[Question] AttributeError: 'RigidObject' object has no attribute '_external_force_b' when spawning Rigid Object on DirectRL Environment. #1142

SantiDiazC · 2024-09-06T06:32:01Z

SantiDiazC
Sep 6, 2024

Hi, I am trying to create an DirectRL environment in which I spawn some robot, gripper and objects for a grasping task. When spawning the robot and gripper I don't have any problem, however, when I tried to add the objects I have the following error:

Traceback (most recent call last):
  File "/home/hri-david/Omniverse/Isaaclab/IsaacLab/Santi_tests/DirectEnv_examples/test_env.py", line 760, in <module>
    main()
  File "/home/hri-david/Omniverse/Isaaclab/IsaacLab/Santi_tests/DirectEnv_examples/test_env.py", line 716, in main
    env.reset()
  File "/home/hri-david/Omniverse/Isaaclab/IsaacLab/source/extensions/omni.isaac.lab/omni/isaac/lab/envs/direct_rl_env.py", line 258, in reset
    self._reset_idx(indices)
  File "/home/hri-david/Omniverse/Isaaclab/IsaacLab/Santi_tests/DirectEnv_examples/test_env.py", line 518, in _reset_idx
    super()._reset_idx(env_ids)
  File "/home/hri-david/Omniverse/Isaaclab/IsaacLab/source/extensions/omni.isaac.lab/omni/isaac/lab/envs/direct_rl_env.py", line 516, in _reset_idx
    self.scene.reset(env_ids)
  File "/home/hri-david/Omniverse/Isaaclab/IsaacLab/source/extensions/omni.isaac.lab/omni/isaac/lab/scene/interactive_scene.py", line 330, in reset
    rigid_object.reset(env_ids)
  File "/home/hri-david/Omniverse/Isaaclab/IsaacLab/source/extensions/omni.isaac.lab/omni/isaac/lab/assets/rigid_object/rigid_object.py", line 100, in reset
    self._external_force_b[env_ids] = 0.0
AttributeError: 'RigidObject' object has no attribute '_external_force_b'

For more context, I set the object configs within the environment config class like this:

@configclass
class MyEnvCfg(DirectRLEnvCfg):
          #         
          #
          #

          cylinder_cfg = RigidObjectCfg(
                      prim_path="/World/envs/env_.*/Cylinder",
                      init_state=RigidObjectCfg.InitialStateCfg(pos=[0.5, 0, 0.055], rot=[1, 0, 0, 0]),
                      spawn=UsdFileCfg(
                          usd_path=f"{ISAAC_NUCLEUS_DIR}/Props/Blocks/DexCube/dex_cube_instanceable.usd",
                          scale=(0.8, 0.8, 0.8),
                          rigid_props=RigidBodyPropertiesCfg(
                              solver_position_iteration_count=16,
                              solver_velocity_iteration_count=1,
                              max_angular_velocity=1000.0,
                              max_linear_velocity=1000.0,
                              max_depenetration_velocity=5.0,
                              disable_gravity=False,
                          ),
                      ),
                  )

and its Spawned inside the env class setup:

class MyEnv(DirectRLEnv):
    # pre-physics step calls
    # 

    cfg: MyEnvCfg

    def _setup_scene(self):
            self._robot = Articulation(self.cfg.robot)
            self._cylinder = RigidObject(self.cfg.cylinder_cfg)
            self.scene.rigid_objects["Cylinder"] = self._cylinder
            self.scene.articulations["Robot"] = self._robot

I don't know if I have to modify the _reset_idx method since is mentioned in the error when the env.reset() is called.
Here it is how I define it (similar to the FrankaCabinetEnv example):

def _reset_idx(self, env_ids: torch.Tensor | None):
        super()._reset_idx(env_ids)
        # robot state
        print("default joint pos: ", self._robot.data.default_joint_pos)
        joint_pos = self._robot.data.default_joint_pos[env_ids] + sample_uniform(
            -0.125,
            0.125,
            (len(env_ids), self._robot.num_joints),
            self.device,
        )
        joint_pos = torch.clamp(joint_pos, self.robot_dof_lower_limits, self.robot_dof_upper_limits)
        joint_vel = torch.zeros_like(joint_pos)
        self._robot.set_joint_position_target(joint_pos, env_ids=env_ids)
        self._robot.write_joint_state_to_sim(joint_pos, joint_vel, env_ids=env_ids)

If there is any solution for this please tell me, thank you!

elle-miller · 2024-09-06T12:30:52Z

elle-miller
Sep 6, 2024

I am getting the same issue with latest IsaacLab release.

