Grasping and tactile sensing with 2F85 and multi-SDF-geom objects

[benudavis]

Intro

Hi!

I am a graduate student at Berkeley, I use MuJoCo for my research on tactile sensing for manipulation.

My setup

MuJoCo 3.3.6, Python, Windows 11

My question

I'm trying to use the built-in tactile sensors on a UR10 mounted 2F-85 gripper (models from menagerie). I'm also hoping to use some realistic objects from Google's scanned object dataset, converted to MJCF files.

The imported object model bodies contain multiple mesh geoms and can be grasped without problems:
https://github.com/user-attachments/assets/0c915496-5639-4d0a-9834-89e7ebdd8d2a

However, the tactile sensor requires SDF-type geoms and doesn't generate signals from the mesh geoms. I can convert the individual geoms in the object model to sdf, but it causes the simulation to stop with the error mujoco.FatalError: Node not found or mujoco.FatalError: mjc_getSDF: Plugin is not a signed distance field at slot 0. This occurs when the gripper comes into contact/close to contact with the object:
https://github.com/user-attachments/assets/e65f3404-9f86-4a33-92b9-1fce37dd1a9d

When I remove the tactile sensor mesh geoms (hand_right_pad_tactile and hand_left_pad_tactile), the simulation slows down but doesn't stop or throw an error:
https://github.com/user-attachments/assets/f164fb95-c7c0-40ee-9526-ec8410f343ef

Maybe, the sdf-mesh collisions between the tactile sensors and SDFs of the object are too much to handle. If I instead grasp a simpler SDF object using the mujoco.sdf.bowl plugin, the simulation runs (slowly) with the tactile sensors:
https://github.com/user-attachments/assets/cb1a216d-bd16-47be-afe9-142162ef15fc

Is there a good solution to this issue? I'm thinking I could create lower fidelity objects composed of primitive geoms or few SDFs, but it would be nice to somehow use the existing MJCF dataset. Thanks!

Minimal model and/or code that explain my question

This folder contains the MJCF files and associated assets. I can encounter the issue by loading scene.xml into the Mujoco interactive viewer.
sdf test.zip

Robot Model:

minimal XML

<mujoco model="ur10e">
  <compiler angle="radian" meshdir="assets/"/>
  <size nkey="1"/>

  <default>
    <default class="ur10e">
      <material shininess="0.25"/>
      <joint range="-6.28319 6.28319" armature="0.1"/>
      <site size="0.001 0.005 0.005" group="4" rgba="0.5 0.5 0.5 0.3"/>
      <general ctrlrange="-6.2831 6.2831" biastype="affine" gainprm="5000" biasprm="0 -5000 -500"/>
      <default class="size4">
        <joint damping="10"/>
        <general forcerange="-330 330"/>
      </default>
      <default class="size3">
        <joint damping="5"/>
        <general forcerange="-150 150"/>
        <default class="size3_limited">
          <joint range="-3.1415 3.1415"/>
          <general ctrlrange="-3.1415 3.1415"/>
        </default>
      </default>
      <default class="size2">
        <joint damping="2"/>
        <general forcerange="-56 56"/>
      </default>
      <default class="visual">
        <geom type="mesh" contype="0" conaffinity="0" group="2"/>
      </default>
      <default class="collision">
        <geom type="capsule" group="3"/>
        <default class="eef_collision">
          <geom type="cylinder"/>
        </default>
      </default>
    </default>
    <default class="hand_main">
      <default class="hand_2f85">
        <mesh scale="0.001 0.001 0.001"/>
        <general biastype="affine"/>
        <default class="hand_driver">
          <joint solreflimit="0.005" solimplimit="0.95 0.99" range="0 0.8" armature="0.005" damping="0.1"/>
        </default>
        <default class="hand_follower">
          <joint solreflimit="0.005" solimplimit="0.95 0.99" range="-0.872664 0.872664" armature="0.001"/>
        </default>
        <default class="hand_spring_link">
          <joint springref="2.62" stiffness="0.05" range="-0.296706 0.8" armature="0.001" damping="0.00125"/>
        </default>
        <default class="hand_coupler">
          <joint solreflimit="0.005" solimplimit="0.95 0.99" range="-1.57 0" armature="0.001"/>
        </default>
        <default class="hand_visual">
          <geom type="mesh" contype="0" conaffinity="0" group="2"/>
        </default>
        <default class="hand_collision">
          <geom type="mesh" group="3"/>
          <default class="hand_pad_box1">
            <geom size="0.011 0.004 0.009375" type="box" priority="1" friction="0.7" solref="0.004" solimp="0.95 0.99" rgba="0.55 0.55 0.55 1"/>
          </default>
          <default class="hand_pad_box2">
            <geom size="0.011 0.004 0.009375" type="box" priority="1" friction="0.6" solref="0.004" solimp="0.95 0.99" rgba="0.45 0.45 0.45 1"/>
          </default>

