Updates the URDF and MJCF importers for Isaac Sim 4.5 (#182)

Updates the URDF and MJCF importers for Isaac Sim 4.5.

- New feature (non-breaking change which adds functionality)

- [x] I have run the [`pre-commit` checks](https://pre-commit.com/) with
`./isaaclab.sh --format`
- [x] I have made corresponding changes to the documentation
- [x] My changes generate no new warnings
- [x] I have added tests that prove my fix is effective or that my
feature works
- [x] I have updated the changelog and the corresponding version in the
extension's `config/extension.toml` file
- [x] I have added my name to the `CONTRIBUTORS.md` or my name already
exists there

---------
Co-authored-by: Kelly Guo <kellyg@nvidia.com>
Co-authored-by: Kelly Guo <kellyguo123@hotmail.com>

docs/source/how-to/import_new_asset.rst

@@ -37,23 +37,30 @@ For using the URDF importer in the GUI, please check the documentation at `URDF
 is then passed to the :class:`~sim.converters.UrdfConverter` class.
 
 The URDF importer has various configuration parameters that can be set to control the behavior of the importer.
-The default values for the importer's configuration parameters are specified are in the :class:`~sim.converters.UrdfConverterCfg` class, and they are listed below. We made a few commonly modified settings to be available as command-line arguments when calling the ``convert_urdf.py``, and they are marked with ``*``` in the list. For a comprehensive list of the configuration parameters, please check the the documentation at `URDF importer`_.
+The default values for the importer's configuration parameters are specified are in the :class:`~sim.converters.UrdfConverterCfg` class, and they are listed below. We made a few commonly modified settings to be available as command-line arguments when calling the ``convert_urdf.py``, and they are marked with ``*`` in the list. For a comprehensive list of the configuration parameters, please check the the documentation at `URDF importer`_.
 
-* :attr:`~sim.converters.UrdfConverterCfg.fix_base*` - Whether to fix the base of the robot.
+* :attr:`~sim.converters.UrdfConverterCfg.fix_base` * - Whether to fix the base of the robot.
   This depends on whether you have a floating-base or fixed-base robot. The command-line flag is
   ``--fix-base`` where when set, the importer will fix the base of the robot, otherwise it will default to floating-base.
-* :attr:`~sim.converters.UrdfConverterCfg.merge_fixed_joints*` - Whether to merge the fixed joints.
+* :attr:`~sim.converters.UrdfConverterCfg.root_link_name` - The link on which the PhysX articulation root is placed.
+* :attr:`~sim.converters.UrdfConverterCfg.merge_fixed_joints` * - Whether to merge the fixed joints.
   Usually, this should be set to ``True`` to reduce the asset complexity. The command-line flag is
   ``--merge-joints`` where when set, the importer will merge the fixed joints, otherwise it will default to not merging the fixed joints.
-* :attr:`~sim.converters.UrdfConverterCfg.default_drive_type` - The drive-type for the joints.
-  We recommend this to always be ``"none"``. This allows changing the drive configuration using the
-  actuator models.
-* :attr:`~sim.converters.UrdfConverterCfg.default_drive_stiffness` - The drive stiffness for the joints.
-  We recommend this to always be ``0.0``. This allows changing the drive configuration using the
-  actuator models.
-* :attr:`~sim.converters.UrdfConverterCfg.default_drive_damping` - The drive damping for the joints.
-  Similar to the stiffness, we recommend this to always be ``0.0``.
+* :attr:`~sim.converters.UrdfConverterCfg.joint_drive` - The configuration for the joint drives on the robot.
 
+  * :attr:`~sim.converters.UrdfConverterCfg.JointDriveCfg.drive_type` - The drive type for the joints.
+    This can be either ``"acceleration"`` or ``"force"``. We recommend using ``"force"`` for most cases.
+  * :attr:`~sim.converters.UrdfConverterCfg.JointDriveCfg.target_type` - The target type for the joints.
+    This can be either ``"none"``, ``"position"``, or ``"velocity"``. We recommend using ``"position"`` for most cases.
+    Setting this to ``"none"`` will disable the drive and set the joint gains to 0.0.
+  * :attr:`~sim.converters.UrdfConverterCfg.JointDriveCfg.gains` - The drive stiffness and damping gains for the joint.
+    We support two ways to set the gains:
+
+    * :attr:`~sim.converters.UrdfConverterCfg.JointDriveCfg.PDGainsCfg` - To directly set the stiffness and damping.
+    * :attr:`~sim.converters.UrdfConverterCfg.JointDriveCfg.NaturalFrequencyGainsCfg` - To set the gains using the
+      desired natural frequency response of the system.
+
+For more detailed information on the configuration parameters, please check the documentation for :class:`~sim.converters.UrdfConverterCfg`.
 
 Example Usage
 ~~~~~~~~~~~~~

source/extensions/omni.isaac.lab/config/extension.toml

 [package]
 
 # Note: Semantic Versioning is used: https://semver.org/
-version = "0.30.7"
+version = "0.31.7"
 
 # Description
 title = "Isaac Lab framework for Robot Learning"

source/extensions/omni.isaac.lab/docs/CHANGELOG.rst

 Changelog
 ---------
 
-0.30.7 (2025-01-30)
+0.31.7 (2025-01-30)
 ~~~~~~~~~~~~~~~~~~~
 
 Fixed
@@ -12,7 +12,7 @@ Fixed
   to the event being triggered at the wrong time after the reset.
 
 
-0.30.6 (2025-01-17)
+0.31.6 (2025-01-17)
 ~~~~~~~~~~~~~~~~~~~
 
 Fixed
@@ -42,7 +42,7 @@ Fixed
   the :class:`omni.isaac.lab.assets.RigidObjectCollection` class.
 
 
-0.30.5 (2025-01-14)
+0.31.5 (2025-01-14)
 ~~~~~~~~~~~~~~~~~~~
 
 Fixed
@@ -51,17 +51,17 @@ Fixed
 * Fixed the respawn of only wrong object samples in :func:`repeated_objects_terrain` of :mod:`omni.isaac.lab.terrains.trimesh` module. Previously, the function was respawning all objects in the scene instead of only the wrong object samples, which in worst case could lead to infinite respawn loop.
 
