URDF → MJCF conversion for complex models

[AntonioViscomi]

Intro

Hi!

I am a robotics engineer working on simulations of the iCub humanoid robot using MuJoCo. Specifically, I am trying to transition from a well-validated URDF model to an MJCF model.

My setup

• MuJoCo version 3.4.0
• x86-64
• Windows, 11

My question

I tried several URDF-to-MJCF converters, but none of them successfully handled this conversion.

Our model is large and complex (many rigid bodies, frames, meshes, etc.), which makes the converter output difficult to navigate and compare against the original model to diagnose what went wrong.

I therefore decided to write a custom conversion script based on dm_control that replicates the URDF structure as closely as possible, aiming for a near one-to-one mapping. As a result, the output MJCF retains the URDF convention of having two meshes per body:

• one for visualization (with conaffinity/contype set to 0);
• one for collision (with custom conaffinity/contype values).

I am aware this approach deviates from idiomatic MJCF conventions, however, I am still early in my MuJoCo journey and my priority was correctness first. The visual-only meshes can later be removed either manually or programmatically, relying solely on the collision meshes for both purposes.

So, my questions are the following:

1. Does keeping separate visualization and collision meshes per body introduce meaningful overhead in simulation performance?

2. What is the recommended, reliable, and sustainable way to programmatically convert URDF models to MJCF, especially for large models (e.g. humanoids)?

---

As a starting point, the attached XML was obtained via the compile prebuilt binary. Two known issues arise immediately:

• All actuators and sensors are stripped from the output (which seems expected, since the sensors rely on custom plugins).
• The model spins uncontrollably when loaded into the MuJoCo viewer, even after setting high joint damping values (e.g., damping="10"). I believe this is caused by inter-mesh collisions (i.e., adjacent or overlapping collision meshes) generating large contact forces at initialization. This makes me think that a correct URDF → MJCF conversion pipeline should also include an explicit collision integrity check step (e.g., verifying no meshes overlap in the default pose). Is this assumption correct, and if so, what tooling or methodology do you recommend for this?

To reproduce my issue, the required meshes can be found at: robotology/icub-models @ 0772c7

Minimal model and/or code that explain my question

Model:

minimal XML

<mujoco model="iCub">
  <compiler angle="radian" meshdir="simmechanics/" strippath="false" fusestatic="false"/>