          <default class="hand_pad_box_tactile">
            <geom size="0.011 0.004 0.01875" type="mesh" mesh="tactile_pad" mass="0" contype="0" conaffinity="0"/>
          </default>

        </default>
      </default>
    </default>
  </default>

  <asset>
    <material name="black" class="ur10e" rgba="0.033 0.033 0.033 1"/>
    <material name="jointgray" class="ur10e" rgba="0.278 0.278 0.278 1"/>
    <material name="linkgray" class="ur10e" rgba="0.82 0.82 0.82 1"/>
    <material name="urblue" class="ur10e" rgba="0.49 0.678 0.8 1"/>
    <material name="hand_metal" rgba="0.58 0.58 0.58 1"/>
    <material name="hand_silicone" rgba="0.1882 0.1882 0.1882 1"/>
    <material name="hand_gray" rgba="0.4627 0.4627 0.4627 1"/>
    <material name="hand_black" rgba="0.149 0.149 0.149 1"/>
    <mesh name="base_0" content_type="model/obj" file="base_0.obj"/>
    <mesh name="base_1" content_type="model/obj" file="base_1.obj"/>
    <mesh name="shoulder_0" content_type="model/obj" file="shoulder_0.obj"/>
    <mesh name="shoulder_1" content_type="model/obj" file="shoulder_1.obj"/>
    <mesh name="shoulder_2" content_type="model/obj" file="shoulder_2.obj"/>
    <mesh name="upperarm_0" content_type="model/obj" file="upperarm_0.obj"/>
    <mesh name="upperarm_1" content_type="model/obj" file="upperarm_1.obj"/>
    <mesh name="upperarm_2" content_type="model/obj" file="upperarm_2.obj"/>
    <mesh name="upperarm_3" content_type="model/obj" file="upperarm_3.obj"/>
    <mesh name="forearm_0" content_type="model/obj" file="forearm_0.obj"/>
    <mesh name="forearm_1" content_type="model/obj" file="forearm_1.obj"/>
    <mesh name="forearm_2" content_type="model/obj" file="forearm_2.obj"/>
    <mesh name="forearm_3" content_type="model/obj" file="forearm_3.obj"/>
    <mesh name="wrist1_0" content_type="model/obj" file="wrist1_0.obj"/>
    <mesh name="wrist1_1" content_type="model/obj" file="wrist1_1.obj"/>
    <mesh name="wrist1_2" content_type="model/obj" file="wrist1_2.obj"/>
    <mesh name="wrist2_0" content_type="model/obj" file="wrist2_0.obj"/>
    <mesh name="wrist2_1" content_type="model/obj" file="wrist2_1.obj"/>
    <mesh name="wrist2_2" content_type="model/obj" file="wrist2_2.obj"/>
    <mesh name="wrist3" content_type="model/obj" file="wrist3.obj"/>
    <mesh name="hand_base_mount" class="hand_2f85" content_type="model/stl" file="base_mount.stl"/>
    <mesh name="hand_base" class="hand_2f85" content_type="model/stl" file="base.stl"/>
    <mesh name="hand_driver" class="hand_2f85" content_type="model/stl" file="driver.stl"/>
    <mesh name="hand_coupler" class="hand_2f85" content_type="model/stl" file="coupler.stl"/>
    <mesh name="hand_follower" class="hand_2f85" content_type="model/stl" file="follower.stl"/>
    <mesh name="hand_pad" class="hand_2f85" content_type="model/stl" file="pad.stl"/>
    <mesh name="hand_silicone_pad" class="hand_2f85" content_type="model/stl" file="silicone_pad.stl"/>
    <mesh name="hand_spring_link" class="hand_2f85" content_type="model/stl" file="spring_link.stl"/>
    <mesh name="tactile_pad" builtin="plate" params="11 19" scale="0.011 0.004 0.01875" refquat="0.707 0.707 0 0"/>
    <mesh name="tactile_pad_hires" builtin="plate" params="44 75" scale="0.011 0.004 0.01875" refquat="0.707 0.707 0 0"/>
  </asset>

