API

Python API

manipulators

SingleManipulator

Provides high level functions to set/ get properties and actions of a manipulator with a single end effector and optionally a gripper.

controllers

PickPlaceController	A simple pick and place state machine for tutorials
StackingController	[summary]

grippers

Gripper	Provides high level functions to set/ get properties and actions of a gripper.
ParallelGripper	Provides high level functions to set/ get properties and actions of a parllel gripper (a gripper that has two fingers).
SurfaceGripper	Provides high level functions to set/ get properties and actions of a surface gripper (a suction cup for example).

Manipulators

class SingleManipulator(

prim_path: str,

end_effector_prim_name: str | None = None,

end_effector_prim_path: str | None = None,

name: str = 'single_manipulator',

position: Sequence[float] | None = None,

translation: Sequence[float] | None = None,

orientation: Sequence[float] | None = None,

scale: Sequence[float] | None = None,

visible: bool | None = None,

gripper: Gripper | None = None,

)

Bases: SingleArticulation

Provides high level functions to set/ get properties and actions of a manipulator with a single end effector and optionally a gripper.

Parameters:

• prim_path (str) – prim path of the Prim to encapsulate or create.

• end_effector_prim_name (str) – end effector prim name to be used to track the rigid body that corresponds to the end effector. One of the following args can be specified only: end_effector_prim_name or end_effector_prim_path.

• end_effector_prim_path (str) – end effector prim path to be used to track the rigid body that corresponds to the end effector. One of the following args can be specified only: end_effector_prim_name or end_effector_prim_path.

• name (str, optional) – shortname to be used as a key by Scene class. Note: needs to be unique if the object is added to the Scene. Defaults to “single_manipulator”.

• position (Optional[Sequence[float]], optional) – position in the world frame of the prim. shape is (3, ). Defaults to None, which means left unchanged.

• translation (Optional[Sequence[float]], optional) – translation in the local frame of the prim (with respect to its parent prim). shape is (3, ). Defaults to None, which means left unchanged.

• orientation (Optional[Sequence[float]], optional) – quaternion orientation in the world/ local frame of the prim (depends if translation or position is specified). quaternion is scalar-first (w, x, y, z). shape is (4, ). Defaults to None, which means left unchanged.

• scale (Optional[Sequence[float]], optional) – local scale to be applied to the prim’s dimensions. shape is (3, ). Defaults to None, which means left unchanged.

• visible (Optional[bool], optional) – set to false for an invisible prim in the stage while rendering. Defaults to True.

• gripper (Gripper, optional) – Gripper to be used with the manipulator. Defaults to None.

property end_effector: SingleRigidPrim

Returns: SingleRigidPrim: end effector of the manipulator (can be used to get its world pose, angular velocity..etc).

property gripper: Gripper

Returns: Gripper: gripper of the manipulator (can be used to open or close the gripper, get its world pose or angular velocity..etc).

initialize(

physics_sim_view: omni.physics.tensors.SimulationView | None = None,

) → None

Create a physics simulation view if not passed and creates an articulation view using physX tensor api.

This needs to be called after each hard reset (i.e stop + play on the timeline) before interacting with any of the functions of this class.

Parameters:

physics_sim_view (omni.physics.tensors.SimulationView, optional) – current physics simulation view. Defaults to None.

post_reset() → None

Resets the manipulator, the end effector and the gripper to its default state.

apply_action(

control_actions: ArticulationAction,

) → None

Apply joint positions, velocities and/or efforts to control an articulation

Parameters:

• control_actions (ArticulationAction) – actions to be applied for next physics step.

• indices (Optional[Union[list, np.ndarray]], optional) – degree of freedom indices to apply actions to. Defaults to all degrees of freedom.

Hint

High stiffness makes the joints snap faster and harder to the desired target, and higher damping smoothes but also slows down the joint’s movement to target

• For position control, set relatively high stiffness and low damping (to reduce vibrations)

• For velocity control, stiffness must be set to zero with a non-zero damping

• For effort control, stiffness and damping must be set to zero

Example:

>>> from isaacsim.core.utils.types import ArticulationAction
>>>
>>> # move all the robot joints to the indicated position
>>> action = ArticulationAction(joint_positions=np.array([0.0, -1.0, 0.0, -2.2, 0.0, 2.4, 0.8, 0.04, 0.04]))
>>> prim.apply_action(action)
>>>
>>> # close the robot fingers: panda_finger_joint1 (7) and panda_finger_joint2 (8) to 0.0
>>> action = ArticulationAction(joint_positions=np.array([0.0, 0.0]), joint_indices=np.array([7, 8]))
>>> prim.apply_action(action)

apply_visual_material(

visual_material: VisualMaterial,

weaker_than_descendants: bool = False,

) → None

Apply visual material to the held prim and optionally its descendants.

Parameters:

• visual_material (VisualMaterial) – visual material to be applied to the held prim. Currently supports PreviewSurface, OmniPBR and OmniGlass.

• weaker_than_descendants (bool, optional) – True if the material shouldn’t override the descendants materials, otherwise False. Defaults to False.

Example:

>>> from isaacsim.core.api.materials import OmniGlass
>>>
>>> # create a dark-red glass visual material
>>> material = OmniGlass(
...     prim_path="/World/material/glass",  # path to the material prim to create
...     ior=1.25,
...     depth=0.001,
...     thin_walled=False,
...     color=np.array([0.5, 0.0, 0.0])
... )
>>> prim.apply_visual_material(material)

disable_gravity() → None

Keep gravity from affecting the robot

Example:

>>> prim.disable_gravity()

property dof_names: List[str]

List of prim names for each DOF.

Returns:

prim names

Return type:

list(string)

Example:

>>> prim.dof_names
['panda_joint1', 'panda_joint2', 'panda_joint3', 'panda_joint4', 'panda_joint5',
 'panda_joint6', 'panda_joint7', 'panda_finger_joint1', 'panda_finger_joint2']

property dof_properties: ndarray

Articulation DOF properties

DOF properties

Index	Property name	Description
0	type	DOF type: invalid/unknown/uninitialized (0), rotation (1), translation (2)
1	hasLimits	Whether the DOF has limits
2	lower	Lower DOF limit (in radians or meters)
3	upper	Upper DOF limit (in radians or meters)
4	driveMode	Drive mode for the DOF: force (1), acceleration (2)
5	maxVelocity	Maximum DOF velocity. In radians/s, or stage_units/s
6	maxEffort	Maximum DOF effort. In N or N*stage_units
7	stiffness	DOF stiffness
8	damping	DOF damping

Returns:

named NumPy array of shape (num_dof, 9)

Return type:

np.ndarray

Example:

>>> # get properties for all DOFs
>>> prim.dof_properties
[(1,  True, -2.8973,  2.8973, 1, 1.0000000e+01, 5220., 60000., 3000.)
 (1,  True, -1.7628,  1.7628, 1, 1.0000000e+01, 5220., 60000., 3000.)
 (1,  True, -2.8973,  2.8973, 1, 5.9390470e+36, 5220., 60000., 3000.)
 (1,  True, -3.0718, -0.0698, 1, 5.9390470e+36, 5220., 60000., 3000.)
 (1,  True, -2.8973,  2.8973, 1, 5.9390470e+36,  720., 25000., 3000.)
 (1,  True, -0.0175,  3.7525, 1, 5.9390470e+36,  720., 15000., 3000.)
 (1,  True, -2.8973,  2.8973, 1, 1.0000000e+01,  720.,  5000., 3000.)
 (2,  True,  0.    ,  0.04  , 1, 3.4028235e+38,  720.,  6000., 1000.)
 (2,  True,  0.    ,  0.04  , 1, 3.4028235e+38,  720.,  6000., 1000.)]
>>>
>>> # property names
>>> prim.dof_properties.dtype.names
('type', 'hasLimits', 'lower', 'upper', 'driveMode', 'maxVelocity', 'maxEffort', 'stiffness', 'damping')
>>>
>>> # get DOF upper limits
>>> prim.dof_properties["upper"]
[ 2.8973  1.7628  2.8973 -0.0698  2.8973  3.7525  2.8973  0.04    0.04  ]
>>>
>>> # get the last DOF (panda_finger_joint2) upper limit
>>> prim.dof_properties["upper"][8]  # or prim.dof_properties[8][3]
0.04

enable_gravity() → None

Gravity will affect the robot

Example:

>>> prim.enable_gravity()

get_angular_velocity() → ndarray

Get the angular velocity of the root articulation prim

Returns:

3D angular velocity vector. Shape (3,)

Return type:

np.ndarray

Example:

>>> prim.get_angular_velocity()
[0. 0. 0.]

get_applied_action() → ArticulationAction

Get the last applied action

Returns:

last applied action. Note: a dictionary is used as the object’s string representation

Return type:

ArticulationAction

Example:

>>> # last applied action: joint_positions -> [0.0, -1.0, 0.0, -2.2, 0.0, 2.4, 0.8, 0.04, 0.04]
>>> prim.get_applied_action()
{'joint_positions': [0.0, -1.0, 0.0, -2.200000047683716, 0.0, 2.4000000953674316,
                     0.800000011920929, 0.03999999910593033, 0.03999999910593033],
 'joint_velocities': [0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0],
 'joint_efforts': [0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0]}

get_applied_joint_efforts(

joint_indices: List | ndarray | None = None,

) → ndarray

Get the efforts applied to the joints set by the set_joint_efforts method

Parameters:

joint_indices (Optional[Union[List, np.ndarray]], optional) – indices to specify which joints to read. Defaults to None (all joints)

Raises:

Exception – If the handlers are not initialized

Returns:

all or selected articulation joint applied efforts

Return type:

np.ndarray

Example:

>>> # get all applied joint efforts
>>> prim.get_applied_joint_efforts()
[ 0.  0.  0.  0.  0.  0.  0.  0.  0.]
>>>
>>> # get finger applied efforts: panda_finger_joint1 (7) and panda_finger_joint2 (8)
>>> prim.get_applied_joint_efforts(joint_indices=np.array([7, 8]))
[0.  0.]

get_applied_visual_material() → VisualMaterial

Return the current applied visual material in case it was applied using apply_visual_material or it’s one of the following materials that was already applied before: PreviewSurface, OmniPBR and OmniGlass.