  <asset>
    <mesh name="sim_sea_2-5_root_link" file="sim_sea_2-5_root_link.stl" scale="0.001 0.001 0.001"/>
    <mesh name="sim_ibbbbeba_torso_1" file="sim_ibbbbeba_torso_1.stl" scale="0.001 0.001 0.001"/>
    <mesh name="sim_sea_2-5_l_hip_1" file="sim_sea_2-5_l_hip_1.stl" scale="0.001 0.001 0.001"/>
    <mesh name="sim_sea_2-5_r_hip_1" file="sim_sea_2-5_r_hip_1.stl" scale="0.001 0.001 0.001"/>
    <mesh name="sim_sea_2-5_r_hip_2" file="sim_sea_2-5_r_hip_2.stl" scale="0.001 0.001 0.001"/>
    <mesh name="sim_sea_2-5_r_upper_thigh" file="sim_sea_2-5_r_upper_thigh.stl" scale="0.001 0.001 0.001"/>
    <mesh name="sim_sea_2-5_r_thigh" file="sim_sea_2-5_r_thigh.stl" scale="0.001 0.001 0.001"/>
    <mesh name="sim_sea_2-5_r_shank" file="sim_sea_2-5_r_shank.stl" scale="0.001 0.001 0.001"/>
    <mesh name="sim_sea_2-5_r_ankle" file="sim_sea_2-5_r_ankle.stl" scale="0.001 0.001 0.001"/>
    <mesh name="sim_sea_2-5_r_foot" file="sim_sea_2-5_r_foot.stl" scale="0.001 0.001 0.001"/>
    <mesh name="sim_sea_2-5_l_hip_2" file="sim_sea_2-5_l_hip_2.stl" scale="0.001 0.001 0.001"/>
    <mesh name="sim_sea_2-5_l_upper_thigh" file="sim_sea_2-5_l_upper_thigh.stl" scale="0.001 0.001 0.001"/>
    <mesh name="sim_sea_2-5_l_thigh" file="sim_sea_2-5_l_thigh.stl" scale="0.001 0.001 0.001"/>
    <mesh name="sim_sea_2-5_l_shank" file="sim_sea_2-5_l_shank.stl" scale="0.001 0.001 0.001"/>
    <mesh name="sim_sea_2-5_l_ankle" file="sim_sea_2-5_l_ankle.stl" scale="0.001 0.001 0.001"/>
    <mesh name="sim_sea_2-5_l_foot" file="sim_sea_2-5_l_foot.stl" scale="0.001 0.001 0.001"/>
    <mesh name="sim_ibbbbeba_torso_2" file="sim_ibbbbeba_torso_2.stl" scale="0.001 0.001 0.001"/>
    <mesh name="sim_ibbbbeba_chest" file="sim_ibbbbeba_chest.stl" scale="0.001 0.001 0.001"/>
    <mesh name="sim_ibbbbeba_neck_1" file="sim_ibbbbeba_neck_1.stl" scale="0.001 0.001 0.001"/>
    <mesh name="sim_sea_2-5_l_shoulder_1" file="sim_sea_2-5_l_shoulder_1.stl" scale="0.001 0.001 0.001"/>
    <mesh name="sim_sea_2-5_r_shoulder_1" file="sim_sea_2-5_r_shoulder_1.stl" scale="0.001 0.001 0.001"/>
    <mesh name="sim_sea_2-5_r_shoulder_2" file="sim_sea_2-5_r_shoulder_2.stl" scale="0.001 0.001 0.001"/>
    <mesh name="sim_sea_2-5_r_upper_arm" file="sim_sea_2-5_r_upper_arm.stl" scale="0.001 0.001 0.001"/>
    <mesh name="sim_sea_2-5_r_elbow" file="sim_sea_2-5_r_elbow.stl" scale="0.001 0.001 0.001"/>
    <mesh name="sim_sea_2-5_r_elbow_prosup" file="sim_sea_2-5_r_elbow_prosup.stl" scale="0.001 0.001 0.001"/>
    <mesh name="sim_sea_2-5_r_forearm" file="sim_sea_2-5_r_forearm.stl" scale="0.001 0.001 0.001"/>
    <mesh name="sim_sea_2-5_r_wrist_pitch" file="sim_sea_2-5_r_wrist_pitch.stl" scale="0.001 0.001 0.001"/>
    <mesh name="sim_sea_2-5_r_hand" file="sim_sea_2-5_r_hand.stl" scale="0.001 0.001 0.001"/>
    <mesh name="sim_sea_2-5_l_shoulder_2" file="sim_sea_2-5_l_shoulder_2.stl" scale="0.001 0.001 0.001"/>
    <mesh name="sim_sea_2-5_l_upper_arm" file="sim_sea_2-5_l_upper_arm.stl" scale="0.001 0.001 0.001"/>
    <mesh name="sim_sea_2-5_l_elbow" file="sim_sea_2-5_l_elbow.stl" scale="0.001 0.001 0.001"/>
    <mesh name="sim_sea_2-5_l_elbow_prosup" file="sim_sea_2-5_l_elbow_prosup.stl" scale="0.001 0.001 0.001"/>
    <mesh name="sim_sea_2-5_l_forearm" file="sim_sea_2-5_l_forearm.stl" scale="0.001 0.001 0.001"/>
    <mesh name="sim_sea_2-5_l_wrist_pitch" file="sim_sea_2-5_l_wrist_pitch.stl" scale="0.001 0.001 0.001"/>
    <mesh name="sim_sea_2-5_l_hand" file="sim_sea_2-5_l_hand.stl" scale="0.001 0.001 0.001"/>
    <mesh name="sim_ibbbbeba_neck_2" file="sim_ibbbbeba_neck_2.stl" scale="0.001 0.001 0.001"/>
    <mesh name="sim_ibbbbeba_neck_3" file="sim_ibbbbeba_neck_3.stl" scale="0.001 0.001 0.001"/>
    <mesh name="sim_ibbbbeba_head" file="sim_ibbbbeba_head.stl" scale="0.001 0.001 0.001"/>
    <mesh name="sim_ibbbbeba_eyes_1" file="sim_ibbbbeba_eyes_1.stl" scale="0.001 0.001 0.001"/>
    <mesh name="sim_ibbbbeba_l_eye_2" file="sim_ibbbbeba_l_eye_2.stl" scale="0.001 0.001 0.001"/>
    <mesh name="sim_ibbbbeba_r_eye_2" file="sim_ibbbbeba_r_eye_2.stl" scale="0.001 0.001 0.001"/>
  </asset>