  <worldbody>
    <light name="spotlight" target="wrist_2_link" pos="0 -1 2" dir="0 0 -1" mode="targetbodycom"/>
    <camera name="worldcam" pos="0 -1.6 0.7" euler="45 0 0" mode="fixed" fovy="50"/>
    <body name="base" childclass="ur10e" quat="0 0 0 -1" pos="0 0.7 0">
      <inertial pos="0 0 0" mass="4" diaginertia="0.00610633 0.00610633 0.01125"/>
      <geom class="visual" material="black" mesh="base_0"/>
      <geom class="visual" material="jointgray" mesh="base_1"/>
      <body name="shoulder_link" pos="0 0 0.181">
        <inertial pos="0 0 0" mass="7.778" diaginertia="0.0314743 0.0314743 0.0218756"/>
        <joint name="shoulder_pan_joint" class="size4" pos="0 0 0" axis="0 0 1"/>
        <geom class="visual" material="urblue" mesh="shoulder_0"/>
        <geom class="visual" material="black" mesh="shoulder_1"/>
        <geom class="visual" material="jointgray" mesh="shoulder_2"/>
        <geom class="collision" size="0.078 0.08" pos="0 0 -0.05"/>
        <body name="upper_arm_link" pos="0 0.176 0" quat="0.707107 0 0.707107 0">
          <inertial pos="0 0 0.3065" mass="12.93" diaginertia="0.423074 0.423074 0.0363656"/>
          <joint name="shoulder_lift_joint" class="size4" pos="0 0 0" axis="0 1 0"/>
          <geom class="visual" material="black" mesh="upperarm_0"/>
          <geom class="visual" material="jointgray" mesh="upperarm_1"/>
          <geom class="visual" material="urblue" mesh="upperarm_2"/>
          <geom class="visual" material="linkgray" mesh="upperarm_3"/>
          <geom class="collision" size="0.078 0.08" pos="0 -0.05 0" quat="0.707107 0.707107 0 0"/>
          <geom class="collision" size="0.06 0.3" pos="0 0 0.3"/>
          <body name="forearm_link" pos="0 -0.137 0.613">
            <inertial pos="0 0 0.2855" mass="3.87" diaginertia="0.11059 0.11059 0.0108844"/>
            <joint name="elbow_joint" class="size3_limited" pos="0 0 0" axis="0 1 0"/>
            <geom class="visual" material="urblue" mesh="forearm_0"/>
            <geom class="visual" material="black" mesh="forearm_1"/>
            <geom class="visual" material="jointgray" mesh="forearm_2"/>
            <geom class="visual" material="linkgray" mesh="forearm_3"/>
            <geom class="collision" size="0.058 0.065" pos="0 0.08 0" quat="0.707107 0.707107 0 0"/>
            <geom class="collision" size="0.043 0.28" pos="0 0 0.29"/>
            <body name="wrist_1_link" pos="0 0 0.571" quat="0.707107 0 0.707107 0">
              <inertial pos="0 0.135 0" quat="0.5 0.5 -0.5 0.5" mass="1.96" diaginertia="0.0055125 0.00510825 0.00510825"/>
              <joint name="wrist_1_joint" class="size2" pos="0 0 0" axis="0 1 0"/>
              <geom class="visual" material="black" mesh="wrist1_0"/>
              <geom class="visual" material="urblue" mesh="wrist1_1"/>
              <geom class="visual" material="jointgray" mesh="wrist1_2"/>
              <geom class="collision" size="0.05 0.07" pos="0 0.06 0" quat="0.707107 0.707107 0 0"/>
              <body name="wrist_2_link" pos="0 0.135 0">
                <inertial pos="0 0 0.12" quat="0.5 0.5 -0.5 0.5" mass="1.96" diaginertia="0.0055125 0.00510825 0.00510825"/>
                <joint name="wrist_2_joint" class="size2" pos="0 0 0" axis="0 0 1"/>
                <geom class="visual" material="black" mesh="wrist2_0"/>
                <geom class="visual" material="urblue" mesh="wrist2_1"/>
                <geom class="visual" material="jointgray" mesh="wrist2_2"/>
                <geom class="collision" size="0.046 0.065" pos="0 0 0.05"/>
                <geom class="collision" size="0.046 0.043" pos="0 0.028 0.12" quat="0.707107 0.707107 0 0"/>
                <body name="wrist_3_link" pos="0 0 0.12">
                  <inertial pos="0 0.092 0" quat="0 0.707107 -0.707107 0" mass="0.202" diaginertia="0.000204525 0.000144346 0.000144346"/>
                  <joint name="wrist_3_joint" class="size2" pos="0 0 0" axis="0 1 0"/>
                  <geom class="visual" material="linkgray" mesh="wrist3"/>