Returns:

the current applied visual material if its type is currently supported.

Return type:

VisualMaterial

Example:

>>> # given a visual material applied
>>> prim.get_applied_visual_material()
<isaacsim.core.api.materials.omni_glass.OmniGlass object at 0x7f36263106a0>

get_articulation_body_count() → int

Get the number of bodies (links) that make up the articulation

Returns:

amount of bodies

Return type:

int

Example:

>>> prim.get_articulation_body_count()
12

get_articulation_controller() → ArticulationController

Get the articulation controller

Note

If no articulation_controller was passed during class instantiation, a default controller of type ArticulationController (a Proportional-Derivative controller that can apply position targets, velocity targets and efforts) will be used

Returns:

articulation controller

Return type:

ArticulationController

Example:

>>> prim.get_articulation_controller()
<isaacsim.core.api.controllers.articulation_controller.ArticulationController object at 0x7f04a0060190>

get_default_state() → XFormPrimState

Get the default prim states (spatial position and orientation).

Returns:

an object that contains the default state of the prim (position and orientation)

Return type:

XFormPrimState

Example:

>>> state = prim.get_default_state()
>>> state
<isaacsim.core.utils.types.XFormPrimState object at 0x7f33addda650>
>>>
>>> state.position
[-4.5299529e-08 -1.8347054e-09 -2.8610229e-08]
>>> state.orientation
[1. 0. 0. 0.]

get_dof_index(dof_name: str) → int

Get a DOF index given its name

Parameters:

dof_name (str) – name of the DOF

Returns:

DOF index

Return type:

int

Example:

>>> prim.get_dof_index("panda_finger_joint2")
8

get_enabled_self_collisions() → int

Get the enable self collisions flag (physxArticulation:enabledSelfCollisions)

Returns:

self collisions flag (boolean interpreted as int)

Return type:

int

Example:

>>> prim.get_enabled_self_collisions()
0

get_joint_positions(

joint_indices: List | ndarray | None = None,

) → ndarray

Get the articulation joint positions

Parameters:

joint_indices (Optional[Union[List, np.ndarray]], optional) – indices to specify which joints to read. Defaults to None (all joints)

Returns:

all or selected articulation joint positions

Return type:

np.ndarray

Example:

>>> # get all joint positions
>>> prim.get_joint_positions()
[ 1.1999920e-02 -5.6962633e-01  1.3480479e-08 -2.8105433e+00  6.8284894e-06
  3.0301569e+00  7.3234749e-01  3.9912373e-02  3.9999999e-02]
>>>
>>> # get finger positions: panda_finger_joint1 (7) and panda_finger_joint2 (8)
>>> prim.get_joint_positions(joint_indices=np.array([7, 8]))
[0.03991237  3.9999999e-02]

get_joint_velocities(

joint_indices: List | ndarray | None = None,

) → ndarray

Get the articulation joint velocities

Parameters:

joint_indices (Optional[Union[List, np.ndarray]], optional) – indices to specify which joints to read. Defaults to None (all joints)

Returns:

all or selected articulation joint velocities

Return type:

np.ndarray

Example:

>>> # get all joint velocities
>>> prim.get_joint_velocities()
[ 1.91603772e-06 -7.67638255e-03 -2.19138826e-07  1.10636465e-02 -4.63412944e-05
  3.48245539e-02  8.84692147e-02  5.40335372e-04 1.02849208e-05]
>>>
>>> # get finger velocities: panda_finger_joint1 (7) and panda_finger_joint2 (8)
>>> prim.get_joint_velocities(joint_indices=np.array([7, 8]))
[5.4033537e-04 1.0284921e-05]

get_joints_default_state() → JointsState

Get the default joint states (positions and velocities).

Returns:

an object that contains the default joint positions and velocities

Return type:

JointsState

Example:

>>> state = prim.get_joints_default_state()
>>> state
<isaacsim.core.utils.types.JointsState object at 0x7f04a0061240>
>>>
>>> state.positions
[ 0.012  -0.57000005  0.  -2.81  0.  3.037  0.785398  0.04  0.04 ]
>>> state.velocities
[0. 0. 0. 0. 0. 0. 0. 0. 0.]

get_joints_state() → JointsState

Get the current joint states (positions and velocities)

Returns:

an object that contains the current joint positions and velocities

Return type:

JointsState

Example:

>>> state = prim.get_joints_state()
>>> state
<isaacsim.core.utils.types.JointsState object at 0x7f02f6df57b0>
>>>
>>> state.positions
[ 1.1999920e-02 -5.6962633e-01  1.3480479e-08 -2.8105433e+00 6.8284894e-06
  3.0301569e+00  7.3234749e-01  3.9912373e-02  3.9999999e-02]
>>> state.velocities
[ 1.91603772e-06 -7.67638255e-03 -2.19138826e-07  1.10636465e-02 -4.63412944e-05
  245539e-02  8.84692147e-02  5.40335372e-04  1.02849208e-05]

get_linear_velocity() → ndarray

Get the linear velocity of the root articulation prim

Returns:

3D linear velocity vector. Shape (3,)

Return type:

np.ndarray

Example:

>>> prim.get_linear_velocity()
[0. 0. 0.]

get_local_pose() → Tuple[ndarray, ndarray]

Get prim’s pose with respect to the local frame (the prim’s parent frame)

Returns:

first index is the position in the local frame (with shape (3, )). Second index is quaternion orientation (with shape (4, )) in the local frame

Return type:

Tuple[np.ndarray, np.ndarray]

Example:

>>> # if the prim is in position (1.0, 0.5, 0.0) with respect to the world frame
>>> position, orientation = prim.get_local_pose()
>>> position
[0. 0. 0.]
>>> orientation
[0. 0. 0.]

get_local_scale() → ndarray

Get prim’s scale with respect to the local frame (the parent’s frame)

Returns:

scale applied to the prim’s dimensions in the local frame. shape is (3, ).

Return type:

np.ndarray

Example:

>>> prim.get_local_scale()
[1. 1. 1.]

get_measured_joint_efforts(

joint_indices: List | ndarray | None = None,

) → ndarray

Returns the efforts computed/measured by the physics solver of the joint forces in the DOF motion direction

Parameters:

joint_indices (Optional[Union[List, np.ndarray]], optional) – indices to specify which joints to read. Defaults to None (all joints)

Raises:

Exception – If the handlers are not initialized

Returns:

all or selected articulation joint measured efforts

Return type:

np.ndarray

Example:

>>> # get all joint efforts
>>> prim.get_measured_joint_efforts()
[ 2.7897308e-06 -6.9083519e+00 -3.6398471e-06  1.9158335e+01 -4.3552645e-06
  1.1866090e+00 -4.7079347e-06  3.2339853e-04 -3.2044132e-04]
>>>
>>> # get finger efforts: panda_finger_joint1 (7) and panda_finger_joint2 (8)
>>> prim.get_measured_joint_efforts(joint_indices=np.array([7, 8]))
[ 0.0003234  -0.00032044]

get_measured_joint_forces(

joint_indices: List | ndarray | None = None,

) → ndarray

Get the measured joint reaction forces and torques (link incoming joint forces and torques) to external loads

Note

Since the name->index map for joints has not been exposed yet, it is possible to access the joint names and their indices through the articulation metadata.

prim._articulation_view._metadata.joint_names  # list of names
prim._articulation_view._metadata.joint_indices  # dict of name: index

To retrieve a specific row for the link incoming joint force/torque use joint_index + 1

Parameters:

joint_indices (Optional[Union[List, np.ndarray]], optional) – indices to specify which joints to read. Defaults to None (all joints)

Raises:

Exception – If the handlers are not initialized

Returns:

measured joint forces and torques. Shape is (num_joint + 1, 6). Row index 0 is the incoming joint of the base link. For the last dimension the first 3 values are for forces and the last 3 for torques

Return type:

np.ndarray

Example:

>>> # get all measured joint forces and torques
>>> prim.get_measured_joint_forces()
[[ 0.0000000e+00  0.0000000e+00  0.0000000e+00  0.0000000e+00  0.0000000e+00  0.0000000e+00]
 [ 1.4995076e+02  4.2574748e-06  5.6364370e-04  4.8701895e-05 -6.9072924e+00  3.1881387e-05]
 [-2.8971717e-05 -1.0677823e+02 -6.8384506e+01 -6.9072924e+00 -5.4927128e-05  6.1222494e-07]
 [ 8.7120995e+01 -4.3871860e-05 -5.5795174e+01  5.3687054e-05 -2.4538563e+01  1.3333466e-05]
 [ 5.3519474e-05 -4.8109909e+01  6.0709282e+01  1.9157074e+01 -5.9258469e-05  8.2744418e-07]
 [-3.1691040e+01  2.3313689e-04  3.9990173e+01 -5.8968733e-05 -1.1863431e+00  2.2335558e-05]
 [-1.0809851e-04  1.5340537e+01 -1.5458489e+01  1.1863426e+00  6.1094368e-05 -1.5940281e-05]
 [-7.5418940e+00 -5.0814648e+00 -5.6512990e+00 -5.6385466e-05  3.8859999e-01 -3.4943256e-01]
 [ 4.7421460e+00 -3.1945827e+00  3.5528181e+00  5.5852943e-05  8.4794536e-03  7.6405057e-03]
 [ 4.0760727e+00  2.1640673e-01 -4.0513167e+00 -5.9565349e-04  1.1407082e-02  2.1432268e-06]
 [ 5.1680198e-03 -9.7754575e-02 -9.7093947e-02 -8.4155556e-12 -1.2910691e-12 -1.9347857e-11]
 [-5.1910793e-03  9.7588278e-02 -9.7106412e-02  8.4155573e-12  1.2910637e-12 -1.9347855e-11]]
>>>
>>> # get measured joint force and torque for the fingers
>>> metadata = prim._articulation_view._metadata
>>> joint_indices = 1 + np.array([
...     metadata.joint_indices["panda_finger_joint1"],
...     metadata.joint_indices["panda_finger_joint2"],
... ])
>>> joint_indices
[10 11]
>>> prim.get_measured_joint_forces(joint_indices)
[[ 5.1680198e-03 -9.7754575e-02 -9.7093947e-02 -8.4155556e-12 -1.2910691e-12 -1.9347857e-11]
 [-5.1910793e-03  9.7588278e-02 -9.7106412e-02  8.4155573e-12  1.2910637e-12 -1.9347855e-11]]

get_position_residual(

report_max: bool | None = True,

) → float

Get physics solver position residuals for articulations. This is the residual across all joints that are part of articulations.