  <worldbody>
    <geom type="mesh" rgba="0.9 0.9 0.9 1" mesh="sim_sea_2-5_root_link"/>
    <body name="torso_1" pos="0 1.90735e-10 0" quat="0.5 0.5 -0.5 0.5">
      <inertial pos="-0.149722 -0.00526685 -1.4565e-05" quat="0.495921 0.497748 0.502077 0.50421" mass="0.939696" diaginertia="0.0480243 0.044061 0.004714"/>
      <joint name="torso_pitch" pos="0 0 0" axis="0 0 1" range="-0.349066 1.22173" actuatorfrcrange="-1000000000 1000000000" damping="2"/>
      <geom type="mesh" rgba="0.9 0.9 0.9 1" mesh="sim_ibbbbeba_torso_1"/>
      <body name="torso_2" pos="0.032 0 0" quat="0.707107 0.707107 0 0">
        <inertial pos="0.0364101 -8.3034e-05 -0.0009744" quat="0.507695 0.493056 0.493138 0.505921" mass="0.410506" diaginertia="0.000797056 0.000580058 0.000403069"/>
        <joint name="torso_roll" pos="0 0 0" axis="0 0 1" range="-0.523599 0.523599" actuatorfrcrange="-1000000000 1000000000" damping="2"/>
        <geom type="mesh" rgba="0.9 0.9 0.9 1" mesh="sim_ibbbbeba_torso_2"/>
        <body name="chest" pos="0 0 -0.0054975" quat="0.5 0.5 -0.5 -0.5">
          <inertial pos="-0.000982379 0.0299337 -0.122734" quat="0.519635 0.479946 -0.49522 0.504369" mass="5.91574" diaginertia="0.0341793 0.0289457 0.020048"/>
          <joint name="torso_yaw" pos="0 0 0" axis="0 0 1" range="-0.872665 0.872665" actuatorfrcrange="-1000000000 1000000000" damping="2"/>
          <geom type="mesh" rgba="0.635 0.137 0.114 1" mesh="sim_ibbbbeba_chest"/>
          <geom pos="0 0.00318967 -0.1743" quat="0.5 -0.5 0.5 -0.5" type="mesh" rgba="0.9 0.9 0.9 1" mesh="sim_ibbbbeba_neck_1"/>
          <body name="neck_2" pos="0 -0.00531033 -0.2233" quat="0.5 -0.5 0.5 -0.5">
            <inertial pos="-0.0109779 0.00938628 -0.000938235" quat="0.494012 0.510527 0.512395 0.482458" mass="0.286427" diaginertia="0.000301312 0.000235923 0.000119264"/>
            <joint name="neck_pitch" pos="0 0 0" axis="0 0 1" range="-0.698132 0.383972" actuatorfrcrange="-1000000000 1000000000" damping="2"/>
            <geom type="mesh" rgba="0.9 0.9 0.9 1" mesh="sim_ibbbbeba_neck_2"/>
            <body name="neck_3" pos="0 0.011 0" quat="0.5 0.5 0.5 0.5">
              <inertial pos="0.0359838 1.77344e-07 -0.0121321" quat="0.635154 0.311347 0.311736 0.6344" mass="0.251845" diaginertia="0.000233111 0.000221671 5.56884e-05"/>
              <joint name="neck_roll" pos="0 0 0" axis="0 0 1" range="-0.349066 0.349066" actuatorfrcrange="-1000000000 1000000000" damping="2"/>
              <geom type="mesh" rgba="0.9 0.9 0.9 1" mesh="sim_ibbbbeba_neck_3"/>
              <body name="head" pos="0 0 0" quat="0.5 -0.5 0.5 -0.5">
                <inertial pos="-0.0014791 0.00180911 0.0994676" quat="0.571256 0.780514 -0.236279 0.0929345" mass="1.477" diaginertia="0.00687311 0.00665455 0.00498635"/>
                <joint name="neck_yaw" pos="0 0 0" axis="0 0 1" range="-0.872665 0.872665" actuatorfrcrange="-1000000000 1000000000" damping="2"/>
                <geom type="mesh" rgba="1 1 1 1" mesh="sim_ibbbbeba_head"/>
                <body name="eyes_tilt_frame" pos="0 -0.051 0.0805" quat="0.5 -0.5 -0.5 0.5">
                  <inertial pos="0.0254978 -0.00339586 2.03659e-05" quat="0.781021 -0.00029173 -0.000235747 0.624505" mass="0.12521" diaginertia="0.000148063 0.000114276 5.37919e-05"/>