                  <geom class="eef_collision" size="0.046 0.02" pos="0 0.097 0" quat="0.707107 0.707107 0 0"/>
                  <site name="attachment_site" pos="0 0.1 0" quat="-0.707107 0.707107 0 0"/>
                  <body name="hand_world" pos="0 0.1 0" quat="-0.707107 0.707107 0 0">
                    <body name="hand_base_mount" childclass="hand_2f85" pos="0 0 0.007">
                      <geom class="hand_visual" material="hand_black" mesh="hand_base_mount"/>
                      <geom class="hand_collision" mesh="hand_base_mount"/>
                      <body name="hand_base" pos="0 0 0.0038" quat="0.707107 0 0 -0.707107">
                        <inertial pos="0 -2.70394e-05 0.0354675" quat="0.999999 -0.00152849 0 0" mass="0.777441" diaginertia="0.000260285 0.000225381 0.000152708"/>
                        <geom class="hand_visual" material="hand_black" mesh="hand_base"/>
                        <geom class="hand_collision" mesh="hand_base"/>
                        <site name="hand_pinch" pos="0 0 0.145" group="5" rgba="0.9 0.9 0.9 1"/>
                        <body name="hand_right_driver" pos="0 0.0306011 0.054904">
                          <inertial pos="2.96931e-12 0.0177547 0.00107314" quat="0.681301 0.732003 0 0" mass="0.00899563" diaginertia="1.72352e-06 1.60906e-06 3.22006e-07"/>
                          <joint name="hand_right_driver_joint" class="hand_driver" pos="0 0 0" axis="1 0 0"/>
                          <geom class="hand_visual" material="hand_gray" mesh="hand_driver"/>
                          <geom class="hand_collision" mesh="hand_driver"/>
                          <body name="hand_right_coupler" pos="0 0.0315 -0.0041">
                            <inertial pos="0 0.00301209 0.0232175" quat="0.705636 -0.0455904 0.0455904 0.705636" mass="0.0140974" diaginertia="4.16206e-06 3.52216e-06 8.88131e-07"/>
                            <joint name="hand_right_coupler_joint" class="hand_coupler" pos="0 0 0" axis="1 0 0"/>
                            <geom class="hand_visual" material="hand_black" mesh="hand_coupler"/>
                            <geom class="hand_collision" mesh="hand_coupler"/>
                          </body>
                        </body>
                        <body name="hand_right_spring_link" pos="0 0.0132 0.0609">
                          <inertial pos="-8.65005e-09 0.0181624 0.0212658" quat="0.663403 -0.244737 0.244737 0.663403" mass="0.0221642" diaginertia="8.96853e-06 6.71733e-06 2.63931e-06"/>
                          <joint name="hand_right_spring_link_joint" class="hand_spring_link" pos="0 0 0" axis="1 0 0" springref="2.62" stiffness="0.4"/>
                          <geom class="hand_visual" material="hand_black" mesh="hand_spring_link"/>
                          <geom class="hand_collision" mesh="hand_spring_link"/>
                          <body name="hand_right_follower" pos="0 0.055 0.0375">
                            <inertial pos="0 -0.011046 0.0124786" quat="0.986437 0.164143 0 0" mass="0.0125222" diaginertia="2.67415e-06 2.4559e-06 6.02031e-07"/>
                            <joint name="hand_right_follower_joint" class="hand_follower" pos="0 -0.018 0.0065" axis="1 0 0"/>
                            <geom class="hand_visual" material="hand_black" mesh="hand_follower"/>
                            <geom class="hand_collision" mesh="hand_follower"/>
                            <body name="hand_right_pad" pos="0 -0.0189 0.01352">
                              <inertial pos="0 -0.0025 0.0185" quat="0.707107 0 0 0.707107" mass="0.0035" diaginertia="4.73958e-07 3.64583e-07 1.23958e-07"/>
                              <geom name="hand_right_pad1" class="hand_pad_box1" pos="0 -0.0026 0.028125" mass="0"/>
                              <geom name="hand_right_pad2" class="hand_pad_box2" pos="0 -0.0026 0.009375" mass="0"/>
                              <geom name="hand_right_pad_tactile" class="hand_pad_box_tactile" pos="0 -0.0026 0.01875" rgba="1 1 0 0.3"/>
