isaaclab.scene_data

Sub-package containing the scene data provider and backend interface.

The SceneDataProvider bridges physics simulation backends and the consumers that read scene transforms (renderers and visualizers). Physics backends implement SceneDataBackend to expose their current transforms in one of the SceneDataFormat Warp struct variants; the provider converts and remaps them on demand for each consumer.

This package is deliberately separate from isaaclab.scene so that physics backends (isaaclab_physx, isaaclab_newton) can subclass SceneDataBackend without pulling isaaclab.scene into the AppLauncher pre-launch import chain.

Classes

SceneDataProvider
SceneDataBackend
SceneDataFormat	Warp struct variants describing the transform layouts that a SceneDataBackend may publish to consumers.

Scene Data Provider

class isaaclab.scene_data.SceneDataProvider

Bases: object

Methods:

__init__(backend)	Initialize the scene data provider.
set_interactive_scene(scene)	Attach the active interactive scene for scene-owned sensor discovery.
get_interactive_scene()	Return the registered interactive scene, if available.
get_camera_sensors()	Return Isaac Lab camera sensors keyed by scene sensor name.
get_usd_stage()	Return the USD stage for callers using the older method-style API.
get_camera_transforms()	Per-camera, per-environment world transforms discovered from USD.
get_transforms(output[, mapping, ...])	Convert sim backend transforms into the requested output format.
init_output(output)	Allocate any uninitialized fields in output with empty Warp arrays.
create_mapping(paths)	Create an index mapping from sim backend transforms to desired output ordering.

Attributes:

transform_count	Number of transforms available from the sim backend.
usd_stage	Pixar Usd.Stage for visualizers and renderers that walk USD.
num_envs	Number of environments discovered from /World/envs/env_<id> prims.

__init__(backend: SceneDataBackend)

Initialize the scene data provider.

Parameters:

backend – The simulation backend that supplies raw transform data.

set_interactive_scene(scene: Any) → None

Attach the active interactive scene for scene-owned sensor discovery.

get_interactive_scene() → Any | None

Return the registered interactive scene, if available.

get_camera_sensors() → dict[str, Any]

Return Isaac Lab camera sensors keyed by scene sensor name.

property transform_count: int

Number of transforms available from the sim backend.

property usd_stage: Usd.Stage | None

Pixar Usd.Stage for visualizers and renderers that walk USD.

Resolves to isaaclab.sim.SimulationContext.stage, falling back to omni.usd.get_context().get_stage() when the simulation context has no cached stage. Returns None on Newton-only headless runs without a USD stage.

get_usd_stage() → Usd.Stage | None

Return the USD stage for callers using the older method-style API.

property num_envs: int

Number of environments discovered from /World/envs/env_<id> prims.

Cached on first call. Returns 0 when no USD stage is available or when no /World/envs/env_<id> prims exist.

get_camera_transforms() → dict[str, Any] | None

Per-camera, per-environment world transforms discovered from USD.

Returns:

Dictionary with keys order (list of template prim paths using env_%d), positions and orientations (per-camera, per-env lists, with None for absent envs), and num_envs. Returns None when no USD stage is available.

get_transforms(output: SceneDataFormat.Vec3_Quat | SceneDataFormat.Transform | SceneDataFormat.Matrix44 | SceneDataFormat.Vec3_Matrix33, mapping: wp.array(dtype=wp.int32) | None = None, allow_passthrough: bool = True) → bool

Convert sim backend transforms into the requested output format.

When the backend’s native format matches output, data is either passed through by reference (allow_passthrough=True) or deep-copied. Otherwise a Warp conversion kernel is launched to transform the data, applying mapping to reorder the output if provided.

Parameters:

• output – A pre-allocated SceneDataFormat struct that determines the target format. Uninitialized (None) fields are allocated automatically when a conversion kernel is needed.

• mapping – Optional index remapping array produced by create_mapping(). When None, input and output indices are identical.

• allow_passthrough – If True and the formats already match, the output struct’s fields are set to reference the input arrays directly (zero-copy). If False, the data is always copied.

Returns:

True if the conversion succeeded, False if no suitable conversion kernel exists for the input/output format pair.

init_output(output: Vec3_Quat | Transform | Matrix44 | Vec3_Matrix33)

Allocate any uninitialized fields in output with empty Warp arrays.

Only fields that are currently None are allocated; already-initialized fields are left untouched.

Parameters:

output – A SceneDataFormat struct whose None-valued fields will be replaced with empty arrays of length transform_count.

create_mapping(paths: list[str | None]) → wp.array(dtype=wp.int32) | None

Create an index mapping from sim backend transforms to desired output ordering.

For each transform in the sim backend, the resulting array stores the index into paths where that transform should be written. Transforms whose path does not appear in paths (or maps to None) receive an index of -1 and are skipped during conversion.

Parameters:

paths – Desired output ordering expressed as prim paths. Use None for slots that should not receive any transform.

Returns:

A Warp int32 array of length transform_count containing the remapped indices, or None if the sim backend provides no transform paths or if no mapping is needed.

Scene Data Backend

class isaaclab.scene_data.SceneDataBackend

Bases: object

Attributes:

transforms	Return the sim backends transforms as one of the SceneDataFormat structs.
transform_count	Return the number of transforms in the sim backend.
transform_paths	Return the paths for each transform.

property transforms: Vec3_Quat | Transform | Matrix44 | Vec3_Matrix33

Return the sim backends transforms as one of the SceneDataFormat structs.

property transform_count: int

Return the number of transforms in the sim backend.

property transform_paths: list[str]

Return the paths for each transform.

class isaaclab.scene_data.SceneDataFormat

Bases: object

Warp struct variants describing the transform layouts that a SceneDataBackend may publish to consumers.

Classes:

Vec3_Quat	Separate position and quaternion arrays.
Vec3_Matrix33	Separate position and rotation-matrix arrays.
Transform	Packed warp transforms (position + quaternion).
Matrix44	Packed 4x4 homogeneous transform matrices.

class Vec3_Quat

Bases: object

Separate position and quaternion arrays.

Attributes:

positions	Per-transform positions [m].
orientations	Per-transform orientations as quaternions.

positions: warp.array = None

Per-transform positions [m].

orientations: warp.array = None

Per-transform orientations as quaternions.

class Vec3_Matrix33

Bases: object

Separate position and rotation-matrix arrays.

Attributes:

positions	Per-transform positions [m].
orientations	Per-transform orientations as 3x3 rotation matrices.

positions: warp.array = None

Per-transform positions [m].

orientations: warp.array = None

Per-transform orientations as 3x3 rotation matrices.

class Transform

Bases: object

Packed warp transforms (position + quaternion).

Attributes:

transforms

Per-transform packed position + orientation transforms [m, -].

transforms: warp.array = None

Per-transform packed position + orientation transforms [m, -].

class Matrix44

Bases: object

Packed 4x4 homogeneous transform matrices.

Attributes:

matrices

Per-transform 4x4 homogeneous transform matrices [m].

matrices: warp.array = None

Per-transform 4x4 homogeneous transform matrices [m].