The solver residuals are computed according to impulse variation normalized by the effective mass.

Parameters:

report_max (Optional[bool]) – whether to report max or RMS residual. Defaults to True, i.e. max criteria

Returns:

solver position/velocity max/rms residual.

Return type:

float

get_sleep_threshold() → float

Get the threshold for articulations to enter a sleep state

Search for Articulations and Sleeping in PhysX docs for more details

Returns:

sleep threshold

Return type:

float

Example:

>>> prim.get_sleep_threshold()
0.005

get_solver_position_iteration_count() → int

Get the solver (position) iteration count for the articulation

The solver iteration count determines how accurately contacts, drives, and limits are resolved. Search for Solver Iteration Count in PhysX docs for more details.

Returns:

position iteration count

Return type:

int

Example:

>>> prim.get_solver_position_iteration_count()
32

get_solver_velocity_iteration_count() → int

Get the solver (velocity) iteration count for the articulation

The solver iteration count determines how accurately contacts, drives, and limits are resolved. Search for Solver Iteration Count in PhysX docs for more details.

Returns:

velocity iteration count

Return type:

int

Example:

>>> prim.get_solver_velocity_iteration_count()
32

get_stabilization_threshold() → float

Get the mass-normalized kinetic energy below which the articulation may participate in stabilization

Search for Stabilization Threshold in PhysX docs for more details

Returns:

stabilization threshold

Return type:

float

Example:

>>> prim.get_stabilization_threshold()
0.0009999999

get_velocity_residual(

report_max: bool | None = True,

) → float

Get physics solver velocity residuals for articulations. This is the residual across all joints that are part of articulations.

The solver residuals are computed according to impulse variation normalized by the effective mass.

Parameters:

report_max (Optional[bool]) – whether to report max or RMS residual. Defaults to True, i.e. max criteria

Returns:

solver velocity max/rms residual.

Return type:

float

get_visibility() → bool

Returns:

true if the prim is visible in stage. false otherwise.

Return type:

bool

Example:

>>> # get the visible state of an visible prim on the stage
>>> prim.get_visibility()
True

get_world_pose() → Tuple[ndarray, ndarray]

Get prim’s pose with respect to the world’s frame

Returns:

first index is the position in the world frame (with shape (3, )). Second index is quaternion orientation (with shape (4, )) in the world frame

Return type:

Tuple[np.ndarray, np.ndarray]

Example:

>>> # if the prim is in position (1.0, 0.5, 0.0) with respect to the world frame
>>> position, orientation = prim.get_world_pose()
>>> position
[1.  0.5 0. ]
>>> orientation
[1. 0. 0. 0.]

get_world_scale() → ndarray

Get prim’s scale with respect to the world’s frame

Returns:

scale applied to the prim’s dimensions in the world frame. shape is (3, ).

Return type:

np.ndarray

Example:

>>> prim.get_world_scale()
[1. 1. 1.]

get_world_velocity() → ndarray

Get the articulation root velocity

Returns:

current velocity of the the root prim. Shape (3,).

Return type:

np.ndarray

property handles_initialized: bool

Check if articulation handler is initialized

Returns:

whether the handler was initialized

Return type:

bool

Example:

>>> prim.handles_initialized
True

is_valid() → bool

Check if the prim path has a valid USD Prim at it

Returns:

True is the current prim path corresponds to a valid prim in stage. False otherwise.

Return type:

bool

Example:

>>> # given an existing and valid prim
>>> prims.is_valid()
True

is_visual_material_applied() → bool

Check if there is a visual material applied

Returns:

True if there is a visual material applied. False otherwise.

Return type:

bool

Example:

>>> # given a visual material applied
>>> prim.is_visual_material_applied()
True

property name: str | None

Returns: str: name given to the prim when instantiating it. Otherwise None.

property non_root_articulation_link: bool

Used to query if the prim is a non root articulation link

Returns:

True if the prim itself is a non root link

Return type:

bool

Example:

>>> # for a wrapped articulation (where the root prim has the Physics Articulation Root property applied)
>>> prim.non_root_articulation_link
False

property num_bodies: int

Number of articulation links

Returns:

number of links

Return type:

int

Example:

>>> prim.num_bodies
9

property num_dof: int

Number of DOF of the articulation

Returns:

amount of DOFs

Return type:

int

Example:

>>> prim.num_dof
9

property prim: pxr.Usd.Prim

Returns: Usd.Prim: USD Prim object that this object holds.

property prim_path: str

Returns: str: prim path in the stage

set_angular_velocity(

velocity: ndarray,

) → None

Set the angular velocity of the root articulation prim

Warning

This method will immediately set the articulation state

Parameters:

velocity (np.ndarray) – 3D angular velocity vector. Shape (3,)

Hint

This method belongs to the methods used to set the articulation kinematic state:

set_linear_velocity, set_angular_velocity, set_joint_positions, set_joint_velocities, set_joint_efforts

Example:

>>> prim.set_angular_velocity(np.array([0.1, 0.0, 0.0]))

set_default_state(

position: Sequence[float] | None = None,

orientation: Sequence[float] | None = None,

) → None

Set the default state of the prim (position and orientation), that will be used after each reset.

Parameters:

• position (Optional[Sequence[float]], optional) – position in the world frame of the prim. shape is (3, ). Defaults to None, which means left unchanged.

• orientation (Optional[Sequence[float]], optional) – quaternion orientation in the world frame of the prim. quaternion is scalar-first (w, x, y, z). shape is (4, ). Defaults to None, which means left unchanged.

Example:

>>> # configure default state
>>> prim.set_default_state(position=np.array([1.0, 0.5, 0.0]), orientation=np.array([1, 0, 0, 0]))
>>>
>>> # set default states during post-reset
>>> prim.post_reset()

set_enabled_self_collisions(flag: bool) → None

Set the enable self collisions flag (physxArticulation:enabledSelfCollisions)

Parameters:

flag (bool) – whether to enable self collisions

Example:

>>> prim.set_enabled_self_collisions(True)

set_joint_efforts(

efforts: ndarray,

joint_indices: List | ndarray | None = None,

) → None

Set the articulation joint efforts

Note

This method can be used for effort control. For this purpose, there must be no joint drive or the stiffness and damping must be set to zero.

Parameters:

• efforts (np.ndarray) – articulation joint efforts

• joint_indices (Optional[Union[list, np.ndarray]], optional) – indices to specify which joints to manipulate. Defaults to None (all joints)

Hint

This method belongs to the methods used to set the articulation kinematic state:

set_linear_velocity, set_angular_velocity, set_joint_positions, set_joint_velocities, set_joint_efforts

Example:

>>> # set all the robot joint efforts to 0.0
>>> prim.set_joint_efforts(np.array([0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0]))
>>>
>>> # set only the fingers efforts: panda_finger_joint1 (7) and panda_finger_joint2 (8) to 10
>>> prim.set_joint_efforts(np.array([10, 10]), joint_indices=np.array([7, 8]))

set_joint_positions(

positions: ndarray,

joint_indices: List | ndarray | None = None,

) → None

Set the articulation joint positions

Warning

This method will immediately set (teleport) the affected joints to the indicated value. Use the apply_action method to control robot joints.

Parameters:

• positions (np.ndarray) – articulation joint positions

• joint_indices (Optional[Union[list, np.ndarray]], optional) – indices to specify which joints to manipulate. Defaults to None (all joints)

Hint

This method belongs to the methods used to set the articulation kinematic state:

set_linear_velocity, set_angular_velocity, set_joint_positions, set_joint_velocities, set_joint_efforts

Example:

>>> # set all the robot joints
>>> prim.set_joint_positions(np.array([0.0, -1.0, 0.0, -2.2, 0.0, 2.4, 0.8, 0.04, 0.04]))
>>>
>>> # set only the fingers in closed position: panda_finger_joint1 (7) and panda_finger_joint2 (8) to 0.0
>>> prim.set_joint_positions(np.array([0.04, 0.04]), joint_indices=np.array([7, 8]))

set_joint_velocities(

velocities: ndarray,

joint_indices: List | ndarray | None = None,

) → None

Set the articulation joint velocities

Warning

This method will immediately set the affected joints to the indicated value. Use the apply_action method to control robot joints.

Parameters:

• velocities (np.ndarray) – articulation joint velocities

• joint_indices (Optional[Union[list, np.ndarray]], optional) – indices to specify which joints to manipulate. Defaults to None (all joints)

Hint

This method belongs to the methods used to set the articulation kinematic state:

set_linear_velocity, set_angular_velocity, set_joint_positions, set_joint_velocities, set_joint_efforts

Example:

>>> # set all the robot joint velocities to 0.0
>>> prim.set_joint_velocities(np.array([0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0]))
>>>
>>> # set only the fingers velocities: panda_finger_joint1 (7) and panda_finger_joint2 (8) to -0.01
>>> prim.set_joint_velocities(np.array([-0.01, -0.01]), joint_indices=np.array([7, 8]))

set_joints_default_state(

positions: ndarray | None = None,

velocities: ndarray | None = None,

efforts: ndarray | None = None,

) → None

Set the joint default states (positions, velocities and/or efforts) to be applied after each reset.