                  <joint name="eyes_tilt" pos="0 0 0" axis="0 0 1" range="-0.523599 0.523599" actuatorfrcrange="-1000000000 1000000000" damping="2"/>
                  <geom type="mesh" mesh="sim_ibbbbeba_eyes_1"/>
                  <body name="l_eye" pos="0 0 -0.034" quat="0.707107 -0.707107 0 0">
                    <inertial pos="-0.00247311 -4.29855e-05 -8.96154e-05" quat="0.541317 0.560981 -0.430685 0.454737" mass="0.0327656" diaginertia="5.50777e-06 5.4729e-06 4.98922e-06"/>
                    <joint name="l_eye_pan_joint" pos="0 0 0" axis="0 0 1" range="-0.785398 0.785398" actuatorfrcrange="-1000000000 1000000000" damping="2"/>
                    <geom type="mesh" mesh="sim_ibbbbeba_l_eye_2"/>
                  </body>
                  <body name="r_eye" pos="0 0 0.034" quat="0.707107 -0.707107 0 0">
                    <inertial pos="-0.00245763 -3.39373e-05 9.86837e-06" quat="0.725421 0.685262 0.0275192 -0.0585011" mass="0.0329719" diaginertia="5.54154e-06 5.52586e-06 5.03901e-06"/>
                    <joint name="r_eye_pan_joint" pos="0 0 0" axis="0 0 1" range="-0.785398 0.785398" actuatorfrcrange="-1000000000 1000000000" damping="2"/>
                    <geom type="mesh" mesh="sim_ibbbbeba_r_eye_2"/>
                  </body>
                </body>
              </body>
            </body>
          </body>
          <body name="l_shoulder_1" pos="-0.219265 -0.034563 -0.1433" quat="0.683013 0.683013 0.183013 0.183013">
            <inertial pos="0.111272 -3.33578e-05 0.0233232" quat="0.991582 0.00246211 -0.12946 5.95308e-05" mass="0.114882" diaginertia="2.34132e-05 2.29716e-05 9.06799e-06"/>
            <joint name="l_shoulder_pitch" pos="0 0 0" axis="-0.965926 0 -0.258819" range="-1.66679 0.174533" actuatorfrcrange="-1000000000 1000000000" damping="2"/>
            <geom type="mesh" rgba="0.9 0.9 0.9 1" mesh="sim_sea_2-5_l_shoulder_1"/>
            <body name="l_shoulder_2" pos="0.109633 0 0.029376" quat="0.707107 -0.183013 0 0.683013">
              <inertial pos="0.0184282 0.000268399 -0.00804329" quat="0.698885 0.106285 0.0980965 0.700457" mass="0.238162" diaginertia="0.000222588 0.000163492 0.00011617"/>
              <joint name="l_shoulder_roll" pos="0 0 0" axis="-0.258819 0 0.965926" range="0 2.80649" actuatorfrcrange="-1000000000 1000000000" damping="2"/>
              <geom pos="-0.109633 0 -0.029376" quat="1 0 0 0" type="mesh" rgba="0.9 0.9 0.9 1" mesh="sim_sea_2-5_l_shoulder_2"/>
              <body name="l_shoulder_3" pos="0.0770809 0 0.0206538" quat="0.103553 0.603553 0.0794593 0.786566">
                <inertial pos="0.0165936 -0.000737786 0.0526555" quat="0.702779 0.0481418 0.0407852 0.708605" mass="1.10593" diaginertia="0.0042947 0.00411894 0.000712066"/>
                <joint name="l_shoulder_yaw" pos="0 0 0" axis="0 0 1" range="-0.645772 1.39626" actuatorfrcrange="-1000000000 1000000000" damping="2"/>
                <geom pos="0.015 0 0" quat="1 0 0 0" type="mesh" rgba="0.9 0.9 0.9 1" mesh="sim_sea_2-5_l_upper_arm"/>
                <geom pos="0 0 -0.1933" quat="0 -0.608761 0 -0.793353" type="mesh" rgba="0.635 0.137 0.114 1" mesh="sim_sea_2-5_l_elbow"/>
                <body name="l_elbow_1" pos="0.015 0 0.07926" quat="0 -0.608761 0 -0.793353">
