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I get the error

ValueError: XML Error: global coordinates no longer supported. To convert existing models, load and save them in MuJoCo 2.3.3 or older

When i try to load the walker2d-v4 model even with **kwargs.

env = gym.make(
    'Walker2d-v4',
    # xml_file="walker2d.xml",
    forward_reward_weight=1.0,
    ctrl_cost_weight=1e-3,
    healthy_reward=1.0,
    terminate_when_unhealthy=True,
    healthy_z_range=(0.8, 2),
    healthy_angle_range=(-1, 1),
    reset_noise_scale=5e-3,
    exclude_current_positions_from_observation=True
)

Anyone face similar issues?

Here's the solution to this, thanks to @yuval for pointing it out.

you need to load the walker2d.xml with this error into a model. For this you need to install mujoco 2.3.3 and then run the following code,

model = mujoco.MjModel.from_xml_path('walker2d.xml')
mujoco.viewer.launch(model)

This should open up a mujoco viewer window that has an option to "save XML" - this should save the updated xml file as mjmodel.xml in the current dir. just copy paste that into walker2d.xml and your gym code should now be working.

Walker2D XML that worked for me

<mujoco model="walker2d">
  <compiler angle="radian" autolimits="true"/>
  <option integrator="RK4"/>
  <default class="main">
    <joint limited="true" armature="0.01" damping="0.1"/>
    <geom conaffinity="0" friction="0.7 0.1 0.1" rgba="0.8 0.6 0.4 1"/>
  </default>
  <asset>
    <texture type="skybox" builtin="gradient" rgb1="0.4 0.5 0.6" rgb2="0 0 0" width="100" height="600"/>
    <texture type="cube" name="texgeom" builtin="flat" mark="cross" rgb1="0.8 0.6 0.4" rgb2="0.8 0.6 0.4" markrgb="1 1 1" width="127" height="762"/>
    <texture type="2d" name="texplane" builtin="checker" rgb1="0 0 0" rgb2="0.8 0.8 0.8" width="100" height="100"/>
    <material name="MatPlane" texture="texplane" texrepeat="60 60" specular="1" shininess="1" reflectance="0.5"/>
    <material name="geom" texture="texgeom" texuniform="true"/>
  </asset>
  <worldbody>
    <geom name="floor" size="40 40 40" type="plane" conaffinity="1" material="MatPlane" rgba="0.8 0.9 0.8 1"/>
    <light pos="0 0 1.3" dir="0 0 -1" directional="true" cutoff="100" exponent="1" diffuse="1 1 1" specular="0.1 0.1 0.1"/>
    <body name="torso" pos="0 0 1.25" gravcomp="0">
      <joint name="rootx" pos="0 0 -1.25" axis="1 0 0" limited="false" type="slide" armature="0" damping="0"/>
      <joint name="rootz" pos="0 0 -1.25" axis="0 0 1" limited="false" type="slide" ref="1.25" armature="0" damping="0"/>
      <joint name="rooty" pos="0 0 0" axis="0 1 0" limited="false" armature="0" damping="0"/>
      <geom name="torso_geom" size="0.05 0.2" type="capsule" friction="0.9 0.1 0.1"/>
      <camera name="track" pos="0 -3 -0.25" quat="0.707107 0.707107 0 0" mode="trackcom"/>
      <body name="thigh" pos="0 0 -0.2" gravcomp="0">
        <joint name="thigh_joint" pos="0 0 0" axis="0 -1 0" range="-2.61799 0"/>
        <geom name="thigh_geom" size="0.05 0.225" pos="0 0 -0.225" type="capsule" friction="0.9 0.1 0.1"/>
        <body name="leg" pos="0 0 -0.7" gravcomp="0">
          <joint name="leg_joint" pos="0 0 0.25" axis="0 -1 0" range="-2.61799 0"/>
          <geom name="leg_geom" size="0.04 0.25" type="capsule" friction="0.9 0.1 0.1"/>
          <body name="foot" pos="0.2 0 -0.35" gravcomp="0">
            <joint name="foot_joint" pos="-0.2 0 0.1" axis="0 -1 0" range="-0.785398 0.785398"/>
            <geom name="foot_geom" size="0.06 0.1" pos="-0.1 0 0.1" quat="0.707107 0 -0.707107 0" type="capsule" friction="0.9 0.1 0.1"/>
          </body>
        </body>
      </body>
      <body name="thigh_left" pos="0 0 -0.2" gravcomp="0">
        <joint name="thigh_left_joint" pos="0 0 0" axis="0 -1 0" range="-2.61799 0"/>
        <geom name="thigh_left_geom" size="0.05 0.225" pos="0 0 -0.225" type="capsule" friction="0.9 0.1 0.1" rgba="0.7 0.3 0.6 1"/>
        <body name="leg_left" pos="0 0 -0.7" gravcomp="0">
          <joint name="leg_left_joint" pos="0 0 0.25" axis="0 -1 0" range="-2.61799 0"/>
          <geom name="leg_left_geom" size="0.04 0.25" type="capsule" friction="0.9 0.1 0.1" rgba="0.7 0.3 0.6 1"/>
          <body name="foot_left" pos="0.2 0 -0.35" gravcomp="0">
            <joint name="foot_left_joint" pos="-0.2 0 0.1" axis="0 -1 0" range="-0.785398 0.785398"/>
            <geom name="foot_left_geom" size="0.06 0.1" pos="-0.1 0 0.1" quat="0.707107 0 -0.707107 0" type="capsule" friction="1.9 0.1 0.1" rgba="0.7 0.3 0.6 1"/>
          </body>
        </body>
      </body>
    </body>
  </worldbody>
  <actuator>
    <general joint="thigh_joint" ctrlrange="-1 1" gear="100 0 0 0 0 0" actdim="0"/>
    <general joint="leg_joint" ctrlrange="-1 1" gear="100 0 0 0 0 0" actdim="0"/>
    <general joint="foot_joint" ctrlrange="-1 1" gear="100 0 0 0 0 0" actdim="0"/>
    <general joint="thigh_left_joint" ctrlrange="-1 1" gear="100 0 0 0 0 0" actdim="0"/>
    <general joint="leg_left_joint" ctrlrange="-1 1" gear="100 0 0 0 0 0" actdim="0"/>
    <general joint="foot_left_joint" ctrlrange="-1 1" gear="100 0 0 0 0 0" actdim="0"/>
  </actuator>
</mujoco>
SKrish
  • 43
  • 6

2 Answers2

2

See this issue and links therein.

yuval
  • 109
  • 2
  • Thanks. I figured it out. I was relatively new to mujoco and openai-gym but the python bindings made it easy. I put the solution file at the end of my question. – SKrish May 16 '23 at 20:42
1

I am a Developer of Gymnasium

This issue will be fixed on v29

pip install gymansium>=0.29

If you need to use an older version we would recommend installing a MuJoCo version that is compatible:

pip install mujoco==2.3.3

Note: do not use the MuJoCo model in the OP, its behavior is not identical to the original.

Kallinteris Andreas
  • 11
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