Before getting the _external_force_b error, it leads with this error for me. My object config is similar to above.

Traceback (most recent call last):
  File "/home/elle/code/external/IsaacLab/source/extensions/omni.isaac.lab/omni/isaac/lab/assets/asset_base.py", line 92, in <lambda>
    lambda event, obj=weakref.proxy(self): obj._initialize_callback(event),
  File "/home/elle/code/external/IsaacLab/source/extensions/omni.isaac.lab/omni/isaac/lab/assets/asset_base.py", line 263, in _initialize_callback
    self._initialize_impl()
  File "/home/elle/code/external/IsaacLab/source/extensions/omni.isaac.lab/omni/isaac/lab/assets/rigid_object/rigid_object.py", line 280, in _initialize_impl
    raise RuntimeError(
RuntimeError: Failed to find a rigid body when resolving '/World/envs/env_.*/Clutter'. Please ensure that the prim has 'USD RigidBodyAPI' applied.

I also modified the reset function to reset the object position but that doesn't make a difference.

box_default_state = self.box.data.default_root_state.clone()[env_ids]
self.box.write_root_state_to_sim(box_default_state, env_ids)

0 replies

jtigue-bdai · 2024-09-06T20:02:27Z

jtigue-bdai
Sep 6, 2024
Collaborator

@SantiDiazC can you please provide a reproduction script of this error

0 replies

jtigue-bdai · 2024-09-06T20:14:02Z

jtigue-bdai
Sep 6, 2024
Collaborator

Just comparing your configuration of the RigidObject to the ShadoHandEnvCfg

I see that you are not setting mass properties in the spawner. This may be preventing the rigid object from being created completly.

mass_props=sim_utils.MassPropertiesCfg(density=567.0),

 @configclass
class MyEnvCfg(DirectRLEnvCfg):
          #         
          #
          #

          cylinder_cfg = RigidObjectCfg(
                      prim_path="/World/envs/env_.*/Cylinder",
                      init_state=RigidObjectCfg.InitialStateCfg(pos=[0.5, 0, 0.055], rot=[1, 0, 0, 0]),
                      spawn=UsdFileCfg(
                          usd_path=f"{ISAAC_NUCLEUS_DIR}/Props/Blocks/DexCube/dex_cube_instanceable.usd",
                          scale=(0.8, 0.8, 0.8),
                          rigid_props=RigidBodyPropertiesCfg(
                              solver_position_iteration_count=16,
                              solver_velocity_iteration_count=1,
                              max_angular_velocity=1000.0,
                              max_linear_velocity=1000.0,
                              max_depenetration_velocity=5.0,
                              disable_gravity=False,
                          ),
                          mass_props=sim_utils.MassPropertiesCfg(density=567.0),
                      ),
                  )

0 replies

elle-miller · 2024-09-09T09:55:03Z

elle-miller
Sep 9, 2024

Hi @jtigue-bdai ,

For me, the error comes trying to add the table of the manager-based Franka Lift environment to my own DirectRL version.

IsaacLab/source/extensions/omni.isaac.lab_tasks/omni/isaac/lab_tasks/manager_based/manipulation/lift/lift_env_cfg.py

Line 49 in af088f5

    
           spawn=UsdFileCfg(usd_path=f"{ISAAC_NUCLEUS_DIR}/Props/Mounts/SeattleLabTable/table_instanceable.usd"),

My table config is

table_cfg: RigidObjectCfg = RigidObjectCfg(
            prim_path="/World/envs/env_.*/Table",
            init_state=RigidObjectCfg.InitialStateCfg(pos=[0.5, 0, 0], rot=[0.707, 0, 0, 0.707]),
            spawn=UsdFileCfg(usd_path=f"{ISAAC_NUCLEUS_DIR}/Props/Mounts/SeattleLabTable/table_instanceable.usd",
            rigid_props=RigidBodyPropertiesCfg(
                    solver_position_iteration_count=16,
                    solver_velocity_iteration_count=1,
                    max_angular_velocity=1000.0,
                    max_linear_velocity=1000.0,
                    max_depenetration_velocity=5.0,
                    disable_gravity=False,
                ),
        # mass_props=sim_utils.MassPropertiesCfg(density=567.0)
        )
    )

and I instantiate the table as:

def _setup_scene(self):
         .....
        self.table = RigidObject(self.cfg.table_cfg)
        self.scene.rigid_objects["table"] = self.table

I've just noticed an additional error with this setup which probably indicates the problem - can you help decipher this message?