 
-0.30.4 (2025-01-08)
+0.31.4 (2025-01-08)
 ~~~~~~~~~~~~~~~~~~~
 
 Fixed
 ^^^^^
 
-* fixed docstring in articulation data :class:`omni.isaac.lab.assets.ArticulationData`.
+* Fixed docstring in articulation data :class:`omni.isaac.lab.assets.ArticulationData`.
   In body properties sections, the second dimension should be num_bodies but was documented as 1.
 
 
-0.30.3 (2025-01-02)
+0.31.3 (2025-01-02)
 ~~~~~~~~~~~~~~~~~~~
 
 Added
@@ -70,7 +70,7 @@ Added
 * Added body tracking as an origin type to :class:`omni.isaac.lab.envs.ViewerCfg` and :class:`omni.isaac.lab.envs.ui.ViewportCameraController`.
 
 
-0.30.2 (2024-12-22)
+0.31.2 (2024-12-22)
 ~~~~~~~~~~~~~~~~~~~
 
 Fixed
@@ -79,7 +79,7 @@ Fixed
 * Fixed populating default_joint_stiffness and default_joint_damping values for ImplicitActuator instances in :class:`omni.isaac.lab.assets.Articulation`
 
 
-0.30.1 (2024-12-17)
+0.31.1 (2024-12-17)
 ~~~~~~~~~~~~~~~~~~~
 
 Added
@@ -93,7 +93,7 @@ Added
   :class:`omni.isaac.lab.envs.mdp.actions.OperationalSpaceControllerAction` class.
 
 
-0.30.0 (2024-12-16)
+0.31.0 (2024-12-16)
 ~~~~~~~~~~~~~~~~~~~
 
 Changed
@@ -102,7 +102,7 @@ Changed
 * Previously, physx returns the rigid bodies and articulations velocities in the com of bodies rather than the link frame, while poses are in link frames. We now explicitly provide :attr:`body_link_state` and :attr:`body_com_state` APIs replacing the previous :attr:`body_state` API. Previous APIs are now marked as deprecated. Please update any code using the previous pose and velocity APIs to use the new ``*_link_*`` or ``*_com_*`` APIs in :attr:`omni.isaac_lab.assets.RigidBody`, :attr:`omni.isaac_lab.assets.RigidBodyCollection`, and :attr:`omni.isaac_lab.assets.Articulation`.
 
 
-0.29.3 (2024-12-16)
+0.30.3 (2024-12-16)
 ~~~~~~~~~~~~~~~~~~~
 
 Fixed
@@ -111,7 +111,7 @@ Fixed
 * Fixed ordering of logging and resamping in the command manager, where we were logging the metrics after resampling the commands. This leads to incorrect logging of metrics when inside the resample call, the metrics tensors get reset.
 
 
-0.29.2 (2024-12-16)
+0.30.2 (2024-12-16)
 ~~~~~~~~~~~~~~~~~~~
 
 Fixed
@@ -128,7 +128,7 @@ Added
 * Added the implementation of :class:`omni.isaac.lab.envs.mdp.actions.OperationalSpaceControllerAction` class.
 
 
-0.29.1 (2024-12-15)
+0.30.1 (2024-12-15)
 ~~~~~~~~~~~~~~~~~~~
 
 Changed
@@ -137,7 +137,7 @@ Changed
 * Added call to update articulation kinematics after reset to ensure states are updated for non-rendering sensors. Previously, some changes in reset such as modifying joint states would not be reflected in the rigid body states immediately after reset.
 
 
-0.29.0 (2024-12-15)
+0.30.0 (2024-12-15)
 ~~~~~~~~~~~~~~~~~~~
 
 Added
@@ -151,7 +151,7 @@ Added
 * Additions to :class:`BaseEnvWindow` and :class:`RLEnvWindow` to register ManagerLiveVisualizer UI interfaces for the chosen managers.
 
 
-0.28.0 (2024-12-15)
+0.29.0 (2024-12-15)
 ~~~~~~~~~~~~~~~~~~~
 
 Added
@@ -163,8 +163,8 @@ Added
 * Added full buffer property to :class:`omni.isaac.lab.utils.buffers.circular_buffer.CircularBuffer`
 
 
-0.27.36 (2024-12-15)
-~~~~~~~~~~~~~~~~~~~~
+0.28.3 (2024-12-15)
+~~~~~~~~~~~~~~~~~~~
 
 Added
 ^^^^^
@@ -172,8 +172,8 @@ Added
 * Added action clip to all :class:`omni.isaac.lab.envs.mdp.actions`.
 
 
-0.27.35 (2024-12-14)
-~~~~~~~~~~~~~~~~~~~~
+0.28.2 (2024-12-14)
+~~~~~~~~~~~~~~~~~~~
 
 Changed
 ^^^^^^^
@@ -181,8 +181,8 @@ Changed
 * Added check for error below threshold in state machines to ensure the state has been reached.
 
 
-0.27.34 (2024-12-13)
-~~~~~~~~~~~~~~~~~~~~
+0.28.1 (2024-12-13)
+~~~~~~~~~~~~~~~~~~~
 
 Fixed
 ^^^^^
@@ -190,12 +190,22 @@ Fixed
 * Fixed the shape of ``quat_w`` in the ``apply_actions`` method of :attr:`~omni.isaac.lab.env.mdp.NonHolonomicAction` (previously (N,B,4), now (N,4) since the number of root bodies B is required to be 1). Previously ``apply_actions`` errored because ``euler_xyz_from_quat`` requires inputs of shape (N,4).
 