                  <inertial pos="0.00673917 -0.00369782 -0.0046577" quat="0.705809 0.475252 -0.434142 0.295787" mass="0.267903" diaginertia="0.000102106 7.94378e-05 5.53206e-05"/>
                  <joint name="l_elbow" pos="0 0 0" axis="0 -1 0" range="0.261799 1.85005" actuatorfrcrange="-1000000000 1000000000" damping="2"/>
                  <geom pos="-0.25939 0 -0.0850326" quat="1 0 0 0" type="mesh" rgba="0.635 0.137 0.114 1" mesh="sim_sea_2-5_l_elbow_prosup"/>
                  <body name="l_forearm" pos="-0.258425 0 -0.0847738" quat="1 0 0 0">
                    <inertial pos="0.337338 -0.000686127 0.0848743" quat="0.589221 0.393031 0.373008 0.599341" mass="0.636185" diaginertia="0.000674372 0.000605037 0.000323383"/>
                    <joint name="l_wrist_prosup" pos="0 0 0" axis="0.965926 0 0.258819" range="-1.0472 1.0472" actuatorfrcrange="-1000000000 1000000000" damping="2"/>
                    <geom type="mesh" rgba="0.635 0.137 0.114 1" mesh="sim_sea_2-5_l_forearm"/>
                    <body name="l_wrist_1" pos="0.399758 7.03721e-06 0.107115" quat="1 0 0 0">
                      <inertial pos="-0.000424614 -0.00117775 0.00200678" quat="0.992765 -0.021161 -0.117794 -0.00973778" mass="0.0362152" diaginertia="5.79438e-06 5.29545e-06 1.64209e-06"/>
                      <joint name="l_wrist_pitch" pos="0 0 0" axis="0.258819 0 -0.965926" range="-1.39626 0.436332" actuatorfrcrange="-1000000000 1000000000" damping="2"/>
                      <geom pos="-0.399758 -7.03721e-06 -0.107115" type="mesh" rgba="0.9 0.9 0.9 1" mesh="sim_sea_2-5_l_wrist_pitch"/>
                      <body name="l_hand" pos="-7.76457e-05 -7.03721e-06 0.000289778" quat="1 0 0 0">
                        <inertial pos="0.064768 -0.0138626 0.0226602" quat="0.517226 0.476361 0.391125 0.593783" mass="0.247806" diaginertia="0.000434001 0.000310604 0.000153272"/>
                        <joint name="l_wrist_yaw" pos="0 0 0" axis="0 1 0" range="-0.349066 0.436332" actuatorfrcrange="-1000000000 1000000000" damping="2"/>
                        <geom pos="-0.39968 0 -0.107405" quat="1 0 0 0" type="mesh" rgba="0.9 0.9 0.9 1" mesh="sim_sea_2-5_l_hand"/>
                      </body>
                    </body>
                  </body>
                </body>
              </body>
            </body>
          </body>
          <body name="r_shoulder_1" pos="0.219265 -0.034563 -0.1433" quat="0.683013 0.683013 -0.183013 -0.183013">
            <inertial pos="-0.111274 3.18706e-05 0.0233186" quat="0.991582 -0.00229881 0.129459 5.19146e-05" mass="0.114862" diaginertia="2.33988e-05 2.29585e-05 9.06656e-06"/>
            <joint name="r_shoulder_pitch" pos="0 0 0" axis="-0.965926 0 0.258819" range="-1.66679 0.174533" actuatorfrcrange="-1000000000 1000000000" damping="2"/>
            <geom type="mesh" rgba="0.9 0.9 0.9 1" mesh="sim_sea_2-5_r_shoulder_1"/>
            <body name="r_shoulder_2" pos="-0.109633 0 0.029376" quat="0.707107 -0.183013 0 -0.683013">
              <inertial pos="-0.0183698 0.000271524 -0.00807692" quat="0.704599 -0.060286 -0.0685902 0.703705" mass="0.238162" diaginertia="0.00020654 0.000160519 0.000103048"/>
              <joint name="r_shoulder_roll" pos="0 0 0" axis="-0.258819 0 -0.965926" range="0 2.80649" actuatorfrcrange="-1000000000 1000000000" damping="2"/>