2024-09-09 09:41:27 [11,814ms] [Warning] [omni.isaac.lab.sim.utils] Could not perform 'modify_rigid_body_properties' on any prims under: '/World/envs/env_0/Table'. This might be because of the following reasons:
    (1) The desired attribute does not exist on any of the prims.
    (2) The desired attribute exists on an instanced prim.
        Discovered list of instanced prim paths: ['/World/envs/env_0/Table/Visuals', '/World/envs/env_0/Table/Collisions']

When I add the mass_props you suggested, the above error prints out with the below appended

2024-09-09 09:43:13 [11,591ms] [Warning] [omni.isaac.lab.sim.utils] Could not perform 'modify_mass_properties' on any prims under: '/World/envs/env_0/Table'. This might be because of the following reasons:
    (1) The desired attribute does not exist on any of the prims.
    (2) The desired attribute exists on an instanced prim.
        Discovered list of instanced prim paths: ['/World/envs/env_0/Table/Visuals', '/World/envs/env_0/Table/Collisions']

Thanks in advance!

0 replies

SantiDiazC · 2024-09-19T08:33:00Z

SantiDiazC
Sep 19, 2024
Author

Hi,
I have the same issue described here:

I am getting the same issue with latest IsaacLab release.

Before getting the _external_force_b error, it leads with this error for me. My object config is similar to above.

Traceback (most recent call last):
  File "/home/elle/code/external/IsaacLab/source/extensions/omni.isaac.lab/omni/isaac/lab/assets/asset_base.py", line 92, in <lambda>
    lambda event, obj=weakref.proxy(self): obj._initialize_callback(event),
  File "/home/elle/code/external/IsaacLab/source/extensions/omni.isaac.lab/omni/isaac/lab/assets/asset_base.py", line 263, in _initialize_callback
    self._initialize_impl()
  File "/home/elle/code/external/IsaacLab/source/extensions/omni.isaac.lab/omni/isaac/lab/assets/rigid_object/rigid_object.py", line 280, in _initialize_impl
    raise RuntimeError(
RuntimeError: Failed to find a rigid body when resolving '/World/envs/env_.*/Clutter'. Please ensure that the prim has 'USD RigidBodyAPI' applied.

I also modified the reset function to reset the object position but that doesn't make a difference.

box_default_state = self.box.data.default_root_state.clone()[env_ids]
self.box.write_root_state_to_sim(box_default_state, env_ids)

Before the object was not created on the scene and I got the AttributeError: 'RigidObject' object has no attribute '_external_force_b', but after modifying the code on the _setup_scene method by commenting one line :

def _setup_scene(self):
            self._robot = Articulation(self.cfg.robot)
            self._cylinder = RigidObject(self.cfg.cylinder_cfg)
            self.scene.rigid_objects["Cylinder"] = self._cylinder
            self.scene.articulations["Robot"] = self._robot

to:

def _setup_scene(self):
            self._robot = Articulation(self.cfg.robot)
            self._cylinder = RigidObject(self.cfg.cylinder_cfg)
            # self.scene.rigid_objects["Cylinder"] = self._cylinder
            self.scene.articulations["Robot"] = self._robot

Also when I reset the object on the reset method (reset_id) I get the following error:

cylinder_default_state = self._cylinder.data.default_root_state.clone()[env_ids]
  File "/home/hri-david/Omniverse/Isaaclab/IsaacLab/source/extensions/omni.isaac.lab/omni/isaac/lab/assets/rigid_object/rigid_object.py", line 65, in data
    return self._data
AttributeError: 'RigidObject' object has no attribute '_data'. Did you mean: 'data'?