                              <geom class="hand_visual" mesh="hand_pad"/>
                              <body name="hand_right_silicone_pad">
                                <geom class="hand_visual" material="hand_black" mesh="hand_silicone_pad"/>
                              </body>
                            </body>
                          </body>
                        </body>
                        <body name="hand_left_driver" pos="0 -0.0306011 0.054904" quat="0 0 0 1">
                          <inertial pos="0 0.0177547 0.00107314" quat="0.681301 0.732003 0 0" mass="0.00899563" diaginertia="1.72352e-06 1.60906e-06 3.22006e-07"/>
                          <joint name="hand_left_driver_joint" class="hand_driver" pos="0 0 0" axis="1 0 0"/>
                          <geom class="hand_visual" material="hand_gray" mesh="hand_driver"/>
                          <geom class="hand_collision" mesh="hand_driver"/>
                          <body name="hand_left_coupler" pos="0 0.0315 -0.0041">
                            <inertial pos="0 0.00301209 0.0232175" quat="0.705636 -0.0455904 0.0455904 0.705636" mass="0.0140974" diaginertia="4.16206e-06 3.52216e-06 8.88131e-07"/>
                            <joint name="hand_left_coupler_joint" class="hand_coupler" pos="0 0 0" axis="1 0 0"/>
                            <geom class="hand_visual" material="hand_black" mesh="hand_coupler"/>
                            <geom class="hand_collision" mesh="hand_coupler"/>
                          </body>
                        </body>
                        <body name="hand_left_spring_link" pos="0 -0.0132 0.0609" quat="0 0 0 1">
                          <inertial pos="-8.65005e-09 0.0181624 0.0212658" quat="0.663403 -0.244737 0.244737 0.663403" mass="0.0221642" diaginertia="8.96853e-06 6.71733e-06 2.63931e-06"/>
                          <joint name="hand_left_spring_link_joint" class="hand_spring_link" pos="0 0 0" axis="1 0 0" springref="2.62" stiffness="0.4"/>
                          <geom class="hand_visual" material="hand_black" mesh="hand_spring_link"/>
                          <geom class="hand_collision" mesh="hand_spring_link"/>
                          <body name="hand_left_follower" pos="0 0.055 0.0375">
                            <inertial pos="0 -0.011046 0.0124786" quat="0.986437 0.164143 0 0" mass="0.0125222" diaginertia="2.67415e-06 2.4559e-06 6.02031e-07"/>
                            <joint name="hand_left_follower_joint" class="hand_follower" pos="0 -0.018 0.0065" axis="1 0 0"/>
                            <geom class="hand_visual" material="hand_black" mesh="hand_follower"/>
                            <geom class="hand_collision" mesh="hand_follower"/>
                            <body name="hand_left_pad" pos="0 -0.0189 0.01352">
                              <inertial pos="0 -0.0025 0.0185" quat="0.707107 0 0 0.707107" mass="0.0035" diaginertia="4.73958e-07 3.64583e-07 1.23958e-07"/>
                              <geom name="hand_left_pad1" class="hand_pad_box1" pos="0 -0.0026 0.028125" mass="0" rgba="0 1 0 0.3"/>
                              <geom name="hand_left_pad2" class="hand_pad_box2" pos="0 -0.0026 0.009375" mass="0" rgba="0 0 1 0.3"/>
                              <geom name="hand_left_pad_tactile" class="hand_pad_box_tactile" pos="0 -0.0026 0.01875" rgba="1 1 0 0.3"/>
                              <geom class="hand_visual" mesh="hand_pad"/>
                              <body name="hand_left_silicone_pad">
                                <geom class="hand_visual" material="hand_black" mesh="hand_silicone_pad"/>
                              </body>
                            </body>
                          </body>
                        </body>
                      </body>
                    </body>
                  </body>
                </body>
              </body>
            </body>
          </body>
        </body>
      </body>
    </body>
  </worldbody>