 
-0.27.33 (2024-12-11)
-~~~~~~~~~~~~~~~~~~~~
+0.28.0 (2024-12-12)
+~~~~~~~~~~~~~~~~~~~
 
 Changed
 ^^^^^^^
 
+* Adapted the :class:`~omni.isaac.lab.sim.converters.UrdfConverter` to use the latest URDF converter API from Isaac Sim 4.5. The
+  physics articulation root can now be set separately, and the joint drive gains can be set on a per joint basis.
+
+
+0.27.33 (2024-12-11)
+~~~~~~~~~~~~~~~~~~~~
+
+Added
+^^^^^
+
 * Introduced an optional ``sensor_cfg`` parameter to the :meth:`~omni.isaac.lab.envs.mdp.rewards.base_height_l2` function, enabling the use of
   :class:`~omni.isaac.lab.sensors.RayCaster` for height adjustments. For flat terrains, the function retains its previous behavior.
 * Improved documentation to clarify the usage of the :meth:`~omni.isaac.lab.envs.mdp.rewards.base_height_l2` function in both flat and rough terrain settings.

source/extensions/omni.isaac.lab/omni/isaac/lab/sim/converters/mjcf_converter.py

@@ -10,8 +10,6 @@ import os
 import isaacsim
 import omni.kit.commands
 import omni.usd
-from isaacsim.core.utils.extensions import enable_extension
-from pxr import Usd
 
 from .asset_converter_base import AssetConverterBase
 from .mjcf_converter_cfg import MjcfConverterCfg
@@ -57,47 +55,24 @@ class MjcfConverter(AssetConverterBase):
         Args:
             cfg: The configuration instance for MJCF to USD conversion.
         """
-        import_config = self._get_mjcf_import_config(cfg)
+        import_config = self._get_mjcf_import_config()
+        file_basename, _ = os.path.basename(cfg.asset_path).split(".")
         omni.kit.commands.execute(
             "MJCFCreateAsset",
             mjcf_path=cfg.asset_path,
             import_config=import_config,
             dest_path=self.usd_path,
+            prim_path=f"/{file_basename}",
         )
 
-        # fix the issue that material paths are not relative
-        if self.cfg.make_instanceable:
-            instanced_usd_path = os.path.join(self.usd_dir, self.usd_instanceable_meshes_path)
-            stage = Usd.Stage.Open(instanced_usd_path)
-            # resolve all paths relative to layer path
-            source_layer = stage.GetRootLayer()
-            omni.usd.resolve_paths(source_layer.identifier, source_layer.identifier)
-            stage.Save()
-
-        # fix the issue that material paths are not relative
-        # note: This issue seems to have popped up in Isaac Sim 2023.1.1
-        stage = Usd.Stage.Open(self.usd_path)
-        # resolve all paths relative to layer path
-        source_layer = stage.GetRootLayer()
-        omni.usd.resolve_paths(source_layer.identifier, source_layer.identifier)
-        stage.Save()
-
-    def _get_mjcf_import_config(self, cfg: MjcfConverterCfg) -> isaacsim.asset.importer.mjcf.ImportConfig:
+    def _get_mjcf_import_config(self) -> isaacsim.asset.importer.mjcf.ImportConfig:
         """Returns the import configuration for MJCF to USD conversion.
 
-        Args:
-            cfg: The configuration instance for MJCF to USD conversion.
-
         Returns:
             The constructed ``ImportConfig`` object containing the desired settings.
         """
 
-        # Enable MJCF Extensions
-        enable_extension("isaacsim.asset.importer.mjcf")
-
-        from isaacsim.asset.importer.mjcf import _mjcf as omni_mjcf
-
-        import_config = omni_mjcf.ImportConfig()
+        _, import_config = omni.kit.commands.execute("MJCFCreateImportConfig")
 
         # set the unit scaling factor, 1.0 means meters, 100.0 means cm
         # import_config.set_distance_scale(1.0)
@@ -110,19 +85,19 @@ class MjcfConverter(AssetConverterBase):
 
         # -- instancing settings
         # meshes will be placed in a separate usd file
-        import_config.set_make_instanceable(cfg.make_instanceable)
+        import_config.set_make_instanceable(self.cfg.make_instanceable)
         import_config.set_instanceable_usd_path(self.usd_instanceable_meshes_path)
 
         # -- asset settings
         # default density used for links, use 0 to auto-compute
-        import_config.set_density(cfg.link_density)
+        import_config.set_density(self.cfg.link_density)
         # import inertia tensor from urdf, if it is not specified in urdf it will import as identity
-        import_config.set_import_inertia_tensor(cfg.import_inertia_tensor)
+        import_config.set_import_inertia_tensor(self.cfg.import_inertia_tensor)
 
         # -- physics settings
         # create fix joint for base link
-        import_config.set_fix_base(cfg.fix_base)
+        import_config.set_fix_base(self.cfg.fix_base)
         # self collisions between links in the articulation
-        import_config.set_self_collision(cfg.self_collision)
+        import_config.set_self_collision(self.cfg.self_collision)
 
         return import_config

source/extensions/omni.isaac.lab/omni/isaac/lab/sim/converters/urdf_converter.py

@@ -5,31 +5,17 @@
 
 from __future__ import annotations
 
+import math
+import re
+
 import isaacsim
 import omni.kit.commands
 import omni.usd
 from isaacsim.core.utils.extensions import enable_extension
-from isaacsim.core.version import get_version
-from pxr import Usd
 
 from .asset_converter_base import AssetConverterBase
 from .urdf_converter_cfg import UrdfConverterCfg
 
-_DRIVE_TYPE = {
-    "none": 0,
-    "position": 1,
-    "velocity": 2,
-}
-"""Mapping from drive type name to URDF importer drive number."""
-
-_NORMALS_DIVISION = {
-    "catmullClark": 0,
-    "loop": 1,
-    "bilinear": 2,
-    "none": 3,
-}
-"""Mapping from normals division name to urdf importer normals division number."""
-
 
 class UrdfConverter(AssetConverterBase):
     """Converter for a URDF description file to a USD file.
@@ -47,10 +33,6 @@ class UrdfConverter(AssetConverterBase):
         From Isaac Sim 4.5 onwards, the extension name changed from ``omni.importer.urdf`` to
         ``isaacsim.asset.importer.urdf``. This converter class now uses the latest extension from Isaac Sim.
 
