API#

Python API#

Commands

`IsaacSensorCreatePrim`	Command for creating Isaac sensor prims in the USD stage.
`IsaacSensorCreateContactSensor`	Creates an Isaac Contact Sensor prim in the USD stage.
`IsaacSensorCreateImuSensor`	Command for creating an IMU (Inertial Measurement Unit) sensor prim in the stage.

Sensors

`ContactSensor`	A sensor that detects physical contact and measures contact forces.
`EsSensorReading`	A container for effort sensor measurement data.
`EffortSensor`	A sensor for measuring joint effort (force/torque) in articulated bodies.
`IMUSensor`	A physics-based IMU (Inertial Measurement Unit) sensor that measures linear acceleration, angular velocity, and orientation.

Commands#

class IsaacSensorCreatePrim(*args: Any, **kwargs: Any)#

Bases: Command

Command for creating Isaac sensor prims in the USD stage.

This command creates a new sensor prim using the specified Isaac sensor schema type and applies the provided transformation properties. The sensor is created at the specified path with the given translation and orientation. It serves as a base command for creating various types of Isaac sensors.

Parameters:

path – USD path where the sensor prim will be created.
parent – Parent prim path under which the sensor will be created.
translation – Translation vector for positioning the sensor in 3D space.
orientation – Quaternion rotation for orienting the sensor.
schema_type – Isaac sensor schema type to apply to the created prim.

class IsaacSensorCreateContactSensor(*args: Any, **kwargs: Any)#

Bases: Command

Creates an Isaac Contact Sensor prim in the USD stage.

This command creates a contact sensor that detects physical contact between objects in a simulation. The sensor monitors contact forces and reports when they fall within specified threshold ranges. It automatically applies the PhysX Contact Report API to the parent prim to enable contact detection.

Parameters:

path – USD path where the contact sensor prim will be created.
parent – USD path of the parent prim. Must be specified for successful sensor creation.
min_threshold – Minimum contact force threshold for detection.
max_threshold – Maximum contact force threshold for detection.
color – RGBA color values for sensor visualization.
radius – Detection radius for the contact sensor. Negative values use default behavior.
sensor_period – Data collection frequency in seconds. Negative values use default behavior.
translation – 3D translation offset from the parent prim’s origin.

class IsaacSensorCreateImuSensor(*args: Any, **kwargs: Any)#

Bases: Command

Command for creating an IMU (Inertial Measurement Unit) sensor prim in the stage.

This command creates an Isaac IMU sensor that can measure linear acceleration, angular velocity, and orientation. The sensor supports configurable filter sizes for smoothing the measured values and can be positioned and oriented relative to its parent prim.

Parameters:

path – USD path where the IMU sensor prim will be created.
parent – USD path of the parent prim to attach the sensor to.
sensor_period – Sensor update period in simulation time. Negative values use the default period.
translation – Local translation offset from the parent prim.
orientation – Local rotation offset from the parent prim as a quaternion (w, x, y, z).
linear_acceleration_filter_size – Number of samples to use for linear acceleration filtering.
angular_velocity_filter_size – Number of samples to use for angular velocity filtering.
orientation_filter_size – Number of samples to use for orientation filtering.

Sensors#

Bases: BaseSensor

A sensor that detects physical contact and measures contact forces.

ContactSensor creates and manages a contact sensor that can detect when objects come into contact with it and measure the magnitude of contact forces. The sensor must be attached to a prim that has the UsdPhysics.CollisionAPI enabled. It provides real-time contact detection with configurable thresholds and can report detailed contact information including positions, normals, and impulses.

The sensor can operate at a specified frequency or time step and includes filtering capabilities through min/max thresholds to ignore contacts below or above certain force values. It supports both basic contact detection (boolean in-contact state and force magnitude) and detailed contact data (individual contact points with full physics information).

Parameters:

prim_path – USD path where the contact sensor will be created.
name – Name identifier for the sensor.
frequency – Sensor update frequency in Hz. Cannot be used with dt.
dt – Sensor update time step in seconds. Cannot be used with frequency.
translation – Local translation offset of the sensor relative to its parent prim.
position – World position where the sensor should be placed.
min_threshold – Minimum force threshold below which contacts are ignored.
max_threshold – Maximum force threshold above which contacts are clamped.
radius – Detection radius of the contact sensor. Negative values indicate unlimited radius.