Note

The default states will be set during post-reset (e.g., calling .post_reset() or world.reset() methods)

Parameters:

• positions (Optional[np.ndarray], optional) – joint positions. Defaults to None.

• velocities (Optional[np.ndarray], optional) – joint velocities. Defaults to None.

• efforts (Optional[np.ndarray], optional) – joint efforts. Defaults to None.

Example:

>>> # configure default joint states
>>> prim.set_joints_default_state(
...     positions=np.array([0.0, -1.0, 0.0, -2.2, 0.0, 2.4, 0.8, 0.04, 0.04]),
...     velocities=np.zeros(shape=(prim.num_dof,)),
...     efforts=np.zeros(shape=(prim.num_dof,))
... )
>>>
>>> # set default states during post-reset
>>> prim.post_reset()

set_linear_velocity(

velocity: ndarray,

) → None

Set the linear velocity of the root articulation prim

Warning

This method will immediately set the articulation state

Parameters:

velocity (np.ndarray) – 3D linear velocity vector. Shape (3,).

Hint

This method belongs to the methods used to set the articulation kinematic state:

set_linear_velocity, set_angular_velocity, set_joint_positions, set_joint_velocities, set_joint_efforts

Example:

>>> prim.set_linear_velocity(np.array([0.1, 0.0, 0.0]))

set_local_pose(

translation: Sequence[float] | None = None,

orientation: Sequence[float] | None = None,

) → None

Set prim’s pose with respect to the local frame (the prim’s parent frame).

Warning

This method will change (teleport) the prim pose immediately to the indicated value

Parameters:

• translation (Optional[Sequence[float]], optional) – translation in the local frame of the prim (with respect to its parent prim). shape is (3, ). Defaults to None, which means left unchanged.

• orientation (Optional[Sequence[float]], optional) – quaternion orientation in the local frame of the prim. quaternion is scalar-first (w, x, y, z). shape is (4, ). Defaults to None, which means left unchanged.

Hint

This method belongs to the methods used to set the prim state

Example:

>>> prim.set_local_pose(translation=np.array([1.0, 0.5, 0.0]), orientation=np.array([1., 0., 0., 0.]))

set_local_scale(

scale: Sequence[float] | None,

) → None

Set prim’s scale with respect to the local frame (the prim’s parent frame).

Parameters:

scale (Optional[Sequence[float]]) – scale to be applied to the prim’s dimensions. shape is (3, ). Defaults to None, which means left unchanged.

Example:

>>> # scale prim 10 times smaller
>>> prim.set_local_scale(np.array([0.1, 0.1, 0.1]))

set_sleep_threshold(threshold: float) → None

Set the threshold for articulations to enter a sleep state

Search for Articulations and Sleeping in PhysX docs for more details

Parameters:

threshold (float) – sleep threshold

Example:

>>> prim.set_sleep_threshold(0.01)

set_solver_position_iteration_count(

count: int,

) → None

Set the solver (position) iteration count for the articulation

The solver iteration count determines how accurately contacts, drives, and limits are resolved. Search for Solver Iteration Count in PhysX docs for more details.

Warning

Setting a higher number of iterations may improve the fidelity of the simulation, although it may affect its performance.

Parameters:

count (int) – position iteration count

Example:

>>> prim.set_solver_position_iteration_count(64)

set_solver_velocity_iteration_count(count: int)

Set the solver (velocity) iteration count for the articulation

The solver iteration count determines how accurately contacts, drives, and limits are resolved. Search for Solver Iteration Count in PhysX docs for more details.

Warning

Setting a higher number of iterations may improve the fidelity of the simulation, although it may affect its performance.

Parameters:

count (int) – velocity iteration count

Example:

>>> prim.set_solver_velocity_iteration_count(64)

set_stabilization_threshold(

threshold: float,

) → None

Set the mass-normalized kinetic energy below which the articulation may participate in stabilization

Search for Stabilization Threshold in PhysX docs for more details

Parameters:

threshold (float) – stabilization threshold

Example:

>>> prim.set_stabilization_threshold(0.005)

set_visibility(visible: bool) → None

Set the visibility of the prim in stage

Parameters:

visible (bool) – flag to set the visibility of the usd prim in stage.

Example:

>>> # make prim not visible in the stage
>>> prim.set_visibility(visible=False)

set_world_pose(

position: Sequence[float] | None = None,

orientation: Sequence[float] | None = None,

) → None

Ses prim’s pose with respect to the world’s frame

Warning

This method will change (teleport) the prim pose immediately to the indicated value

Parameters:

• position (Optional[Sequence[float]], optional) – position in the world frame of the prim. shape is (3, ). Defaults to None, which means left unchanged.

• orientation (Optional[Sequence[float]], optional) – quaternion orientation in the world frame of the prim. quaternion is scalar-first (w, x, y, z). shape is (4, ). Defaults to None, which means left unchanged.

Hint

This method belongs to the methods used to set the prim state

Example:

>>> prim.set_world_pose(position=np.array([1.0, 0.5, 0.0]), orientation=np.array([1., 0., 0., 0.]))

set_world_velocity(velocity: ndarray)

Set the articulation root velocity

Parameters:

velocity (np.ndarray) – linear and angular velocity to set the root prim to. Shape (6,).

Controllers

class PickPlaceController(

name: str,

cspace_controller: BaseController,

gripper: Gripper,

end_effector_initial_height: float | None = None,

events_dt: List[float] | None = None,

)

Bases: BaseController

A simple pick and place state machine for tutorials

Each phase runs for 1 second, which is the internal time of the state machine

Dt of each phase/ event step is defined

• Phase 0: Move end_effector above the cube center at the ‘end_effector_initial_height’.

• Phase 1: Lower end_effector down to encircle the target cube

• Phase 2: Wait for Robot’s inertia to settle.

• Phase 3: close grip.

• Phase 4: Move end_effector up again, keeping the grip tight (lifting the block).

• Phase 5: Smoothly move the end_effector toward the goal xy, keeping the height constant.

• Phase 6: Move end_effector vertically toward goal height at the ‘end_effector_initial_height’.

• Phase 7: loosen the grip.

• Phase 8: Move end_effector vertically up again at the ‘end_effector_initial_height’

• Phase 9: Move end_effector towards the old xy position.

Parameters:

• name (str) – Name id of the controller

• cspace_controller (BaseController) – a cartesian space controller that returns an ArticulationAction type

• gripper (Gripper) – a gripper controller for open/ close actions.

• end_effector_initial_height (Optional[float], optional) – end effector initial picking height to start from (more info in phases above). If not defined, set to 0.3 meters. Defaults to None.

• events_dt (Optional[List[float]], optional) – Dt of each phase/ event step. 10 phases dt has to be defined. Defaults to None.

Raises:

• Exception – events dt need to be list or numpy array

• Exception – events dt need have length of 10

is_paused() → bool

Returns:

True if the state machine is paused. Otherwise False.

Return type:

bool

get_current_event() → int

Returns:

Current event/ phase of the state machine

Return type:

int

forward(

picking_position: ndarray,

placing_position: ndarray,

current_joint_positions: ndarray,

end_effector_offset: ndarray | None = None,

end_effector_orientation: ndarray | None = None,

) → ArticulationAction

Runs the controller one step.

Parameters:

• picking_position (np.ndarray) – The object’s position to be picked in local frame.

• placing_position (np.ndarray) – The object’s position to be placed in local frame.

• current_joint_positions (np.ndarray) – Current joint positions of the robot.

• end_effector_offset (Optional[np.ndarray], optional) – offset of the end effector target. Defaults to None.

• end_effector_orientation (Optional[np.ndarray], optional) – end effector orientation while picking and placing. Defaults to None.

Returns:

action to be executed by the ArticulationController

Return type:

ArticulationAction

reset(

end_effector_initial_height: float | None = None,

events_dt: List[float] | None = None,

) → None

Resets the state machine to start from the first phase/ event

Parameters:

• end_effector_initial_height (Optional[float], optional) – end effector initial picking height to start from. If not defined, set to 0.3 meters. Defaults to None.

• events_dt (Optional[List[float]], optional) – Dt of each phase/ event step. 10 phases dt has to be defined. Defaults to None.

Raises:

• Exception – events dt need to be list or numpy array

• Exception – events dt need have length of 10

is_done() → bool

Returns:

True if the state machine reached the last phase. Otherwise False.

Return type:

bool

pause() → None

Pauses the state machine’s time and phase.

resume() → None

Resumes the state machine’s time and phase.

class StackingController(

name: str,

pick_place_controller: PickPlaceController,

picking_order_cube_names: List[str],

robot_observation_name: str,

)

Bases: BaseController

[summary]

Parameters:

• name (str) – [description]

• pick_place_controller (PickPlaceController) – [description]

• picking_order_cube_names (List[str]) – [description]

• robot_observation_name (str) – [description]

forward(

observations: dict,

end_effector_orientation: ndarray | None = None,

end_effector_offset: ndarray | None = None,

) → ArticulationAction

A controller should take inputs and returns an ArticulationAction to be then passed to the

ArticulationController.

Parameters:

observations (dict) – [description]

Raises:

NotImplementedError – [description]

Returns:

[description]

Return type:

ArticulationAction

reset(

picking_order_cube_names: List[str] | None = None,

) → None

[summary]

Parameters:

picking_order_cube_names (Optional[List[str]], optional) – [description]. Defaults to None.

is_done() → bool

[summary]

Returns:

[description]

Return type:

bool

Grippers

class Gripper(end_effector_prim_path: str)

Bases: SingleRigidPrim

Provides high level functions to set/ get properties and actions of a gripper.

Parameters:

end_effector_prim_path (str) – prim path of the Prim that corresponds to the gripper root/ end effector.

initialize(

physics_sim_view: omni.physics.tensors.SimulationView | None = None,

) → None

Create a physics simulation view if not passed and creates a rigid prim view using physX tensor api.