  <contact>
    <exclude body1="hand_base" body2="hand_right_driver"/>
    <exclude body1="hand_base" body2="hand_right_spring_link"/>
    <exclude body1="hand_base" body2="hand_left_driver"/>
    <exclude body1="hand_base" body2="hand_left_spring_link"/>
    <exclude body1="hand_right_coupler" body2="hand_right_follower"/>
    <exclude body1="hand_left_coupler" body2="hand_left_follower"/>
  </contact>

  <equality>
    <connect body1="hand_right_follower" body2="hand_right_coupler" anchor="0 0 0" solref="0.005" solimp="0.95 0.99"/>
    <connect body1="hand_left_follower" body2="hand_left_coupler" anchor="0 0 0" solref="0.005" solimp="0.95 0.99"/>
    <joint joint1="hand_right_driver_joint" joint2="hand_left_driver_joint" polycoef="0 1 0 0 0" solref="0.005" solimp="0.95 0.99"/>
  </equality>

  <tendon>
    <fixed name="hand_split">
      <joint joint="hand_right_driver_joint" coef="0.5"/>
      <joint joint="hand_left_driver_joint" coef="0.5"/>
    </fixed>
  </tendon>

  <actuator>
    <general name="shoulder_pan" class="size4" joint="shoulder_pan_joint" gainprm="25000" biasprm="0 -25000 -2500"/>
    <general name="shoulder_lift" class="size4" joint="shoulder_lift_joint" gainprm="25000" biasprm="0 -25000 -2500"/>
    <general name="elbow" class="size3_limited" joint="elbow_joint" gainprm="25000" biasprm="0 -25000 -2500"/>
    <general name="wrist_1" class="size2" joint="wrist_1_joint" gainprm="25000" biasprm="0 -25000 -2500"/>
    <general name="wrist_2" class="size2" joint="wrist_2_joint" gainprm="25000" biasprm="0 -25000 -2500"/>
    <general name="wrist_3" class="size2" joint="wrist_3_joint" gainprm="25000" biasprm="0 -25000 -2500"/>
    <general name="hand_fingers_actuator" class="hand_2f85" tendon="hand_split" ctrlrange="0 255" forcerange="-5 5" gainprm="0.313725" biasprm="0 -100 -10"/>
  </actuator>

  <!-- tactile sensors -->
  <sensor>
    <tactile name="left_pad_tactile" geom="hand_left_pad_tactile" mesh="tactile_pad"/>
    <tactile name="right_pad_tactile" geom="hand_right_pad_tactile" mesh="tactile_pad"/>
  </sensor>
</mujoco>