              <geom pos="0.109633 0 -0.029376" quat="1 0 0 0" type="mesh" rgba="0.9 0.9 0.9 1" mesh="sim_sea_2-5_r_shoulder_2"/>
              <body name="r_shoulder_3" pos="-0.0770809 0 0.0206538" quat="0.786566 -0.0794593 -0.603553 0.103553">
                <inertial pos="-0.270532 0.00116235 0.0192268" quat="0.457352 0.541581 0.536863 0.45749" mass="1.10423" diaginertia="0.0430818 0.0429153 0.000703143"/>
                <joint name="r_shoulder_yaw" pos="0 0 0" axis="0 0 -1" range="-0.645772 1.39626" actuatorfrcrange="-1000000000 1000000000" damping="2"/>
                <geom pos="0.015 0 0" quat="1 0 0 0" type="mesh" rgba="0.9 0.9 0.9 1" mesh="sim_sea_2-5_r_upper_arm"/>
                <geom pos="0 0 -0.1933" quat="0.793353 0 0.608761 0" type="mesh" rgba="0.635 0.137 0.114 1" mesh="sim_sea_2-5_r_elbow"/>
                <body name="r_elbow_1" pos="0.015 0 0.07926" quat="0.793353 0 0.608761 0">
                  <inertial pos="-0.00673917 -0.00369782 -0.0046577" quat="0.295629 0.434098 -0.475293 0.705875" mass="0.267903" diaginertia="0.000102099 7.94315e-05 5.53338e-05"/>
                  <joint name="r_elbow" pos="0 0 0" axis="0 1 0" range="0.261799 1.85005" actuatorfrcrange="-1000000000 1000000000" damping="2"/>
                  <geom pos="0.25939 0 -0.0850326" quat="1 0 0 0" type="mesh" rgba="0.635 0.137 0.114 1" mesh="sim_sea_2-5_r_elbow_prosup"/>
                  <body name="r_forearm" pos="0.258425 0 -0.0847738" quat="1 0 0 0">
                    <inertial pos="-0.337326 -0.000327853 0.084878" quat="0.380022 0.595027 0.594184 0.385319" mass="0.6347" diaginertia="0.000672292 0.000601594 0.000322074"/>
                    <joint name="r_wrist_prosup" pos="0 0 0" axis="0.965926 0 -0.258819" range="-1.0472 1.0472" actuatorfrcrange="-1000000000 1000000000" damping="2"/>
                    <geom type="mesh" rgba="0.635 0.137 0.114 1" mesh="sim_sea_2-5_r_forearm"/>
                    <body name="r_wrist_1" pos="-0.399758 7.03721e-06 0.107115" quat="1 0 0 0">
                      <inertial pos="0.00035189 -0.00117624 0.00173483" quat="0.992759 -0.021213 0.117832 0.00973049" mass="0.0362615" diaginertia="5.8045e-06 5.30557e-06 1.64283e-06"/>
                      <joint name="r_wrist_pitch" pos="0 0 0" axis="0.258819 0 0.965926" range="-1.39626 0.436332" actuatorfrcrange="-1000000000 1000000000" damping="2"/>
                      <geom pos="0.399758 -7.03721e-06 -0.107115" type="mesh" rgba="0.9 0.9 0.9 1" mesh="sim_sea_2-5_r_wrist_pitch"/>
                      <body name="r_hand" pos="0 -7.03721e-06 0">
                        <inertial pos="-0.0646681 -0.0138928 0.0226813" quat="0.393073 0.593285 0.514992 0.477797" mass="0.248289" diaginertia="0.000434751 0.000311161 0.000153598"/>
                        <joint name="r_wrist_yaw" pos="0 0 0" axis="0 -1 0" range="-0.349066 0.436332" actuatorfrcrange="-1000000000 1000000000" damping="2"/>
                        <geom pos="0.399758 0 -0.107115" quat="1 0 0 0" type="mesh" rgba="0.9 0.9 0.9 1" mesh="sim_sea_2-5_r_hand"/>
                      </body>
                    </body>
                  </body>
                </body>
              </body>
            </body>