-        The new extension supports a custom XML tag``"dont_collapse"`` for joints. Setting this parameter
-        to true in the URDF joint tag prevents the child link from collapsing when the associated joint type
-        is "fixed".
-
     .. _isaacsim.asset.importer.urdf: https://docs.omniverse.nvidia.com/isaacsim/latest/ext_omni_isaac_urdf.html
     """
 
@@ -63,6 +45,10 @@ class UrdfConverter(AssetConverterBase):
         Args:
             cfg: The configuration instance for URDF to USD conversion.
         """
+        enable_extension("isaacsim.asset.importer.urdf")
+        from isaacsim.asset.importer.urdf._urdf import acquire_urdf_interface
+
+        self._urdf_interface = acquire_urdf_interface()
         super().__init__(cfg=cfg)
 
     """
@@ -75,41 +61,45 @@ class UrdfConverter(AssetConverterBase):
         Args:
             cfg: The URDF conversion configuration.
         """
-        import_config = self._get_urdf_import_config(cfg)
+
+        import_config = self._get_urdf_import_config()
+        # parse URDF file
+        result, self._robot_model = omni.kit.commands.execute(
+            "URDFParseFile", urdf_path=cfg.asset_path, import_config=import_config
+        )
+
+        if result:
+            if cfg.joint_drive:
+                # modify joint parameters
+                self._update_joint_parameters()
+
+            # set root link name
+            if cfg.root_link_name:
+                self._robot_model.root_link = cfg.root_link_name
+
+            # convert the model to USD
             omni.kit.commands.execute(
-            "URDFParseAndImportFile",
+                "URDFImportRobot",
                 urdf_path=cfg.asset_path,
+                urdf_robot=self._robot_model,
                 import_config=import_config,
                 dest_path=self.usd_path,
             )
-
-        # fix the issue that material paths are not relative
-        # note: This issue seems to have popped up in Isaac Sim 2023.1.1
-        stage = Usd.Stage.Open(self.usd_path)
-        # resolve all paths relative to layer path
-        source_layer = stage.GetRootLayer()
-        omni.usd.resolve_paths(source_layer.identifier, source_layer.identifier)
-        stage.Save()
+        else:
+            raise ValueError(f"Failed to parse URDF file: {cfg.asset_path}")
 
     """
     Helper methods.
     """
 
-    def _get_urdf_import_config(self, cfg: UrdfConverterCfg) -> isaacsim.asset.importer.urdf.ImportConfig:
+    def _get_urdf_import_config(self) -> isaacsim.asset.importer.urdf.ImportConfig:
         """Create and fill URDF ImportConfig with desired settings
 
-        Args:
-            cfg: The URDF conversion configuration.
-
         Returns:
             The constructed ``ImportConfig`` object containing the desired settings.
         """
-        # Enable urdf extension
-        enable_extension("isaacsim.asset.importer.urdf")
-
-        from isaacsim.asset.importer.urdf import _urdf as omni_urdf
-
-        import_config = omni_urdf.ImportConfig()
+        # create a new import config
+        _, import_config = omni.kit.commands.execute("URDFCreateImportConfig")
 
         # set the unit scaling factor, 1.0 means meters, 100.0 means cm
         import_config.set_distance_scale(1.0)
@@ -120,29 +110,210 @@ class UrdfConverter(AssetConverterBase):
 
         # -- asset settings
         # default density used for links, use 0 to auto-compute
-        import_config.set_density(cfg.link_density)
-        # import inertia tensor from urdf, if it is not specified in urdf it will import as identity
-        import_config.set_import_inertia_tensor(cfg.import_inertia_tensor)
-        # decompose a convex mesh into smaller pieces for a closer fit
-        import_config.set_convex_decomp(cfg.convex_decompose_mesh)
-        import_config.set_subdivision_scheme(_NORMALS_DIVISION["bilinear"])
-
+        import_config.set_density(self.cfg.link_density)
+        # mesh simplification settings
+        convex_decomp = self.cfg.collider_type == "convex_decomposition"
+        import_config.set_convex_decomp(convex_decomp)
+        # create collision geometry from visual geometry
+        import_config.set_collision_from_visuals(self.cfg.collision_from_visuals)
+        # consolidating links that are connected by fixed joints
+        import_config.set_merge_fixed_joints(self.cfg.merge_fixed_joints)
         # -- physics settings
         # create fix joint for base link
-        import_config.set_fix_base(cfg.fix_base)
-        # consolidating links that are connected by fixed joints
-        import_config.set_merge_fixed_joints(cfg.merge_fixed_joints)
+        import_config.set_fix_base(self.cfg.fix_base)
         # self collisions between links in the articulation
-        import_config.set_self_collision(cfg.self_collision)
-
-        # default drive type used for joints
-        import_config.set_default_drive_type(_DRIVE_TYPE[cfg.default_drive_type])
-        # default proportional gains
-        import_config.set_default_drive_strength(cfg.default_drive_stiffness)
-        # default derivative gains
-        import_config.set_default_position_drive_damping(cfg.default_drive_damping)
-        if get_version()[2] == "4":
-            # override joint dynamics parsed from urdf
-            import_config.set_override_joint_dynamics(cfg.override_joint_dynamics)
+        import_config.set_self_collision(self.cfg.self_collision)
+        # convert mimic joints to normal joints
+        import_config.set_parse_mimic(self.cfg.convert_mimic_joints_to_normal_joints)
+        # replace cylinder shapes with capsule shapes
+        import_config.set_replace_cylinders_with_capsules(self.cfg.replace_cylinders_with_capsules)
 