Scene:

minimal XML

<mujoco>
  <include file="ur10e_2f85_tactile.xml"/>
  <include file="model.xml"/>

  <option integrator="implicitfast"/>
  <option viscosity="0.0001"/>
  <option noslip_iterations="2">
    <flag multiccd="enable"/>
  </option>
  <option cone="elliptic"/>
  <option sdf_iterations="5" sdf_initpoints="20"/>
  <option timestep="1e-4"/>

  <extension>
    <plugin plugin="mujoco.sdf.bowl">
      <instance name="bowl">
        <config key="radius" value="0.025"/>
        <config key="height" value=".002"/>
        <config key="thickness" value=".004"/>
      </instance>
    </plugin>
  </extension>

  <default>
    <geom friction="0.6"/>
  </default>

  <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="2 2" texuniform="true"
    reflectance=".2"/>
    <mesh name="bowl">
      <plugin instance="bowl"/>
    </mesh>
  </asset>

  <visual>
    <headlight diffuse="0.6 0.6 0.6" ambient="0.6 0.6 0.6" specular="0 0 0"/>
    <rgba haze="0.15 0.25 0.35 1"/>
    <global azimuth="60" elevation="-20"/>
  </visual>

  <worldbody>
    <geom name="ground" type="plane" pos="0 0 0" size="0 0 .1" material="grid" friction="0.2"/>
    <body name="obj" pos="0 0 0.06">
      <geom type="sdf" name="object" mesh="bowl" rgba=".2 .8 .8 1">
        <plugin instance="bowl"/>
      </geom>
      <freejoint/>
    </body>
  </worldbody>

  <keyframe>
    <key 
      name="0" 
      qpos="1.31960209 -1.19911559  2.14216286 -2.51386286 -1.57079603 -0.25119419 0 0 0 0 0 0 0 0 -0.32 0.09 0.02"
      ctrl="1.31960209 -1.19911559  2.14216286 -2.51386286 -1.57079603 -0.25119419"
    />
    <key 
      name="1" 
      qpos="0.81960209 -1.25911559  2.14216286 -2.41386286 -1.57079603 -0.25119419 0 0 0 0 0 0 0 0 -0.32 0.09 0.02"
      ctrl="0.81960209 -1.25911559  2.14216286 -2.41386286 -1.57079603 -0.25119419"
    />
  </keyframe>
</mujoco>

Object Model:

