mujoco

<mujoco model="Collide spherical meshes">
  <statistic extent="1.5" meansize=".05"/>

  <visual>
    <rgba haze="0.15 0.25 0.35 1"/>
    <map shadowscale="0.5" zfar="40"/>
  </visual>

  <asset>
    <mesh name="sphere" builtin="sphere" params="3" scale=".08 .08 .08"/>
    <texture type="skybox" builtin="gradient" rgb1="0.3 0.5 0.7" rgb2="0 0 0" width="64" height="64"/>
    <texture name="texplane" type="2d" builtin="checker" rgb1=".2 .3 .4" rgb2=".1 0.15 0.2" width="512" height="512" mark="cross" markrgb=".8 .8 .8"/>
    <material name="matplane" reflectance="0.3" texture="texplane" texrepeat="1 1" texuniform="true"/>
  </asset>

  <default>
    <geom condim="1" solref="2e-3 1"/>
  </default>

  <option timestep="1e-3" solver="CG" iterations="20"/>

  <worldbody>
    <light directional="true" diffuse=".4 .4 .4" specular="0.1 0.1 0.1" pos="0 0 5" castshadow="false"/>
    <light diffuse=".6 .6 .6" specular="0.2 0.2 0.2" pos="0 0 4"/>

    <geom name="ground" type="plane" size=".5 .5 .01" pos="0 0 0" quat="1 0 0 0" material="matplane" condim="1"/>
    <replicate count="4" euler="0 0 90">
      <geom type="plane" size=".1 .5 .01" zaxis="1 0 0"  pos="-.5 0 .1"/>
    </replicate>

    <replicate count="5" offset=".16 0 0">
      <replicate count="5" offset="0 .16 0">
        <replicate count="4" offset="0 0 .3">
          <body pos="-.3 -.3 .3" euler="10 20 30">
            <freejoint/>
            <geom type="mesh" mesh="sphere"/>
          </body>
        </replicate>
      </replicate>
    </replicate>
  </worldbody>
</mujoco>