body name="object_target_0" pos="0.45 0 .02" mocap="true">
            <geom name="target_object_0" class="cube" rgba=".5 .5 .5 .2" contype="0" conaffinity="0"/>
        </body>
    </worldbody>
</mujoco>