Thank you in advance!

0 replies

jtigue-bdai · 2024-09-19T19:00:20Z

jtigue-bdai
Sep 19, 2024
Collaborator

@SantiDiazC and @elle-miller because you are using the DirectRLEnv workflow I cannot recreate your issue without your whole DirectRLEnv and Cfg. Please provide a your DirectRLEnv and DirectRLEnvCfg. So that we can recreate your issue.

0 replies

elle-miller · 2024-09-23T12:40:57Z

elle-miller
Sep 23, 2024

Hi @jtigue-bdai of course, here is a "bare bones" version that reproduces the error for me when training with default skrl train.py script. You will need to register the environment etc. Let me know if you need me to provide the full set of files 👍


from __future__ import annotations

import torch
from collections.abc import Sequence

from omni.isaac.lab.assets import (
    RigidObject,
    RigidObjectCfg,
)
from omni.isaac.lab.envs import DirectRLEnv, DirectRLEnvCfg, ViewerCfg
from omni.isaac.lab.scene import InteractiveSceneCfg
from omni.isaac.lab.sim import SimulationCfg
from omni.isaac.lab.sim.schemas.schemas_cfg import RigidBodyPropertiesCfg
from omni.isaac.lab.sim.spawners.from_files import GroundPlaneCfg, spawn_ground_plane
from omni.isaac.lab.sim.spawners.from_files.from_files_cfg import UsdFileCfg
from omni.isaac.lab.utils import configclass
from omni.isaac.lab.utils.assets import ISAAC_NUCLEUS_DIR

@configclass
class LiftEnvCfg(DirectRLEnvCfg):
    physics_dt = 0.01  # 100 Hz
    decimation = 2
    render_interval = 2
    episode_length_s = 5.0  # 5 * 120 / 2 = 300 timesteps

    num_observations = 0
    num_actions = 9
    num_states = 0

    # simulation
    sim: SimulationCfg = SimulationCfg(dt=physics_dt, render_interval=decimation)
    scene: InteractiveSceneCfg = InteractiveSceneCfg(num_envs=4096, env_spacing=2.5, replicate_physics=True)
    viewer: ViewerCfg = ViewerCfg(eye=(1.75, 1.75, 3.0), lookat=(0.0, 0.0, 1.5))

    # in-hand object
    object_cfg: RigidObjectCfg = RigidObjectCfg(
        prim_path="/World/envs/env_.*/Object",
        init_state=RigidObjectCfg.InitialStateCfg(pos=[0.5, 0, 0.055], rot=[1, 0, 0, 0]),
        spawn=UsdFileCfg(
            usd_path=f"{ISAAC_NUCLEUS_DIR}/Props/Blocks/DexCube/dex_cube_instanceable.usd",
            scale=(0.8, 0.8, 0.8),
            rigid_props=RigidBodyPropertiesCfg(
                solver_position_iteration_count=16,
                solver_velocity_iteration_count=1,
                max_angular_velocity=1000.0,
                max_linear_velocity=1000.0,
                max_depenetration_velocity=5.0,
                disable_gravity=False,
            ),
        ),
    )

    table_cfg: RigidObjectCfg = RigidObjectCfg(
        prim_path="/World/envs/env_.*/Table",
        init_state=RigidObjectCfg.InitialStateCfg(pos=[0.5, 0, 0], rot=[0.707, 0, 0, 0.707]),
        spawn=UsdFileCfg(
            usd_path=f"{ISAAC_NUCLEUS_DIR}/Props/Mounts/SeattleLabTable/table_instanceable.usd",
            rigid_props=RigidBodyPropertiesCfg(
                solver_position_iteration_count=16,
                solver_velocity_iteration_count=1,
                max_angular_velocity=1000.0,
                max_linear_velocity=1000.0,
                max_depenetration_velocity=5.0,
                disable_gravity=False,
            ),
            # mass_props=sim_utils.MassPropertiesCfg(density=567.0)
        ),
    )


class LiftEnv(DirectRLEnv):
    # pre-physics step calls
    #   |-- _pre_physics_step(action)
    #   |-- _apply_action()
    # post-physics step calls
    #   |-- _get_dones()
    #   |-- _get_rewards()
    #   |-- _reset_idx(env_ids)
    #   |-- _get_observations()

    cfg: LiftEnvCfg

    def __init__(self, cfg: LiftEnvCfg, render_mode: str | None = None, **kwargs):
        super().__init__(cfg, render_mode, **kwargs)
        self.random_vector = torch.zeros((self.num_envs, 1)) 

    def _setup_scene(self):

        self.object = RigidObject(self.cfg.object_cfg)