This needs to be called after each hard reset (i.e stop + play on the timeline) before interacting with any of the functions of this class.

Parameters:

physics_sim_view (omni.physics.tensors.SimulationView, optional) – current physics simulation view. Defaults to None.

abstract open() → None

Applies actions to the articulation that opens the gripper (ex: to release an object held).

abstract close() → None

Applies actions to the articulation that closes the gripper (ex: to hold an object).

abstract set_default_state(*args, **kwargs)

Sets the default state of the gripper

abstract get_default_state(*args, **kwargs)

Gets the default state of the gripper

abstract forward(

*args,

**kwargs,

) → ArticulationAction

calculates the ArticulationAction for all of the articulation joints that corresponds to a specific action

such as “open” for an example.

Returns:

articulation action to be passed to the articulation itself

(includes all joints of the articulation).

Return type:

ArticulationAction

apply_visual_material(

visual_material: VisualMaterial,

weaker_than_descendants: bool = False,

) → None

Apply visual material to the held prim and optionally its descendants.

Parameters:

• visual_material (VisualMaterial) – visual material to be applied to the held prim. Currently supports PreviewSurface, OmniPBR and OmniGlass.

• weaker_than_descendants (bool, optional) – True if the material shouldn’t override the descendants materials, otherwise False. Defaults to False.

Example:

>>> from isaacsim.core.api.materials import OmniGlass
>>>
>>> # create a dark-red glass visual material
>>> material = OmniGlass(
...     prim_path="/World/material/glass",  # path to the material prim to create
...     ior=1.25,
...     depth=0.001,
...     thin_walled=False,
...     color=np.array([0.5, 0.0, 0.0])
... )
>>> prim.apply_visual_material(material)

disable_rigid_body_physics() → None

Disable the rigid body physics

When disabled, the object will not be moved by external forces such as gravity and collisions

Example:

>>> prim.disable_rigid_body_physics()

enable_rigid_body_physics() → None

Enable the rigid body physics

When enabled, the object will be moved by external forces such as gravity and collisions

Example:

>>> prim.enable_rigid_body_physics()

get_angular_velocity()

Get the angular velocity of the rigid body

Returns:

current angular velocity of the the rigid prim. Shape (3,).

Return type:

np.ndarray

get_applied_visual_material() → VisualMaterial

Return the current applied visual material in case it was applied using apply_visual_material or it’s one of the following materials that was already applied before: PreviewSurface, OmniPBR and OmniGlass.

Returns:

the current applied visual material if its type is currently supported.

Return type:

VisualMaterial

Example:

>>> # given a visual material applied
>>> prim.get_applied_visual_material()
<isaacsim.core.api.materials.omni_glass.OmniGlass object at 0x7f36263106a0>

get_com() → float

Get the center of mass pose of the rigid body

Returns:

position of the center of mass of the rigid body. np.ndarray: orientation of the center of mass of the rigid body.

Return type:

np.ndarray

get_current_dynamic_state() → DynamicState

Get the current rigid body state (position, orientation and linear and angular velocities)

Returns:

the dynamic state of the rigid body prim

Return type:

DynamicState

Example:

>>> # for the example the rigid body is in free fall
>>> state = prim.get_current_dynamic_state()
>>> state
<isaacsim.core.utils.types.DynamicState object at 0x7f740b36f670>
>>> state.position
[  0.99999857   2.0000017  -74.2862    ]
>>> state.orientation
[ 1.0000000e+00 -2.3961178e-07 -4.9891562e-09  4.9388258e-09]
>>> state.linear_velocity
[  0.        0.      -38.09554]
>>> state.angular_velocity
[0. 0. 0.]

get_density() → float

Get the density of the rigid body

Returns:

density of the rigid body.

Return type:

float

Example:

>>> prim.get_density()
0

get_linear_velocity() → ndarray

Get the linear velocity of the rigid body

Returns:

current linear velocity of the the rigid prim. Shape (3,).

Return type:

np.ndarray

Example:

>>> prim.get_linear_velocity()
[ 1.0812164e-04  6.1415871e-05 -2.1341663e-04]

get_local_pose() → Tuple[ndarray, ndarray]

Get prim’s pose with respect to the local frame (the prim’s parent frame)

Returns:

first index is the position in the local frame (with shape (3, )). Second index is quaternion orientation (with shape (4, )) in the local frame

Return type:

Tuple[np.ndarray, np.ndarray]

Example:

>>> # if the prim is in position (1.0, 0.5, 0.0) with respect to the world frame
>>> position, orientation = prim.get_local_pose()
>>> position
[0. 0. 0.]
>>> orientation
[0. 0. 0.]

get_local_scale() → ndarray

Get prim’s scale with respect to the local frame (the parent’s frame)

Returns:

scale applied to the prim’s dimensions in the local frame. shape is (3, ).

Return type:

np.ndarray

Example:

>>> prim.get_local_scale()
[1. 1. 1.]

get_mass() → float

Get the mass of the rigid body

Returns:

mass of the rigid body in kg.

Return type:

float

Example:

>>> prim.get_mass()
0

get_sleep_threshold() → float

Get the threshold for the rigid body to enter a sleep state

Search for Rigid Body Dynamics > Sleeping in PhysX docs for more details

Returns:

Mass-normalized kinetic energy threshold below which

an actor may go to sleep. Range: [0, inf) Defaults: 0.00005 * tolerancesSpeed* tolerancesSpeed Units: distance^2 / second^2.

Return type:

float

Example:

>>> prim.get_sleep_threshold()
5e-05

get_visibility() → bool

Returns:

true if the prim is visible in stage. false otherwise.

Return type:

bool

Example:

>>> # get the visible state of an visible prim on the stage
>>> prim.get_visibility()
True

get_world_pose() → Tuple[ndarray, ndarray]

Get prim’s pose with respect to the world’s frame

Returns:

first index is the position in the world frame (with shape (3, )). Second index is quaternion orientation (with shape (4, )) in the world frame

Return type:

Tuple[np.ndarray, np.ndarray]

Example:

>>> # if the prim is in position (1.0, 0.5, 0.0) with respect to the world frame
>>> position, orientation = prim.get_world_pose()
>>> position
[1.  0.5 0. ]
>>> orientation
[1. 0. 0. 0.]

get_world_scale() → ndarray

Get prim’s scale with respect to the world’s frame

Returns:

scale applied to the prim’s dimensions in the world frame. shape is (3, ).

Return type:

np.ndarray

Example:

>>> prim.get_world_scale()
[1. 1. 1.]

is_valid() → bool

Check if the prim path has a valid USD Prim at it

Returns:

True is the current prim path corresponds to a valid prim in stage. False otherwise.

Return type:

bool

Example:

>>> # given an existing and valid prim
>>> prims.is_valid()
True

is_visual_material_applied() → bool

Check if there is a visual material applied

Returns:

True if there is a visual material applied. False otherwise.

Return type:

bool

Example:

>>> # given a visual material applied
>>> prim.is_visual_material_applied()
True

property name: str | None

Returns: str: name given to the prim when instantiating it. Otherwise None.

property non_root_articulation_link: bool

Used to query if the prim is a non root articulation link

Returns:

True if the prim itself is a non root link

Return type:

bool

Example:

>>> # for a wrapped articulation (where the root prim has the Physics Articulation Root property applied)
>>> prim.non_root_articulation_link
False

post_reset() → None

Reset the prim to its default state (position and orientation).

Note

For an articulation, in addition to configuring the root prim’s default position and spatial orientation (defined via the set_default_state method), the joint’s positions, velocities, and efforts (defined via the set_joints_default_state method) are imposed

Example:

>>> prim.post_reset()

property prim: pxr.Usd.Prim

Returns: Usd.Prim: USD Prim object that this object holds.

property prim_path: str

Returns: str: prim path in the stage

set_angular_velocity(velocity: ndarray) → None

Set the angular velocity of the rigid body in stage

Warning

This method will immediately set the articulation state

Parameters:

velocity (np.ndarray) – angular velocity to set the rigid prim to. Shape (3,).

set_com(

position: ndarray,

orientation: ndarray,

) → None

Set the center of mass pose of the rigid body

Parameters:

• position (np.ndarray) – center of mass position. Shape (3,).

• orientation (np.ndarray) – center of mass orientation. Shape (4,).

set_density(density: float) → None

Set the density of the rigid body

Parameters:

mass (float) – density of the rigid body.

Example:

>>> prim.set_density(0.9)

set_linear_velocity(velocity: ndarray)

Set the linear velocity of the rigid body in stage

Warning

This method will immediately set the rigid prim state

Parameters:

velocity (np.ndarray) – linear velocity to set the rigid prim to. Shape (3,).

set_local_pose(

translation: Sequence[float] | None = None,

orientation: Sequence[float] | None = None,

) → None

Set prim’s pose with respect to the local frame (the prim’s parent frame).

Warning

This method will change (teleport) the prim pose immediately to the indicated value

Parameters:

• translation (Optional[Sequence[float]], optional) – translation in the local frame of the prim (with respect to its parent prim). shape is (3, ). Defaults to None, which means left unchanged.

• orientation (Optional[Sequence[float]], optional) – quaternion orientation in the local frame of the prim. quaternion is scalar-first (w, x, y, z). shape is (4, ). Defaults to None, which means left unchanged.

Hint

This method belongs to the methods used to set the prim state

Example:

>>> prim.set_local_pose(translation=np.array([1.0, 0.5, 0.0]), orientation=np.array([1., 0., 0., 0.]))

set_local_scale(scale: Sequence[float] | None) → None

Set prim’s scale with respect to the local frame (the prim’s parent frame).

Parameters:

scale (Optional[Sequence[float]]) – scale to be applied to the prim’s dimensions. shape is (3, ). Defaults to None, which means left unchanged.

Example:

>>> # scale prim 10 times smaller
>>> prim.set_local_scale(np.array([0.1, 0.1, 0.1]))

set_mass(mass: float) → None

Set the mass of the rigid body

Parameters:

mass (float) – mass of the rigid body in kg.