         return import_config
+
+    def _update_joint_parameters(self):
+        """Update the joint parameters based on the configuration."""
+        # set the drive type
+        self._set_joints_drive_type()
+        # set the drive target type
+        self._set_joints_drive_target_type()
+        # set the drive gains
+        self._set_joint_drive_gains()
+
+    def _set_joints_drive_type(self):
+        """Set the joint drive type for all joints in the URDF model."""
+        from isaacsim.asset.importer.urdf._urdf import UrdfJointDriveType
+
+        drive_type_mapping = {
+            "force": UrdfJointDriveType.JOINT_DRIVE_FORCE,
+            "acceleration": UrdfJointDriveType.JOINT_DRIVE_ACCELERATION,
+        }
+
+        if isinstance(self.cfg.joint_drive.drive_type, str):
+            for joint in self._robot_model.joints.values():
+                joint.drive.set_drive_type(drive_type_mapping[self.cfg.joint_drive.drive_type])
+        elif isinstance(self.cfg.joint_drive.drive_type, dict):
+            for joint_name, drive_type in self.cfg.joint_drive.drive_type.items():
+                # handle joint name being a regex
+                matches = [s for s in self._robot_model.joints.keys() if re.search(joint_name, s)]
+                if not matches:
+                    raise ValueError(
+                        f"The joint name {joint_name} in the drive type config was not found in the URDF file. The"
+                        f" joint names in the URDF are {list(self._robot_model.joints.keys())}"
+                    )
+                for match in matches:
+                    joint = self._robot_model.joints[match]
+                    joint.drive.set_drive_type(drive_type_mapping[drive_type])
+
+    def _set_joints_drive_target_type(self):
+        """Set the joint drive target type for all joints in the URDF model."""
+        from isaacsim.asset.importer.urdf._urdf import UrdfJointTargetType
+
+        target_type_mapping = {
+            "none": UrdfJointTargetType.JOINT_DRIVE_NONE,
+            "position": UrdfJointTargetType.JOINT_DRIVE_POSITION,
+            "velocity": UrdfJointTargetType.JOINT_DRIVE_VELOCITY,
+        }
+
+        if isinstance(self.cfg.joint_drive.target_type, str):
+            for joint in self._robot_model.joints.values():
+                joint.drive.set_target_type(target_type_mapping[self.cfg.joint_drive.target_type])
+        elif isinstance(self.cfg.joint_drive.target_type, dict):
+            for joint_name, target_type in self.cfg.joint_drive.target_type.items():
+                # handle joint name being a regex
+                matches = [s for s in self._robot_model.joints.keys() if re.search(joint_name, s)]
+                if not matches:
+                    raise ValueError(
+                        f"The joint name {joint_name} in the target type config was not found in the URDF file. The"
+                        f" joint names in the URDF are {list(self._robot_model.joints.keys())}"
+                    )
+                for match in matches:
+                    joint = self._robot_model.joints[match]
+                    joint.drive.set_target_type(target_type_mapping[target_type])
+
+    def _set_joint_drive_gains(self):
+        """Set the joint drive gains for all joints in the URDF model."""
+
+        # set the gains directly from stiffness and damping values
+        if isinstance(self.cfg.joint_drive.gains, UrdfConverterCfg.JointDriveCfg.PDGainsCfg):
+            # stiffness
+            if isinstance(self.cfg.joint_drive.gains.stiffness, (float, int)):
+                for joint in self._robot_model.joints.values():
+                    self._set_joint_drive_stiffness(joint, self.cfg.joint_drive.gains.stiffness)
+            elif isinstance(self.cfg.joint_drive.gains.stiffness, dict):
+                for joint_name, stiffness in self.cfg.joint_drive.gains.stiffness.items():
+                    # handle joint name being a regex
+                    matches = [s for s in self._robot_model.joints.keys() if re.search(joint_name, s)]
+                    if not matches:
+                        raise ValueError(
+                            f"The joint name {joint_name} in the drive stiffness config was not found in the URDF file."
+                            f" The joint names in the URDF are {list(self._robot_model.joints.keys())}"
+                        )
+                    for match in matches:
+                        joint = self._robot_model.joints[match]
+                        self._set_joint_drive_stiffness(joint, stiffness)
+            # damping
+            if isinstance(self.cfg.joint_drive.gains.damping, (float, int)):
+                for joint in self._robot_model.joints.values():
+                    self._set_joint_drive_damping(joint, self.cfg.joint_drive.gains.damping)
+            elif isinstance(self.cfg.joint_drive.gains.damping, dict):
+                for joint_name, damping in self.cfg.joint_drive.gains.damping.items():
+                    # handle joint name being a regex
+                    matches = [s for s in self._robot_model.joints.keys() if re.search(joint_name, s)]
+                    if not matches:
+                        raise ValueError(
+                            f"The joint name {joint_name} in the drive damping config was not found in the URDF file."
+                            f" The joint names in the URDF are {list(self._robot_model.joints.keys())}"
+                        )
+                    for match in matches:
+                        joint = self._robot_model.joints[match]
+                        self._set_joint_drive_damping(joint, damping)
+
+        # set the gains from natural frequency and damping ratio
+        elif isinstance(self.cfg.joint_drive.gains, UrdfConverterCfg.JointDriveCfg.NaturalFrequencyGainsCfg):
+            # damping ratio
+            if isinstance(self.cfg.joint_drive.gains.damping_ratio, (float, int)):
+                for joint in self._robot_model.joints.values():
+                    joint.drive.damping_ratio = self.cfg.joint_drive.gains.damping_ratio
+            elif isinstance(self.cfg.joint_drive.gains.damping_ratio, dict):
+                for joint_name, damping_ratio in self.cfg.joint_drive.gains.damping_ratio.items():
+                    # handle joint name being a regex
+                    matches = [s for s in self._robot_model.joints.keys() if re.search(joint_name, s)]
+                    if not matches:
+                        raise ValueError(
+                            f"The joint name {joint_name} in the damping ratio config was not found in the URDF file."
+                            f" The joint names in the URDF are {list(self._robot_model.joints.keys())}"
+                        )
+                    for match in matches:
+                        joint = self._robot_model.joints[match]
+                        joint.drive.damping_ratio = damping_ratio
+
+            # natural frequency (this has to be done after damping ratio is set)
+            if isinstance(self.cfg.joint_drive.gains.natural_frequency, (float, int)):
+                for joint in self._robot_model.joints.values():
+                    joint.drive.natural_frequency = self.cfg.joint_drive.gains.natural_frequency
+                    self._set_joint_drive_gains_from_natural_frequency(joint)
+            elif isinstance(self.cfg.joint_drive.gains.natural_frequency, dict):
+                for joint_name, natural_frequency in self.cfg.joint_drive.gains.natural_frequency.items():
+                    # handle joint name being a regex
+                    matches = [s for s in self._robot_model.joints.keys() if re.search(joint_name, s)]
+                    if not matches:
+                        raise ValueError(
+                            f"The joint name {joint_name} in the natural frequency config was not found in the URDF"
+                            f" file. The joint names in the URDF are {list(self._robot_model.joints.keys())}"
+                        )
+                    for match in matches:
+                        joint = self._robot_model.joints[match]
+                        joint.drive.natural_frequency = natural_frequency
+                        self._set_joint_drive_gains_from_natural_frequency(joint)
+
+    def _set_joint_drive_stiffness(self, joint, stiffness: float):
+        """Set the joint drive stiffness.
+
+        Args:
+            joint: The joint from the URDF robot model.
+            stiffness: The stiffness value.
+        """
+        from isaacsim.asset.importer.urdf._urdf import UrdfJointType
+
+        if joint.type == UrdfJointType.JOINT_PRISMATIC:
+            joint.drive.set_strength(stiffness)
+        else:
+            # we need to convert the stiffness from radians to degrees
+            joint.drive.set_strength(math.pi / 180 * stiffness)
+
+    def _set_joint_drive_damping(self, joint, damping: float):
+        """Set the joint drive damping.
+
+        Args:
+            joint: The joint from the URDF robot model.
+            damping: The damping value.
+        """
+        from isaacsim.asset.importer.urdf._urdf import UrdfJointType
+
+        if joint.type == UrdfJointType.JOINT_PRISMATIC:
+            joint.drive.set_damping(damping)
+        else:
+            # we need to convert the damping from radians to degrees
+            joint.drive.set_damping(math.pi / 180 * damping)
+
+    def _set_joint_drive_gains_from_natural_frequency(self, joint):
+        """Compute the joint drive gains from the natural frequency and damping ratio.
+
+        Args:
+            joint: The joint from the URDF robot model.
+        """
+        from isaacsim.asset.importer.urdf._urdf import UrdfJointDriveType, UrdfJointTargetType
+
+        strength = self._urdf_interface.compute_natural_stiffness(
+            self._robot_model,
+            joint.name,
+            joint.drive.natural_frequency,
+        )
+        self._set_joint_drive_stiffness(joint, strength)
+
+        if joint.drive.target_type == UrdfJointTargetType.JOINT_DRIVE_POSITION:
+            m_eq = 1.0
+            if joint.drive.drive_type == UrdfJointDriveType.JOINT_DRIVE_FORCE:
+                m_eq = joint.inertia
+            damping = 2 * m_eq * joint.drive.natural_frequency * joint.drive.damping_ratio
+            self._set_joint_drive_damping(joint, damping)

