mujoco

<mujoco model="touchtest">
  <compiler autolimits="true"/>

  <extension>
    <plugin plugin="mujoco.sensor.touch_grid"/>
  </extension>

  <asset>
    <texture name="grid" type="2d" builtin="checker" rgb1=".1 .2 .3" rgb2=".2 .3 .4" width="300" height="300" mark="edge" markrgb=".2 .3 .4"/>
    <material name="grid" texture="grid" texrepeat="3 1" texuniform="true"/>
    <hfield file="a.png" size="0.2 0.2 0.02 0.015"/>
  </asset>

  <visual>
      <headlight ambient=".7 .7 .7" diffuse=".2 .2 .2" specular="0.1 0.1 0.1"/>
      <map znear="0.01"/>
      <scale contactwidth=".02" contactheight=".5"/>
  </visual>

  <default>
    <geom friction="0.4" solimp="0 0.95 0.02"/>
  </default>

  <statistic center="0 0 1" extent="1" meansize=".1"/>

  <worldbody>
    <light pos="1 0 .3" dir="-1 0 -.3"/>
    <light pos="-1 0 .3" dir="1 0 -.3"/>
    <geom name="floor" pos="0 0 -0.01" type="plane" size="1 1 .01"/>

    <geom name="a" type="hfield" hfield="a" rgba=".5 .5 .7 1"/>

    <body name="ball" pos="0 0 1">
      <joint name="x" type="slide" axis="1 0 0" damping="1"/>
      <joint name="y" type="slide" axis="0 1 0" damping="1"/>
      <joint name="z" type="slide" axis="0 0 1"/>
      <joint name="rx" axis="1 0 0" springdamper="0.2 1"/>
      <joint name="ry" axis="0 1 0" springdamper="0.2 1"/>
      <geom type="ellipsoid" size=".3 .5 .1" mass="0.1" rgba=".5 .5 .5 .3"/>
      <site name="touch" pos="0 0 .1"/>
    </body>
  </worldbody>

  <sensor>
    <plugin name="touch" plugin="mujoco.sensor.touch_grid" objtype="site" objname="touch">
      <config key="size" value="7 7"/>
      <config key="fov" value="45 45"/>
      <config key="gamma" value="0"/>
      <config key="nchannel" value="3"/>
    </plugin>
  </sensor>
</mujoco>