        # Issues with this particular rigid object
        self.table = RigidObject(self.cfg.table_cfg)

        # add ground plane
        spawn_ground_plane(prim_path="/World/ground", cfg=GroundPlaneCfg())

        # clone and replicate (no need to filter for this environment)
        self.scene.clone_environments(copy_from_source=False)

        self.scene.rigid_objects["object"] = self.object
        self.scene.rigid_objects["table"] = self.table

    def _pre_physics_step(self, actions: torch.Tensor) -> None:
        self.last_action = self.robot_dof_targets[:, self.actuated_dof_indices]
        self.actions = actions.clone()

    def _apply_action(self) -> None:
        self.robot.set_joint_position_target(
            self.robot_dof_targets[:, self.actuated_dof_indices], joint_ids=self.actuated_dof_indices
        )

    def _get_observations(self) -> dict:
        obs = self.random_vector
        return obs

    def _get_rewards(self) -> torch.Tensor:
        rewards = self.random_vector
        return rewards

    def _get_dones(self) -> tuple[torch.Tensor, torch.Tensor]:
        termination = self.random_vector
        time_out = self.random_vector
        return termination, time_out

    def _reset_idx(self, env_ids: Sequence[int] | None):
        if env_ids is None:
            env_ids = self.robot._ALL_INDICES
        super()._reset_idx(env_ids)

        # reset table (ISSUES! SO REMOVING FOR NOW)
        table_state = self.table.data.default_root_state.clone()[env_ids]
        self.table.write_root_state_to_sim(table_state, env_ids)

1 reply

SantiDiazC Oct 16, 2024
Author

Hi @elle-miller,
If you still have about resetting the rigid object in the scene, a solution to this is in: Isaaclab/source/standalone/demos/multi_asset.py example.

def _reset_idx(self, env_ids: Sequence[int] | None):
        if env_ids is None:
            env_ids = self.robot._ALL_INDICES
        super()._reset_idx(env_ids)
        
        # reset box
        box_default_state = self._box.data.default_root_state.clone()[env_ids] 
        box_default_state[:, :3] += self.scene.env_origins
        self._box.write_root_state_to_sim(box_default_state, env_ids=env_ids)

I think there should be a better solution or maybe this functionality can be added into the RigidObject class but I am not sure.

Dhoeller19 · 2024-10-04T14:54:13Z

Dhoeller19
Oct 4, 2024

Hi @SantiDiazC and @elle-miller,
The reason you are seeing this problem is that your USD file you try to load doesn't contain any Physics Rigid body.
As an example for the table, you have to create a new USD that contains a rigid body:

Open Isaac Sim and open the table USD (http://omniverse-content-production.s3-us-west-2.amazonaws.com/Assets/Isaac/4.2/Isaac/Props/Mounts/SeattleLabTable/table_instanceable.usd)
Save a local copy (File -> Save as)
Right click on Collisions and do Add -> Physics -> Rigid Body
Save the file and load this one instead in your script.

1 reply

elle-miller Dec 4, 2024

Hi @Dhoeller19 , I just tried this but still no luck. This is what the collisions look like for my local table_instanceable.usd after I've added the rigid body.

TerenceXue-tech · 2024-11-13T10:17:25Z

TerenceXue-tech
Nov 13, 2024

This is most likely an issue with the USD file. You need to set the default_prim_path to your rigidobject.

1 reply

shaoxiang Dec 17, 2024

Yes, I solved the problem through this answer. I forgot to set my rigidbody to default_prim.

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[Question] AttributeError: 'RigidObject' object has no attribute '_external_force_b' when spawning Rigid Object on DirectRL Environment. #1142

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[Question] AttributeError: 'RigidObject' object has no attribute '_external_force_b' when spawning Rigid Object on DirectRL Environment. #1142

Replies: 9 comments · 3 replies

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