source/extensions/omni.isaac.lab/omni/isaac/lab/sim/converters/urdf_converter_cfg.py

@@ -14,50 +14,114 @@ from omni.isaac.lab.utils import configclass
 class UrdfConverterCfg(AssetConverterBaseCfg):
     """The configuration class for UrdfConverter."""
 
-    link_density = 0.0
-    """Default density used for links. Defaults to 0.
+    @configclass
+    class JointDriveCfg:
 
-    This setting is only effective if ``"inertial"`` properties are missing in the URDF.
+        @configclass
+        class PDGainsCfg:
+            """Configuration for the PD gains of the drive."""
+
+            stiffness: dict[str, float] | float = MISSING
+            """The stiffness of the joint drive in Nm/rad or N/rad.
+
+            If None, the stiffness is set to the value parsed from the URDF file.
+            If :attr:`~UrdfConverterCfg.JointDriveCfg.target_type` is set to ``"velocity"``, this value determines
+            the drive strength in joint velocity space.
+            """
+
+            damping: dict[str, float] | float | None = None
+            """The damping of the joint drive in Nm/(rad/s) or N/(rad/s). Defaults to None.
+
+            If None, the damping is set to the value parsed from the URDF file or 0.0 if no value is found in the URDF.
+            If :attr:`~UrdfConverterCfg.JointDriveCfg.target_type` is set to ``"velocity"``, this attribute is set to
+            0.0 and :attr:`stiffness` serves as the drive's strength in joint velocity space.
+            """
+
+        @configclass
+        class NaturalFrequencyGainsCfg:
+            r"""Configuration for the natural frequency gains of the drive.
+
+            Computes the joint drive stiffness and damping based on the desired natural frequency using the formula:
+
+            :math:`P = m \cdot f^2`, :math:`D = 2 \cdot r \cdot f \cdot m`
+
+            where :math:`f` is the natural frequency, :math:`r` is the damping ratio, and :math:`m` is the total
+            equivalent inertia at the joint. The damping ratio is such that:
+
+            * :math:`r = 1.0` is a critically damped system,
+            * :math:`r < 1.0` is underdamped,
+            * :math:`r > 1.0` is overdamped.
+            """
+
+            natural_frequency: dict[str, float] | float = MISSING
+            """The natural frequency of the joint drive.
+
+            If :attr:`~UrdfConverterCfg.JointDriveCfg.target_type` is set to ``"velocity"``, this value determines the
+            drive's natural frequency in joint velocity space.
+            """
+
+            damping_ratio: dict[str, float] | float = 0.005
+            """The damping ratio of the joint drive. Defaults to 0.005.
+
+            If :attr:`~UrdfConverterCfg.JointDriveCfg.target_type` is set to ``"velocity"``, this value is ignored and
+            only :attr:`natural_frequency` is used.
+            """
+
+        drive_type: dict[str, Literal["acceleration", "force"]] | Literal["acceleration", "force"] = "force"
+        """The drive type used for the joint. Defaults to ``"force"``.
+
+        * ``"acceleration"``: The joint drive normalizes the inertia before applying the joint effort so it's invariant
+          to inertia and mass changes (equivalent to ideal damped oscillator).
+        * ``"force"``: Applies effort through forces, so is subject to variations on the body inertia.
         """
 
