mujoco

<mujoco>
  <extension>
    <plugin plugin="mujoco.sdf.nut">
      <instance name="nut">
        <config key="radius" value="0.26"/>
      </instance>
    </plugin>
    <plugin plugin="mujoco.sdf.bolt">
      <instance name="bolt">
        <config key="radius" value="0.255"/>
      </instance>
    </plugin>
  </extension>

  <compiler autolimits="true"/>

  <include file="scene.xml"/>

  <visual>
    <map force="0.05"/>
  </visual>

  <asset>
    <mesh name="nut">
      <plugin instance="nut"/>
    </mesh>
    <mesh name="bolt">
      <plugin instance="bolt"/>
    </mesh>
  </asset>

  <option sdf_iterations="10" sdf_initpoints="20"/>

  <default>
    <geom solref="0.01 1" solimp=".95 .99 .0001" friction="0.01"/>
  </default>

  <statistic meansize=".1"/>

  <worldbody>
    <body pos="-0.0012496 0.00329058 0.830362" quat="-0.000212626 0.999996 -0.00200453 0.00185878">
      <joint type="free" damping="30"/>
      <geom type="sdf" name="nut" mesh="nut" rgba="0.83 0.68 0.4 1">
        <plugin instance="nut"/>
      </geom>
    </body>
    <body euler="180 0 0">
      <geom type="sdf" name="bolt" mesh="bolt" rgba="0.7 0.7 0.7 1">
        <plugin instance="bolt"/>
      </geom>
    </body>
    <light name="left" pos="-1 0 2" cutoff="80"/>
    <light name="right" pos="1 0 2" cutoff="80"/>
  </worldbody>
</mujoco>