          </body>
        </body>
      </body>
    </body>
    <body name="l_hip_1" pos="0.00645153 -0.026 -0.119913" quat="0 0 0 1">
      <inertial pos="-0.000510787 0.0380923 -8.21863e-05" quat="0.706519 0.701948 0.0614487 -0.0657565" mass="0.919725" diaginertia="0.000579182 0.000573129 0.000404525"/>
      <joint name="l_hip_pitch" pos="0 0 0" axis="0 -1 0" range="-0.785398 2.33874" actuatorfrcrange="-1000000000 1000000000" damping="2"/>
      <geom type="mesh" rgba="0.9 0.9 0.9 1" mesh="sim_sea_2-5_l_hip_1"/>
      <body name="l_hip_2" pos="-1.90735e-10 0.0441 0" quat="1 0 0 0">
        <inertial pos="-0.0181638 0.000493136 -0.032391" quat="0.327262 0.63337 0.625595 0.316818" mass="0.542199" diaginertia="0.00129402 0.00112999 0.000332964"/>
        <joint name="l_hip_roll" pos="0 0 0" axis="1 0 0" range="-0.349066 2.0944" actuatorfrcrange="-1000000000 1000000000" damping="2"/>
        <geom type="mesh" rgba="0.9 0.9 0.9 1" mesh="sim_sea_2-5_l_hip_2"/>
        <geom pos="-0.000830138 7.51754e-05 -0.0743" quat="0 -1 0 0" type="mesh" rgba="0.635 0.137 0.114 1" mesh="sim_sea_2-5_l_upper_thigh"/>
        <body name="l_upper_leg" pos="-0.000830138 7.51754e-05 -0.0887" quat="1 0 0 0">
          <inertial pos="0.00338688 0.000101778 -0.0789154" quat="0.681542 0.00155126 0.0183286 0.731547" mass="1.8084" diaginertia="0.00801016 0.00799984 0.00179716"/>
          <joint name="l_hip_yaw" pos="0 0 0" axis="0 0 1" range="-1.39626 1.39626" actuatorfrcrange="-1000000000 1000000000" damping="2"/>
          <geom type="mesh" rgba="0.635 0.137 0.114 1" mesh="sim_sea_2-5_l_thigh"/>
          <body name="l_lower_leg" pos="0 -1.90732e-10 -0.145825" quat="1 0 0 0">
            <inertial pos="0.000999724 0.00349693 -0.0885663" quat="0.991172 -0.0377012 0.0415109 0.120142" mass="1.4724" diaginertia="0.00589419 0.00541796 0.00189878"/>
            <joint name="l_knee" pos="0 0 0" axis="0 -1 0" range="-2.16421 0.0698132" actuatorfrcrange="-1000000000 1000000000" damping="2"/>
            <geom type="mesh" rgba="0.635 0.137 0.114 1" mesh="sim_sea_2-5_l_shank"/>
            <body name="l_ankle_1" pos="0 0 -0.2005" quat="1 0 0 0">
              <inertial pos="0.0151531 0.000902067 4.28855e-05" quat="0.0942726 0.706107 -0.103691 0.694099" mass="0.6798" diaginertia="0.00058243 0.000537327 0.000388464"/>
              <joint name="l_ankle_pitch" pos="0 0 0" axis="0 1 0" range="-0.872665 0.349066" actuatorfrcrange="-1000000000 1000000000" damping="2"/>
              <geom type="mesh" rgba="0.9 0.9 0.9 1" mesh="sim_sea_2-5_l_ankle"/>
              <body name="l_ankle_2" pos="-1.90737e-10 0 0" quat="1 0 0 0">
                <inertial pos="-0.015334 -0.00535982 -0.0182769" quat="0.291959 0.643956 0.386814 0.591993" mass="0.64809" diaginertia="0.00187605 0.00179742 0.000593536"/>
                <joint name="l_ankle_roll" pos="0 0 0" axis="1 0 0" range="-0.436332 0.436332" actuatorfrcrange="-1000000000 1000000000" damping="2"/>
                <geom type="mesh" rgba="0.9 0.9 0.9 1" mesh="sim_sea_2-5_l_foot"/>
                <geom size="0.08 0.036 0.0005" pos="0.0265 0.005 -0.0745" quat="0 1 0 0" type="box" rgba="0.635 0.137 0.114 1"/>
              </body>
            </body>
          </body>
        </body>
      </body>
    </body>