-    import_inertia_tensor: bool = True
-    """Import the inertia tensor from urdf. Defaults to True.
+        target_type: dict[str, Literal["none", "position", "velocity"]] | Literal["none", "position", "velocity"] = (
+            "position"
+        )
+        """The drive target type used for the joint. Defaults to ``"position"``.
 
-    If the ``"inertial"`` tag is missing, then it is imported as an identity.
+        If the target type is set to ``"none"``, the joint stiffness and damping are set to 0.0.
         """
 
-    convex_decompose_mesh = False
-    """Decompose a convex mesh into smaller pieces for a closer fit. Defaults to False."""
+        gains: PDGainsCfg | NaturalFrequencyGainsCfg = PDGainsCfg()
+        """The drive gains configuration."""
 
     fix_base: bool = MISSING
     """Create a fix joint to the root/base link."""
 
-    merge_fixed_joints: bool = False
-    """Consolidate links that are connected by fixed joints. Defaults to False."""
+    root_link_name: str | None = None
+    """The name of the root link. Defaults to None.
 
-    self_collision: bool = False
-    """Activate self-collisions between links of the articulation. Defaults to False."""
+    If None, the root link will be set by PhysX.
+    """
 
-    default_drive_type: Literal["none", "position", "velocity"] = "none"
-    """The drive type used for joints. Defaults to ``"none"``.
+    link_density: float = 0.0
+    """Default density in ``kg/m^3`` for links whose ``"inertial"`` properties are missing in the URDF. Defaults to 0.0."""
 
-    The drive type dictates the loaded joint PD gains and USD attributes for joint control:
+    merge_fixed_joints: bool = True
+    """Consolidate links that are connected by fixed joints. Defaults to True."""
 
-    * ``"none"``: The joint stiffness and damping are set to 0.0.
-    * ``"position"``: The joint stiff and damping are set based on the URDF file or provided configuration.
-    * ``"velocity"``: The joint stiff is set to zero and damping is based on the URDF file or provided configuration.
-    """
+    convert_mimic_joints_to_normal_joints: bool = False
+    """Convert mimic joints to normal joints. Defaults to False."""
+
+    joint_drive: JointDriveCfg | None = JointDriveCfg()
+    """The joint drive settings.
 
-    override_joint_dynamics: bool = False
-    """Override the joint dynamics parsed from the URDF file. Defaults to False."""
+    None can be used for URDFs without joints.
+    """
 
-    default_drive_stiffness: float = 0.0
-    """The default stiffness of the joint drive. Defaults to 0.0."""
+    collision_from_visuals = False
+    """Create collision geometry from visual geometry."""
 
-    default_drive_damping: float = 0.0
-    """The default damping of the joint drive. Defaults to 0.0.
+    collider_type: Literal["convex_hull", "convex_decomposition"] = "convex_hull"
+    """The collision shape simplification. Defaults to ``"convex_hull"``.
 
-    Note:
-        If ``override_joint_dynamics`` is True, the values parsed from the URDF joint tag ``"<dynamics><damping>"`` are used.
-        Otherwise, it is overridden by the configured value.
+    * ``"convex_hull"``: The collision shape is simplified to a convex hull.
+    * ``"convex_decomposition"``: The collision shape is decomposed into smaller convex shapes for a closer fit.
     """
+
+    self_collision: bool = False
+    """Activate self-collisions between links of the articulation. Defaults to False."""
+
+    replace_cylinders_with_capsules: bool = False
+    """Replace cylinder shapes with capsule shapes. Defaults to False."""

source/extensions/omni.isaac.lab/test/sensors/test_imu.py

@@ -92,6 +92,9 @@ class MySceneCfg(InteractiveSceneCfg):
             articulation_props=sim_utils.ArticulationRootPropertiesCfg(
                 enabled_self_collisions=True, solver_position_iteration_count=4, solver_velocity_iteration_count=0
             ),
+            joint_drive=sim_utils.UrdfConverterCfg.JointDriveCfg(
+                gains=sim_utils.UrdfConverterCfg.JointDriveCfg.PDGainsCfg(stiffness=None, damping=None)
+            ),
         ),
         init_state=ArticulationCfg.InitialStateCfg(),
         actuators={

source/extensions/omni.isaac.lab/test/sim/test_spawn_from_files.py

@@ -74,7 +74,11 @@ class TestSpawningFromFiles(unittest.TestCase):
         extension_path = get_extension_path_from_name("isaacsim.asset.importer.urdf")
         # Spawn franka from URDF
         cfg = sim_utils.UrdfFileCfg(
-            asset_path=f"{extension_path}/data/urdf/robots/franka_description/robots/panda_arm_hand.urdf", fix_base=True
+            asset_path=f"{extension_path}/data/urdf/robots/franka_description/robots/panda_arm_hand.urdf",
+            fix_base=True,
+            joint_drive=sim_utils.UrdfConverterCfg.JointDriveCfg(
+                gains=sim_utils.UrdfConverterCfg.JointDriveCfg.PDGainsCfg(stiffness=None, damping=None)
+            ),
         )
         prim = cfg.func("/World/Franka", cfg)
         # Check validity

source/extensions/omni.isaac.lab/test/sim/test_urdf_converter.py

@@ -13,7 +13,6 @@ simulation_app = AppLauncher(config).app
 
 """Rest everything follows."""
 