Example:

>>> prim.set_mass(1.0)

set_sleep_threshold(threshold: float) → None

Set the threshold for the rigid body to enter a sleep state

Search for Rigid Body Dynamics > Sleeping in PhysX docs for more details

Parameters:

threshold (float) – Mass-normalized kinetic energy threshold below which an actor may go to sleep. Range: [0, inf) Defaults: 0.00005 * tolerancesSpeed* tolerancesSpeed Units: distance^2 / second^2.

Example:

>>> prim.set_sleep_threshold(1e-5)

set_visibility(visible: bool) → None

Set the visibility of the prim in stage

Parameters:

visible (bool) – flag to set the visibility of the usd prim in stage.

Example:

>>> # make prim not visible in the stage
>>> prim.set_visibility(visible=False)

set_world_pose(

position: Sequence[float] | None = None,

orientation: Sequence[float] | None = None,

) → None

Ses prim’s pose with respect to the world’s frame

Warning

This method will change (teleport) the prim pose immediately to the indicated value

Parameters:

• position (Optional[Sequence[float]], optional) – position in the world frame of the prim. shape is (3, ). Defaults to None, which means left unchanged.

• orientation (Optional[Sequence[float]], optional) – quaternion orientation in the world frame of the prim. quaternion is scalar-first (w, x, y, z). shape is (4, ). Defaults to None, which means left unchanged.

Hint

This method belongs to the methods used to set the prim state

Example:

>>> prim.set_world_pose(position=np.array([1.0, 0.5, 0.0]), orientation=np.array([1., 0., 0., 0.]))

class ParallelGripper(

end_effector_prim_path: str,

joint_prim_names: List[str],

joint_opened_positions: ndarray,

joint_closed_positions: ndarray,

action_deltas: ndarray | None = None,

)

Bases: Gripper

Provides high level functions to set/ get properties and actions of a parllel gripper (a gripper that has two fingers).

Parameters:

• end_effector_prim_path (str) – prim path of the Prim that corresponds to the gripper root/ end effector.

• joint_prim_names (List[str]) – the left finger joint prim name and the right finger joint prim name respectively.

• joint_opened_positions (np.ndarray) – joint positions of the left finger joint and the right finger joint respectively when opened.

• joint_closed_positions (np.ndarray) – joint positions of the left finger joint and the right finger joint respectively when closed.

• action_deltas (np.ndarray, optional) – deltas to apply for finger joint positions when openning or closing the gripper. Defaults to None.

property joint_opened_positions: ndarray

Returns: np.ndarray: joint positions of the left finger joint and the right finger joint respectively when opened.

property joint_closed_positions: ndarray

Returns: np.ndarray: joint positions of the left finger joint and the right finger joint respectively when closed.

property joint_dof_indicies: ndarray

Returns: np.ndarray: joint dof indices in the articulation of the left finger joint and the right finger joint respectively.

property joint_prim_names: List[str]

Returns: List[str]: the left finger joint prim name and the right finger joint prim name respectively.

initialize(

articulation_apply_action_func: Callable,

get_joint_positions_func: Callable,

set_joint_positions_func: Callable,

dof_names: List,

physics_sim_view: omni.physics.tensors.SimulationView | None = None,

) → None

Create a physics simulation view if not passed and creates a rigid prim view using physX tensor api.

This needs to be called after each hard reset (i.e stop + play on the timeline) before interacting with any of the functions of this class.

Parameters:

• articulation_apply_action_func (Callable) – apply_action function from the Articulation class.

• get_joint_positions_func (Callable) – get_joint_positions function from the Articulation class.

• set_joint_positions_func (Callable) – set_joint_positions function from the Articulation class.

• dof_names (List) – dof names from the Articulation class.

• physics_sim_view (omni.physics.tensors.SimulationView, optional) – current physics simulation view. Defaults to None

Raises:

Exception – _description_

open() → None

Applies actions to the articulation that opens the gripper (ex: to release an object held).

close() → None

Applies actions to the articulation that closes the gripper (ex: to hold an object).

set_action_deltas(value: ndarray) → None

Parameters:

value (np.ndarray) – deltas to apply for finger joint positions when openning or closing the gripper. [left, right]. Defaults to None.

get_action_deltas() → ndarray

Returns:

deltas that will be applied for finger joint positions when openning or closing the gripper.

[left, right]. Defaults to None.

Return type:

np.ndarray

set_default_state(

joint_positions: ndarray,

) → None

Sets the default state of the gripper

Parameters:

joint_positions (np.ndarray) – joint positions of the left finger joint and the right finger joint respectively.

get_default_state() → ndarray

Gets the default state of the gripper

Returns:

joint positions of the left finger joint and the right finger joint respectively.

Return type:

np.ndarray

post_reset()

Reset the prim to its default state (position and orientation).

Note

For an articulation, in addition to configuring the root prim’s default position and spatial orientation (defined via the set_default_state method), the joint’s positions, velocities, and efforts (defined via the set_joints_default_state method) are imposed

Example:

>>> prim.post_reset()

set_joint_positions(positions: ndarray) → None

Parameters:

positions (np.ndarray) – joint positions of the left finger joint and the right finger joint respectively.

get_joint_positions() → ndarray

Returns:

joint positions of the left finger joint and the right finger joint respectively.

Return type:

np.ndarray

forward(

action: str,

) → ArticulationAction

calculates the ArticulationAction for all of the articulation joints that corresponds to “open”

or “close” actions.

Parameters:

action (str) – “open” or “close” as an abstract action.

Raises:

Exception – _description_

Returns:

articulation action to be passed to the articulation itself

(includes all joints of the articulation).

Return type:

ArticulationAction

apply_action(

control_actions: ArticulationAction,

) → None

Applies actions to all the joints of an articulation that corresponds to the ArticulationAction of the finger joints only.

Parameters:

control_actions (ArticulationAction) – ArticulationAction for the left finger joint and the right finger joint respectively.

apply_visual_material(

visual_material: VisualMaterial,

weaker_than_descendants: bool = False,

) → None

Apply visual material to the held prim and optionally its descendants.

Parameters:

• visual_material (VisualMaterial) – visual material to be applied to the held prim. Currently supports PreviewSurface, OmniPBR and OmniGlass.

• weaker_than_descendants (bool, optional) – True if the material shouldn’t override the descendants materials, otherwise False. Defaults to False.

Example:

>>> from isaacsim.core.api.materials import OmniGlass
>>>
>>> # create a dark-red glass visual material
>>> material = OmniGlass(
...     prim_path="/World/material/glass",  # path to the material prim to create
...     ior=1.25,
...     depth=0.001,
...     thin_walled=False,
...     color=np.array([0.5, 0.0, 0.0])
... )
>>> prim.apply_visual_material(material)

disable_rigid_body_physics() → None

Disable the rigid body physics

When disabled, the object will not be moved by external forces such as gravity and collisions

Example:

>>> prim.disable_rigid_body_physics()

enable_rigid_body_physics() → None

Enable the rigid body physics

When enabled, the object will be moved by external forces such as gravity and collisions

Example:

>>> prim.enable_rigid_body_physics()

get_angular_velocity()

Get the angular velocity of the rigid body

Returns:

current angular velocity of the the rigid prim. Shape (3,).

Return type:

np.ndarray

get_applied_visual_material() → VisualMaterial

Return the current applied visual material in case it was applied using apply_visual_material or it’s one of the following materials that was already applied before: PreviewSurface, OmniPBR and OmniGlass.

Returns:

the current applied visual material if its type is currently supported.

Return type:

VisualMaterial

Example:

>>> # given a visual material applied
>>> prim.get_applied_visual_material()
<isaacsim.core.api.materials.omni_glass.OmniGlass object at 0x7f36263106a0>

get_com() → float

Get the center of mass pose of the rigid body

Returns:

position of the center of mass of the rigid body. np.ndarray: orientation of the center of mass of the rigid body.

Return type:

np.ndarray

get_current_dynamic_state() → DynamicState

Get the current rigid body state (position, orientation and linear and angular velocities)

Returns:

the dynamic state of the rigid body prim

Return type:

DynamicState

Example:

>>> # for the example the rigid body is in free fall
>>> state = prim.get_current_dynamic_state()
>>> state
<isaacsim.core.utils.types.DynamicState object at 0x7f740b36f670>
>>> state.position
[  0.99999857   2.0000017  -74.2862    ]
>>> state.orientation
[ 1.0000000e+00 -2.3961178e-07 -4.9891562e-09  4.9388258e-09]
>>> state.linear_velocity
[  0.        0.      -38.09554]
>>> state.angular_velocity
[0. 0. 0.]

get_density() → float

Get the density of the rigid body

Returns:

density of the rigid body.

Return type:

float

Example:

>>> prim.get_density()
0

get_linear_velocity() → ndarray

Get the linear velocity of the rigid body

Returns:

current linear velocity of the the rigid prim. Shape (3,).

Return type:

np.ndarray

Example:

>>> prim.get_linear_velocity()
[ 1.0812164e-04  6.1415871e-05 -2.1341663e-04]

get_local_pose() → Tuple[ndarray, ndarray]

Get prim’s pose with respect to the local frame (the prim’s parent frame)

Returns:

first index is the position in the local frame (with shape (3, )). Second index is quaternion orientation (with shape (4, )) in the local frame

Return type:

Tuple[np.ndarray, np.ndarray]

Example:

>>> # if the prim is in position (1.0, 0.5, 0.0) with respect to the world frame
>>> position, orientation = prim.get_local_pose()
>>> position
[0. 0. 0.]
>>> orientation
[0. 0. 0.]

get_local_scale() → ndarray

Get prim’s scale with respect to the local frame (the parent’s frame)

Returns:

scale applied to the prim’s dimensions in the local frame. shape is (3, ).