Raises:

Exception – If both frequency and dt are specified simultaneously.
Exception – If the parent prim does not have UsdPhysics.CollisionAPI enabled.
Exception – If sensor creation fails.

add_raw_contact_data_to_frame()#: Add raw contact data to the current frame for detailed contact information.

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)

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_current_frame()#

Get the current sensor frame data including contact information.

Returns:: Dictionary containing contact data with keys for time, physics step, contact status, force, and number of contacts.

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_dt() → float#

Get the sensor sampling time interval.

Returns:: The time interval between sensor readings in seconds.

get_frequency() → int#

Get the current sensor sampling frequency.

Returns:: The sensor frequency in Hz.

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_max_threshold() → float#

Maximum force threshold for contact detection.

Returns:: The maximum force threshold value.

get_min_threshold() → float#

Minimum force threshold for contact detection.

Returns:: The minimum force threshold value.

get_radius() → float#

Radius of the contact sensor detection area.

Returns:: The radius value of the sensor detection area.

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.]

initialize(physics_sim_view=None)#

Initialize the contact sensor.

Parameters:: physics_sim_view – Physics simulation view to initialize with.

is_paused() → bool#

Check if the contact sensor is currently paused.

Returns:: True if the sensor is paused, False otherwise.

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

pause()#: Pause sensor data collection by disabling the contact sensor.

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()

remove_raw_contact_data_from_frame()#: Remove raw contact data from the current frame.

resume()#: Resume sensor data collection by enabling the contact sensor.

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_dt(value: float)#

Sets the sensor period (time step) for the contact sensor.

Parameters:: value – The sensor period in seconds.

set_frequency(value: float)#

Set the sensor sampling frequency.

Parameters:: value – The frequency in Hz to set for the sensor.

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_max_threshold(value: float)#

Sets the maximum force threshold for contact detection.

Parameters:: value – The maximum threshold value.

set_min_threshold(value: float)#

Sets the minimum force threshold for contact detection.

Parameters:: value – The minimum threshold value.

set_radius(value: float)#

Sets the radius of the contact sensor detection area.

Parameters:: value – The radius value to set.

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.]))

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

class EsSensorReading( is_valid: bool = False, time: float = 0, value: float = 0, )#

Bases: object

A container for effort sensor measurement data.

This class encapsulates a single reading from an effort sensor, containing the measured value, timestamp, and validity status. It is used by EffortSensor to store and manage sensor data in buffers for interpolation and retrieval.

Parameters:

is_valid – Whether the sensor reading contains valid data.
time – Simulation time when the measurement was taken.
value – The measured effort value from the sensor.

class EffortSensor( prim_path: str, sensor_period: float = -1, use_latest_data: bool = False, enabled: bool = True, )#

Bases: SingleArticulation

A sensor for measuring joint effort (force/torque) in articulated bodies.

This sensor monitors the effort applied to a specific joint in an articulated body during physics simulation. It provides configurable sampling rates and data interpolation capabilities for accurate measurements. The sensor automatically manages data acquisition through physics simulation callbacks and maintains internal buffers for temporal data processing.

Parameters:

prim_path – Full USD path to the joint, including the articulated body path and joint name (e.g., “/World/Robot/joint_name”).
sensor_period – Time interval between sensor readings in seconds. If negative or less than the physics step size, readings are taken at every physics step.
use_latest_data – Whether to always return the most recent measurement instead of interpolated values.
enabled – Whether the sensor is actively collecting data.

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)

change_buffer_size(new_buffer_size: int)#

Resize the sensor data buffers to a new size.

Adjusts both the main sensor reading buffer and interpolation buffer to the specified size.

Parameters:: new_buffer_size – New size for the sensor data buffers.

disable_gravity() → None#

Keep gravity from affecting the robot

Example:

>>> prim.disable_gravity()

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.

Forces and torques are reported in the local body reference frame (child joint frame of the link’s incoming joint).

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_sensor_reading( interpolation_function=None, use_latest_data=False, ) → EsSensorReading#

Get the current sensor reading with optional interpolation.

Returns either the latest reading or an interpolated value based on sensor period and timing. Handles cases where sensor frequency differs from physics step frequency.

Parameters:

interpolation_function – Custom interpolation function to use instead of linear interpolation.
use_latest_data – Whether to force using the most recent data regardless of sensor period.