-import math
 import numpy as np
 import os
 import unittest
@@ -41,11 +40,16 @@ class TestUrdfConverter(unittest.TestCase):
         self.config = UrdfConverterCfg(
             asset_path=f"{extension_path}/data/urdf/robots/franka_description/robots/panda_arm_hand.urdf",
             fix_base=True,
+            joint_drive=UrdfConverterCfg.JointDriveCfg(
+                gains=UrdfConverterCfg.JointDriveCfg.PDGainsCfg(stiffness=400.0, damping=40.0)
+            ),
         )
         # Simulation time-step
         self.dt = 0.01
         # Load kit helper
-        self.sim = SimulationContext(physics_dt=self.dt, rendering_dt=self.dt, backend="numpy")
+        self.sim = SimulationContext(
+            physics_dt=self.dt, rendering_dt=self.dt, stage_units_in_meters=1.0, backend="numpy"
+        )
 
     def tearDown(self) -> None:
         """Stops simulator after each test."""
@@ -109,10 +113,9 @@ class TestUrdfConverter(unittest.TestCase):
 
         # change the config
         self.config.force_usd_conversion = True
-        self.config.default_drive_type = "position"
-        self.config.default_drive_stiffness = 400.0
-        self.config.default_drive_damping = 40.0
-        self.config.override_joint_dynamics = True
+        self.config.joint_drive.target_type = "position"
+        self.config.joint_drive.gains.stiffness = 42.0
+        self.config.joint_drive.gains.damping = 4.2
         self.config.usd_dir = output_dir
         urdf_converter = UrdfConverter(self.config)
         # check the drive type of the robot
@@ -127,36 +130,14 @@ class TestUrdfConverter(unittest.TestCase):
 
         # check drive values for the robot (read from physx)
         drive_stiffness, drive_damping = robot.get_gains()
-        # -- for the arm (revolute joints)
-        # user provides the values in radians but simulator sets them as in degrees
-        expected_drive_stiffness = math.degrees(self.config.default_drive_stiffness)
-        expected_drive_damping = math.degrees(self.config.default_drive_damping)
-        np.testing.assert_array_equal(drive_stiffness[:, :7], expected_drive_stiffness)
-        np.testing.assert_array_equal(drive_damping[:, :7], expected_drive_damping)
-        # -- for the hand (prismatic joints)
-        # note: from isaac sim 2023.1, the test asset has mimic joints for the hand
-        #  so the mimic joint doesn't have drive values
-        expected_drive_stiffness = self.config.default_drive_stiffness
-        expected_drive_damping = self.config.default_drive_damping
-        np.testing.assert_array_equal(drive_stiffness[:, 7], expected_drive_stiffness)
-        np.testing.assert_array_equal(drive_damping[:, 7], expected_drive_damping)
+        np.testing.assert_array_equal(drive_stiffness, self.config.joint_drive.gains.stiffness)
+        np.testing.assert_array_equal(drive_damping, self.config.joint_drive.gains.damping)
 
         # check drive values for the robot (read from usd)
         self.sim.stop()
         drive_stiffness, drive_damping = robot.get_gains()
-        # -- for the arm (revolute joints)
-        # user provides the values in radians but simulator sets them as in degrees
-        expected_drive_stiffness = math.degrees(self.config.default_drive_stiffness)
-        expected_drive_damping = math.degrees(self.config.default_drive_damping)
-        np.testing.assert_array_equal(drive_stiffness[:, :7], expected_drive_stiffness)
-        np.testing.assert_array_equal(drive_damping[:, :7], expected_drive_damping)
-        # -- for the hand (prismatic joints)
-        # note: from isaac sim 2023.1, the test asset has mimic joints for the hand
-        #  so the mimic joint doesn't have drive values
-        expected_drive_stiffness = self.config.default_drive_stiffness
-        expected_drive_damping = self.config.default_drive_damping
-        np.testing.assert_array_equal(drive_stiffness[:, 7], expected_drive_stiffness)
-        np.testing.assert_array_equal(drive_damping[:, 7], expected_drive_damping)
+        np.testing.assert_array_equal(drive_stiffness, self.config.joint_drive.gains.stiffness)
+        np.testing.assert_array_equal(drive_damping, self.config.joint_drive.gains.damping)
 
 
 if __name__ == "__main__":

source/standalone/tools/convert_urdf.py

@@ -86,6 +86,9 @@ def main():
         fix_base=args_cli.fix_base,
         merge_fixed_joints=args_cli.merge_joints,
         force_usd_conversion=True,
+        joint_drive=UrdfConverterCfg.JointDriveCfg(
+            gains=UrdfConverterCfg.JointDriveCfg.PDGainsCfg(stiffness=100.0, damping=1.0)
+        ),
     )
 
     # Print info

tools/tests_to_skip.py

@@ -11,8 +11,6 @@ TESTS_TO_SKIP = [
     "test_env_var_launch.py",  # app.close issue
     "test_kwarg_launch.py",  # app.close issue
     "test_differential_ik.py",  # Failing
-    "test_urdf_converter.py",  # need to update wrapper for URDF importer
-    "test_mjcf_converter.py",  # need to update wrapper for MJCF importer
     # lab_tasks
     "test_data_collector.py",  # Failing
     "test_record_video.py",  # Failing