Return type:

np.ndarray

Example:

>>> prim.get_local_scale()
[1. 1. 1.]

get_mass() → float

Get the mass of the rigid body

Returns:

mass of the rigid body in kg.

Return type:

float

Example:

>>> prim.get_mass()
0

get_sleep_threshold() → float

Get the threshold for the rigid body to enter a sleep state

Search for Rigid Body Dynamics > Sleeping in PhysX docs for more details

Returns:

Mass-normalized kinetic energy threshold below which

an actor may go to sleep. Range: [0, inf) Defaults: 0.00005 * tolerancesSpeed* tolerancesSpeed Units: distance^2 / second^2.

Return type:

float

Example:

>>> prim.get_sleep_threshold()
5e-05

get_visibility() → bool

Returns:

true if the prim is visible in stage. false otherwise.

Return type:

bool

Example:

>>> # get the visible state of an visible prim on the stage
>>> prim.get_visibility()
True

get_world_pose() → Tuple[ndarray, ndarray]

Get prim’s pose with respect to the world’s frame

Returns:

first index is the position in the world frame (with shape (3, )). Second index is quaternion orientation (with shape (4, )) in the world frame

Return type:

Tuple[np.ndarray, np.ndarray]

Example:

>>> # if the prim is in position (1.0, 0.5, 0.0) with respect to the world frame
>>> position, orientation = prim.get_world_pose()
>>> position
[1.  0.5 0. ]
>>> orientation
[1. 0. 0. 0.]

get_world_scale() → ndarray

Get prim’s scale with respect to the world’s frame

Returns:

scale applied to the prim’s dimensions in the world frame. shape is (3, ).

Return type:

np.ndarray

Example:

>>> prim.get_world_scale()
[1. 1. 1.]

is_valid() → bool

Check if the prim path has a valid USD Prim at it

Returns:

True is the current prim path corresponds to a valid prim in stage. False otherwise.

Return type:

bool

Example:

>>> # given an existing and valid prim
>>> prims.is_valid()
True

is_visual_material_applied() → bool

Check if there is a visual material applied

Returns:

True if there is a visual material applied. False otherwise.

Return type:

bool

Example:

>>> # given a visual material applied
>>> prim.is_visual_material_applied()
True

property name: str | None

Returns: str: name given to the prim when instantiating it. Otherwise None.

property non_root_articulation_link: bool

Used to query if the prim is a non root articulation link

Returns:

True if the prim itself is a non root link

Return type:

bool

Example:

>>> # for a wrapped articulation (where the root prim has the Physics Articulation Root property applied)
>>> prim.non_root_articulation_link
False

property prim: pxr.Usd.Prim

Returns: Usd.Prim: USD Prim object that this object holds.

property prim_path: str

Returns: str: prim path in the stage

set_angular_velocity(velocity: ndarray) → None

Set the angular velocity of the rigid body in stage

Warning

This method will immediately set the articulation state

Parameters:

velocity (np.ndarray) – angular velocity to set the rigid prim to. Shape (3,).

set_com(

position: ndarray,

orientation: ndarray,

) → None

Set the center of mass pose of the rigid body

Parameters:

• position (np.ndarray) – center of mass position. Shape (3,).

• orientation (np.ndarray) – center of mass orientation. Shape (4,).

set_density(density: float) → None

Set the density of the rigid body

Parameters:

mass (float) – density of the rigid body.

Example:

>>> prim.set_density(0.9)

set_linear_velocity(velocity: ndarray)

Set the linear velocity of the rigid body in stage

Warning

This method will immediately set the rigid prim state

Parameters:

velocity (np.ndarray) – linear velocity to set the rigid prim to. Shape (3,).

set_local_pose(

translation: Sequence[float] | None = None,

orientation: Sequence[float] | None = None,

) → None

Set prim’s pose with respect to the local frame (the prim’s parent frame).

Warning

This method will change (teleport) the prim pose immediately to the indicated value

Parameters:

• translation (Optional[Sequence[float]], optional) – translation in the local frame of the prim (with respect to its parent prim). shape is (3, ). Defaults to None, which means left unchanged.

• orientation (Optional[Sequence[float]], optional) – quaternion orientation in the local frame of the prim. quaternion is scalar-first (w, x, y, z). shape is (4, ). Defaults to None, which means left unchanged.

Hint

This method belongs to the methods used to set the prim state

Example:

>>> prim.set_local_pose(translation=np.array([1.0, 0.5, 0.0]), orientation=np.array([1., 0., 0., 0.]))

set_local_scale(

scale: Sequence[float] | None,

) → None

Set prim’s scale with respect to the local frame (the prim’s parent frame).

Parameters:

scale (Optional[Sequence[float]]) – scale to be applied to the prim’s dimensions. shape is (3, ). Defaults to None, which means left unchanged.

Example:

>>> # scale prim 10 times smaller
>>> prim.set_local_scale(np.array([0.1, 0.1, 0.1]))

set_mass(mass: float) → None

Set the mass of the rigid body

Parameters:

mass (float) – mass of the rigid body in kg.

Example:

>>> prim.set_mass(1.0)

set_sleep_threshold(threshold: float) → None

Set the threshold for the rigid body to enter a sleep state

Search for Rigid Body Dynamics > Sleeping in PhysX docs for more details

Parameters:

threshold (float) – Mass-normalized kinetic energy threshold below which an actor may go to sleep. Range: [0, inf) Defaults: 0.00005 * tolerancesSpeed* tolerancesSpeed Units: distance^2 / second^2.

Example:

>>> prim.set_sleep_threshold(1e-5)

set_visibility(visible: bool) → None

Set the visibility of the prim in stage

Parameters:

visible (bool) – flag to set the visibility of the usd prim in stage.

Example:

>>> # make prim not visible in the stage
>>> prim.set_visibility(visible=False)

set_world_pose(

position: Sequence[float] | None = None,

orientation: Sequence[float] | None = None,

) → None

Ses prim’s pose with respect to the world’s frame

Warning

This method will change (teleport) the prim pose immediately to the indicated value

Parameters:

• position (Optional[Sequence[float]], optional) – position in the world frame of the prim. shape is (3, ). Defaults to None, which means left unchanged.

• orientation (Optional[Sequence[float]], optional) – quaternion orientation in the world frame of the prim. quaternion is scalar-first (w, x, y, z). shape is (4, ). Defaults to None, which means left unchanged.

Hint

This method belongs to the methods used to set the prim state

Example:

>>> prim.set_world_pose(position=np.array([1.0, 0.5, 0.0]), orientation=np.array([1., 0., 0., 0.]))

class SurfaceGripper(

end_effector_prim_path: str,

translate: float = 0,

direction: str = 'x',

grip_threshold: float = 0.01,

force_limit: float = 1000000.0,

torque_limit: float = 10000.0,

bend_angle: float = 0.1308996938995747,

kp: float = 100.0,

kd: float = 100.0,

disable_gravity: bool = True,

)

Bases: Gripper

Provides high level functions to set/ get properties and actions of a surface gripper (a suction cup for example).

Parameters:

• end_effector_prim_path (str) – prim path of the Prim that corresponds to the gripper root/ end effector.

• translate (float, optional) – _description_. Defaults to 0.

• direction (str, optional) – _description_. Defaults to “x”.

• grip_threshold (float, optional) – _description_. Defaults to 0.01.

• force_limit (float, optional) – _description_. Defaults to 1.0e6.

• torque_limit (float, optional) – _description_. Defaults to 1.0e4.

• bend_angle (float, optional) – _description_. Defaults to np.pi/24.

• kp (float, optional) – _description_. Defaults to 1.0e2.

• kd (float, optional) – _description_. Defaults to 1.0e2.

• disable_gravity (bool, optional) – _description_. Defaults to True.

initialize(

physics_sim_view: omni.physics.tensors.SimulationView | None = None,

articulation_num_dofs: int | None = None,

) → None

Create a physics simulation view if not passed and creates a rigid prim view using physX tensor api.

This needs to be called after each hard reset (i.e stop + play on the timeline) before interacting with any of the functions of this class.

Parameters:

• physics_sim_view (omni.physics.tensors.SimulationView, optional) – current physics simulation view. Defaults to None

• articulation_num_dofs (int, optional) – num of dofs of the Articulation. Defaults to None.

close() → None

Applies actions to the articulation that closes the gripper (ex: to hold an object).

open() → None

Applies actions to the articulation that opens the gripper (ex: to release an object held).

update() → None

is_closed() → bool

set_translate(value: float) → None

set_direction(value: float) → None

set_force_limit(value: float) → None

set_torque_limit(value: float) → None

set_default_state(opened: bool)

Sets the default state of the gripper

Parameters:

opened (bool) – True if the surface gripper should start in an opened state. False otherwise.

get_default_state() → dict

Gets the default state of the gripper

Returns:

key is “opened” and value would be true if the surface gripper should start in an opened state. False otherwise.

Return type:

dict

post_reset()

Reset the prim to its default state (position and orientation).

Note

For an articulation, in addition to configuring the root prim’s default position and spatial orientation (defined via the set_default_state method), the joint’s positions, velocities, and efforts (defined via the set_joints_default_state method) are imposed

Example:

>>> prim.post_reset()

forward(

action: str,

) → ArticulationAction

calculates the ArticulationAction for all of the articulation joints that corresponds to “open”

or “close” actions.

Parameters:

action (str) – “open” or “close” as an abstract action.

Raises:

Exception – _description_

Returns:

articulation action to be passed to the articulation itself

(includes all joints of the articulation).

Return type:

ArticulationAction

apply_visual_material(

visual_material: VisualMaterial,

weaker_than_descendants: bool = False,

) → None

Apply visual material to the held prim and optionally its descendants.

Parameters:

• visual_material (VisualMaterial) – visual material to be applied to the held prim. Currently supports PreviewSurface, OmniPBR and OmniGlass.

• weaker_than_descendants (bool, optional) – True if the material shouldn’t override the descendants materials, otherwise False. Defaults to False.