    <body name="r_hip_1" pos="0.00645153 0.026 -0.119913" quat="0 0 0 1">
      <inertial pos="-0.000514511 -0.0380753 -7.02939e-05" quat="0.702833 0.707742 0.0529771 -0.0481692" mass="0.919978" diaginertia="0.000580144 0.000574638 0.000404252"/>
      <joint name="r_hip_pitch" pos="0 0 0" axis="0 -1 0" range="-0.785398 2.33874" actuatorfrcrange="-1000000000 1000000000" damping="2"/>
      <geom type="mesh" rgba="0.9 0.9 0.9 1" mesh="sim_sea_2-5_r_hip_1"/>
      <body name="r_hip_2" pos="-1.90736e-10 -0.0441 0" quat="1 0 0 0">
        <inertial pos="-0.0181162 0.000502575 -0.0325341" quat="0.328448 0.632777 0.625527 0.316909" mass="0.539454" diaginertia="0.00128999 0.00112619 0.000332659"/>
        <joint name="r_hip_roll" pos="0 0 0" axis="-1 0 0" range="-0.349066 2.0944" actuatorfrcrange="-1000000000 1000000000" damping="2"/>
        <geom type="mesh" rgba="0.9 0.9 0.9 1" mesh="sim_sea_2-5_r_hip_2"/>
        <geom pos="-0.000936285 1.38919e-05 -0.0743" quat="0 -1 0 0" type="mesh" rgba="0.635 0.137 0.114 1" mesh="sim_sea_2-5_r_upper_thigh"/>
        <body name="r_upper_leg" pos="-0.000936285 1.38919e-05 -0.0887" quat="-1 0 0 0">
          <inertial pos="0.00339998 -2.91067e-05 -0.0789538" quat="0.769981 0.0186284 0.00226523 0.637791" mass="1.8035" diaginertia="0.00800564 0.00799246 0.0017939"/>
          <joint name="r_hip_yaw" pos="0 0 0" axis="0 0 -1" range="-1.39626 1.39626" actuatorfrcrange="-1000000000 1000000000" damping="2"/>
          <geom type="mesh" rgba="0.635 0.137 0.114 1" mesh="sim_sea_2-5_r_thigh"/>
          <body name="r_lower_leg" pos="0 1.90734e-10 -0.145825" quat="1 0 0 0">
            <inertial pos="0.00123637 -0.00351311 -0.0887934" quat="0.992735 0.0357731 0.045782 -0.10536" mass="1.472" diaginertia="0.00589903 0.00542602 0.00189324"/>
            <joint name="r_knee" pos="0 0 0" axis="0 -1 0" range="-2.16421 0.0698132" actuatorfrcrange="-1000000000 1000000000" damping="2"/>
            <geom type="mesh" rgba="0.635 0.137 0.114 1" mesh="sim_sea_2-5_r_shank"/>
            <body name="r_ankle_1" pos="0 0 -0.2005" quat="1 0 0 0">
              <inertial pos="0.0151436 -0.000868555 4.28587e-05" quat="-0.0974687 0.706465 0.09946 0.693913" mass="0.6803" diaginertia="0.000583325 0.00053728 0.000389429"/>
              <joint name="r_ankle_pitch" pos="0 0 0" axis="0 1 0" range="-0.872665 0.349066" actuatorfrcrange="-1000000000 1000000000" damping="2"/>
              <geom type="mesh" rgba="0.9 0.9 0.9 1" mesh="sim_sea_2-5_r_ankle"/>
              <body name="r_ankle_2" pos="-1.90735e-10 0 0" quat="1 0 0 0">
                <inertial pos="-0.0153717 0.00536542 -0.0182638" quat="0.591919 0.386738 0.644277 0.2915" mass="0.647988" diaginertia="0.00187401 0.00179539 0.000593313"/>
                <joint name="r_ankle_roll" pos="0 0 0" axis="-1 0 0" range="-0.436332 0.436332" actuatorfrcrange="-1000000000 1000000000" damping="2"/>
                <geom type="mesh" rgba="0.9 0.9 0.9 1" mesh="sim_sea_2-5_r_foot"/>
                <geom size="0.08 0.036 0.0005" pos="0.0265 -0.005 -0.0745" quat="0 -1 0 0" type="box" rgba="0.635 0.137 0.114 1"/>
              </body>
            </body>
          </body>
        </body>
      </body>
    </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.