Returns:

Sensor reading containing timestamp, effort value, and validity status.

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_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

initialize( physics_sim_view: omni.physics.tensors.SimulationView = None, ) → None#

Create a physics simulation view if not passed and an articulation view using PhysX tensor API

Note

If the articulation has been added to the world scene (e.g., world.scene.add(prim)), it will be automatically initialized when the world is reset (e.g., world.reset()).

Warning

This method needs to be called after each hard reset (e.g., Stop + Play on the timeline) before interacting with any other class method.

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

Example:

>>> prim.initialize()

initialize_callbacks()#

Initialize physics and timeline event callbacks for the effort sensor.

Sets up callbacks for physics step events, stage opening events, and timeline play/stop events to manage sensor data acquisition and state reset.

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

lerp(start: float, end: float, time: float) → float#

Perform linear interpolation between two values.

Parameters:

start – Starting value.
end – Ending value.
time – Interpolation factor between 0 and 1.

Returns:

Interpolated value between start and end.

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()

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,).

update_dof_name(dof_name: str)#

Update the degree of freedom name for effort measurement.

Changes which joint the sensor monitors for effort data. Requires at least 3 physics steps to have passed for proper initialization.

Parameters:: dof_name – Name of the joint degree of freedom to monitor.

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

property handles_initialized: bool#

Check if articulation handler is initialized

Returns:: whether the handler was initialized
Return type:: bool

Example:

>>> prim.handles_initialized
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

Bases: BaseSensor

A physics-based IMU (Inertial Measurement Unit) sensor that measures linear acceleration, angular velocity, and orientation.

This sensor provides inertial measurements from a simulated IMU attached to a physics body. It measures three-axis linear acceleration, three-axis angular velocity, and orientation as a quaternion. The sensor supports configurable sampling rates and filtering for each measurement type.

The sensor can be created at an existing prim path or will automatically create a new IMU prim if the path doesn’t exist. When creating a new prim, it uses physics simulation settings to determine default timing parameters.

Parameters:

prim_path – USD path where the IMU sensor prim is located or will be created.
name – Identifier name for the sensor instance.
frequency – Sampling frequency in Hz for sensor readings. Cannot be specified together with dt.
dt – Time interval in seconds between sensor readings. Cannot be specified together with frequency.
translation – Local translation offset of the sensor relative to its parent body.
position – Local position offset of the sensor relative to its parent body.
orientation – Local orientation offset of the sensor as a quaternion relative to its parent body.
linear_acceleration_filter_size – Number of samples for moving average filter applied to linear acceleration measurements.
angular_velocity_filter_size – Number of samples for moving average filter applied to angular velocity measurements.
orientation_filter_size – Number of samples for moving average filter applied to orientation measurements.

Raises:

Exception – If both frequency and dt are specified simultaneously.
Exception – If IMU sensor prim creation fails at the specified path.

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)

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_current_frame(read_gravity=True) → dict#

Gets the current sensor reading frame containing IMU data.

Parameters:

read_gravity – Whether to include gravity in the linear acceleration reading.

Returns:

‘lin_acc’: Linear acceleration as a 3D tensor
’ang_vel’: Angular velocity as a 3D tensor
’orientation’: Orientation quaternion as a 4D tensor
’time’: Sensor reading timestamp
’physics_step’: Current physics simulation step

Return type:

Dictionary containing sensor data with keys

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_dt() → float#

Get the current IMU sensor sampling period.

Returns:: The sampling period in seconds.

get_frequency() → int#

Get the current IMU sensor sampling frequency.

Returns:: The sampling frequency in Hz.

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_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.]

initialize(physics_sim_view=None)#

Initialize the IMU sensor.

Parameters:: physics_sim_view – The physics simulation view to use for initialization.

is_paused() → bool#

Check if the IMU sensor is currently paused.

Returns:: True if the sensor is paused, False if enabled.

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

pause()#: Pause the IMU sensor by disabling it.

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()

resume()#: Resume the IMU sensor by enabling it.

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_dt(value: float)#

Set the IMU sensor sampling period.

Parameters:: value – The sampling period in seconds.

set_frequency(value: int)#

Set the IMU sensor sampling frequency.

Parameters:: value – The sampling frequency in Hz.

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_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.]))

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