minimal XML

<mujoco model="model">
  <asset>
    <texture type="2d" name="texture" file="texture.png"/>
    <material name="material_0" texture="texture" specular="0.22449833333333333" shininess="0.000224041"/>
    <mesh name="model" file="model.obj"/>
    <mesh name="model_collision_0" file="model_collision_0.obj"/>
    <mesh name="model_collision_1" file="model_collision_1.obj"/>
    <mesh name="model_collision_2" file="model_collision_2.obj"/>
    <mesh name="model_collision_3" file="model_collision_3.obj"/>
    <mesh name="model_collision_4" file="model_collision_4.obj"/>
    <mesh name="model_collision_5" file="model_collision_5.obj"/>
    <mesh name="model_collision_6" file="model_collision_6.obj"/>
    <mesh name="model_collision_7" file="model_collision_7.obj"/>
    <mesh name="model_collision_8" file="model_collision_8.obj"/>
    <mesh name="model_collision_9" file="model_collision_9.obj"/>
    <mesh name="model_collision_10" file="model_collision_10.obj"/>
    <mesh name="model_collision_11" file="model_collision_11.obj"/>
    <mesh name="model_collision_12" file="model_collision_12.obj"/>
    <mesh name="model_collision_13" file="model_collision_13.obj"/>
    <mesh name="model_collision_14" file="model_collision_14.obj"/>
    <mesh name="model_collision_15" file="model_collision_15.obj"/>
    <mesh name="model_collision_16" file="model_collision_16.obj"/>
    <mesh name="model_collision_17" file="model_collision_17.obj"/>
    <mesh name="model_collision_18" file="model_collision_18.obj"/>
    <mesh name="model_collision_19" file="model_collision_19.obj"/>
    <mesh name="model_collision_20" file="model_collision_20.obj"/>
    <mesh name="model_collision_21" file="model_collision_21.obj"/>
    <mesh name="model_collision_22" file="model_collision_22.obj"/>
    <mesh name="model_collision_23" file="model_collision_23.obj"/>
    <mesh name="model_collision_24" file="model_collision_24.obj"/>
    <mesh name="model_collision_25" file="model_collision_25.obj"/>
    <mesh name="model_collision_26" file="model_collision_26.obj"/>
    <mesh name="model_collision_27" file="model_collision_27.obj"/>
    <mesh name="model_collision_28" file="model_collision_28.obj"/>
    <mesh name="model_collision_29" file="model_collision_29.obj"/>
    <mesh name="model_collision_30" file="model_collision_30.obj"/>
    <mesh name="model_collision_31" file="model_collision_31.obj"/>
  </asset>
  <worldbody>
    <body name="model" pos="-0.3 0.18 0.05">
      <geom material="material_0" mesh="model" type="mesh" contype="0" conaffinity="0" group="2"/>
      <geom mesh="model_collision_0" type="sdf" group="3"/>
      <geom mesh="model_collision_1" type="sdf" group="3"/>
      <geom mesh="model_collision_2" type="sdf" group="3"/>
      <geom mesh="model_collision_3" type="sdf" group="3"/>
      <geom mesh="model_collision_4" type="sdf" group="3"/>
      <geom mesh="model_collision_5" type="sdf" group="3"/>
      <geom mesh="model_collision_6" type="sdf" group="3"/>
      <geom mesh="model_collision_7" type="sdf" group="3"/>
      <geom mesh="model_collision_8" type="sdf" group="3"/>
      <geom mesh="model_collision_9" type="sdf" group="3"/>
      <geom mesh="model_collision_10" type="sdf" group="3"/>
      <geom mesh="model_collision_11" type="sdf" group="3"/>
      <geom mesh="model_collision_12" type="sdf" group="3"/>
      <geom mesh="model_collision_13" type="sdf" group="3"/>
      <geom mesh="model_collision_14" type="sdf" group="3"/>
      <geom mesh="model_collision_15" type="sdf" group="3"/>
      <geom mesh="model_collision_16" type="sdf" group="3"/>
      <geom mesh="model_collision_17" type="sdf" group="3"/>
      <geom mesh="model_collision_18" type="sdf" group="3"/>
      <geom mesh="model_collision_19" type="sdf" group="3"/>
      <geom mesh="model_collision_20" type="sdf" group="3"/>
      <geom mesh="model_collision_21" type="sdf" group="3"/>
      <geom mesh="model_collision_22" type="sdf" group="3"/>
      <geom mesh="model_collision_23" type="sdf" group="3"/>
      <geom mesh="model_collision_24" type="sdf" group="3"/>
      <geom mesh="model_collision_25" type="sdf" group="3"/>
      <geom mesh="model_collision_26" type="sdf" group="3"/>
      <geom mesh="model_collision_27" type="sdf" group="3"/>
      <geom mesh="model_collision_28" type="sdf" group="3"/>
      <geom mesh="model_collision_29" type="sdf" group="3"/>
      <geom mesh="model_collision_30" type="sdf" group="3"/>
      <geom mesh="model_collision_31" type="sdf" group="3"/>
      <freejoint/>
    </body>
  </worldbody>
</mujoco>

Confirmations

• I searched the latest documentation thoroughly before posting.
• I searched previous Issues and Discussions, I am certain this has not been raised before.

[quagla]

Hi thanks for trying the sensor!

So it actually looks like you are trying to use SDF collisions, is this intentional? If you want standard convex collisions plus the tactile information, there is an easier way: mark the meshes for which you want tactile information for with mesh.needsdf = True (this has to be done in python on the mjSpec). Sorry, this is a hidden feature and not in the docs because not part of the XML! Maybe it should be..