Example:

>>> from isaacsim.core.api.materials import OmniGlass
>>>
>>> # create a dark-red glass visual material
>>> material = OmniGlass(
...     prim_path="/World/material/glass",  # path to the material prim to create
...     ior=1.25,
...     depth=0.001,
...     thin_walled=False,
...     color=np.array([0.5, 0.0, 0.0])
... )
>>> prim.apply_visual_material(material)

disable_rigid_body_physics() → None

Disable the rigid body physics

When disabled, the object will not be moved by external forces such as gravity and collisions

Example:

>>> prim.disable_rigid_body_physics()

enable_rigid_body_physics() → None

Enable the rigid body physics

When enabled, the object will be moved by external forces such as gravity and collisions

Example:

>>> prim.enable_rigid_body_physics()

get_angular_velocity()

Get the angular velocity of the rigid body

Returns:

current angular velocity of the the rigid prim. Shape (3,).

Return type:

np.ndarray

get_applied_visual_material() → VisualMaterial

Return the current applied visual material in case it was applied using apply_visual_material or it’s one of the following materials that was already applied before: PreviewSurface, OmniPBR and OmniGlass.

Returns:

the current applied visual material if its type is currently supported.

Return type:

VisualMaterial

Example:

>>> # given a visual material applied
>>> prim.get_applied_visual_material()
<isaacsim.core.api.materials.omni_glass.OmniGlass object at 0x7f36263106a0>

get_com() → float

Get the center of mass pose of the rigid body

Returns:

position of the center of mass of the rigid body. np.ndarray: orientation of the center of mass of the rigid body.

Return type:

np.ndarray

get_current_dynamic_state() → DynamicState

Get the current rigid body state (position, orientation and linear and angular velocities)

Returns:

the dynamic state of the rigid body prim

Return type:

DynamicState

Example:

>>> # for the example the rigid body is in free fall
>>> state = prim.get_current_dynamic_state()
>>> state
<isaacsim.core.utils.types.DynamicState object at 0x7f740b36f670>
>>> state.position
[  0.99999857   2.0000017  -74.2862    ]
>>> state.orientation
[ 1.0000000e+00 -2.3961178e-07 -4.9891562e-09  4.9388258e-09]
>>> state.linear_velocity
[  0.        0.      -38.09554]
>>> state.angular_velocity
[0. 0. 0.]

get_density() → float

Get the density of the rigid body

Returns:

density of the rigid body.

Return type:

float

Example:

>>> prim.get_density()
0

get_linear_velocity() → ndarray

Get the linear velocity of the rigid body

Returns:

current linear velocity of the the rigid prim. Shape (3,).

Return type:

np.ndarray

Example:

>>> prim.get_linear_velocity()
[ 1.0812164e-04  6.1415871e-05 -2.1341663e-04]

get_local_pose() → Tuple[ndarray, ndarray]

Get prim’s pose with respect to the local frame (the prim’s parent frame)

Returns:

first index is the position in the local frame (with shape (3, )). Second index is quaternion orientation (with shape (4, )) in the local frame

Return type:

Tuple[np.ndarray, np.ndarray]

Example:

>>> # if the prim is in position (1.0, 0.5, 0.0) with respect to the world frame
>>> position, orientation = prim.get_local_pose()
>>> position
[0. 0. 0.]
>>> orientation
[0. 0. 0.]

get_local_scale() → ndarray

Get prim’s scale with respect to the local frame (the parent’s frame)

Returns:

scale applied to the prim’s dimensions in the local frame. shape is (3, ).

Return type:

np.ndarray

Example:

>>> prim.get_local_scale()
[1. 1. 1.]

get_mass() → float

Get the mass of the rigid body

Returns:

mass of the rigid body in kg.

Return type:

float

Example:

>>> prim.get_mass()
0

get_sleep_threshold() → float

Get the threshold for the rigid body to enter a sleep state

Search for Rigid Body Dynamics > Sleeping in PhysX docs for more details

Returns:

Mass-normalized kinetic energy threshold below which

an actor may go to sleep. Range: [0, inf) Defaults: 0.00005 * tolerancesSpeed* tolerancesSpeed Units: distance^2 / second^2.

Return type:

float

Example:

>>> prim.get_sleep_threshold()
5e-05

get_visibility() → bool

Returns:

true if the prim is visible in stage. false otherwise.

Return type:

bool

Example:

>>> # get the visible state of an visible prim on the stage
>>> prim.get_visibility()
True

get_world_pose() → Tuple[ndarray, ndarray]

Get prim’s pose with respect to the world’s frame

Returns:

first index is the position in the world frame (with shape (3, )). Second index is quaternion orientation (with shape (4, )) in the world frame

Return type:

Tuple[np.ndarray, np.ndarray]

Example:

>>> # if the prim is in position (1.0, 0.5, 0.0) with respect to the world frame
>>> position, orientation = prim.get_world_pose()
>>> position
[1.  0.5 0. ]
>>> orientation
[1. 0. 0. 0.]

get_world_scale() → ndarray

Get prim’s scale with respect to the world’s frame

Returns:

scale applied to the prim’s dimensions in the world frame. shape is (3, ).

Return type:

np.ndarray

Example:

>>> prim.get_world_scale()
[1. 1. 1.]

is_valid() → bool

Check if the prim path has a valid USD Prim at it

Returns:

True is the current prim path corresponds to a valid prim in stage. False otherwise.

Return type:

bool

Example:

>>> # given an existing and valid prim
>>> prims.is_valid()
True

is_visual_material_applied() → bool

Check if there is a visual material applied

Returns:

True if there is a visual material applied. False otherwise.

Return type:

bool

Example:

>>> # given a visual material applied
>>> prim.is_visual_material_applied()
True

property name: str | None

Returns: str: name given to the prim when instantiating it. Otherwise None.

property non_root_articulation_link: bool

Used to query if the prim is a non root articulation link

Returns:

True if the prim itself is a non root link

Return type:

bool

Example:

>>> # for a wrapped articulation (where the root prim has the Physics Articulation Root property applied)
>>> prim.non_root_articulation_link
False

property prim: pxr.Usd.Prim

Returns: Usd.Prim: USD Prim object that this object holds.

property prim_path: str

Returns: str: prim path in the stage

set_angular_velocity(velocity: ndarray) → None

Set the angular velocity of the rigid body in stage

Warning

This method will immediately set the articulation state

Parameters:

velocity (np.ndarray) – angular velocity to set the rigid prim to. Shape (3,).

set_com(

position: ndarray,

orientation: ndarray,

) → None

Set the center of mass pose of the rigid body

Parameters:

• position (np.ndarray) – center of mass position. Shape (3,).

• orientation (np.ndarray) – center of mass orientation. Shape (4,).

set_density(density: float) → None

Set the density of the rigid body

Parameters:

mass (float) – density of the rigid body.

Example:

>>> prim.set_density(0.9)

set_linear_velocity(velocity: ndarray)

Set the linear velocity of the rigid body in stage

Warning

This method will immediately set the rigid prim state

Parameters:

velocity (np.ndarray) – linear velocity to set the rigid prim to. Shape (3,).

set_local_pose(

translation: Sequence[float] | None = None,

orientation: Sequence[float] | None = None,

) → None

Set prim’s pose with respect to the local frame (the prim’s parent frame).

Warning

This method will change (teleport) the prim pose immediately to the indicated value

Parameters:

• translation (Optional[Sequence[float]], optional) – translation in the local frame of the prim (with respect to its parent prim). shape is (3, ). Defaults to None, which means left unchanged.

• orientation (Optional[Sequence[float]], optional) – quaternion orientation in the local frame of the prim. quaternion is scalar-first (w, x, y, z). shape is (4, ). Defaults to None, which means left unchanged.

Hint

This method belongs to the methods used to set the prim state

Example:

>>> prim.set_local_pose(translation=np.array([1.0, 0.5, 0.0]), orientation=np.array([1., 0., 0., 0.]))

set_local_scale(

scale: Sequence[float] | None,

) → None

Set prim’s scale with respect to the local frame (the prim’s parent frame).

Parameters:

scale (Optional[Sequence[float]]) – scale to be applied to the prim’s dimensions. shape is (3, ). Defaults to None, which means left unchanged.

Example:

>>> # scale prim 10 times smaller
>>> prim.set_local_scale(np.array([0.1, 0.1, 0.1]))

set_mass(mass: float) → None

Set the mass of the rigid body

Parameters:

mass (float) – mass of the rigid body in kg.

Example:

>>> prim.set_mass(1.0)

set_sleep_threshold(threshold: float) → None

Set the threshold for the rigid body to enter a sleep state

Search for Rigid Body Dynamics > Sleeping in PhysX docs for more details

Parameters:

threshold (float) – Mass-normalized kinetic energy threshold below which an actor may go to sleep. Range: [0, inf) Defaults: 0.00005 * tolerancesSpeed* tolerancesSpeed Units: distance^2 / second^2.

Example:

>>> prim.set_sleep_threshold(1e-5)

set_visibility(visible: bool) → None

Set the visibility of the prim in stage

Parameters:

visible (bool) – flag to set the visibility of the usd prim in stage.

Example:

>>> # make prim not visible in the stage
>>> prim.set_visibility(visible=False)

set_world_pose(

position: Sequence[float] | None = None,

orientation: Sequence[float] | None = None,

) → None

Ses prim’s pose with respect to the world’s frame

Warning

This method will change (teleport) the prim pose immediately to the indicated value

Parameters:

• position (Optional[Sequence[float]], optional) – position in the world frame of the prim. shape is (3, ). Defaults to None, which means left unchanged.

• orientation (Optional[Sequence[float]], optional) – quaternion orientation in the world frame of the prim. quaternion is scalar-first (w, x, y, z). shape is (4, ). Defaults to None, which means left unchanged.

Hint

This method belongs to the methods used to set the prim state

Example:

>>> prim.set_world_pose(position=np.array([1.0, 0.5, 0.0]), orientation=np.array([1., 0., 0., 0.]))