URDF Support

rerun.urdf

UrdfJoint

A URDF joint with properties and transform computation.

axis property

axis: tuple[float, float, float]

Axis of the joint.

child_link property

child_link: str

Name of the child link.

joint_type property

joint_type: str

Type of the joint (revolute, continuous, prismatic, fixed, etc.).

limit_effort property

limit_effort: float

Effort limit of the joint.

limit_lower property

limit_lower: float

Lower limit of the joint.

limit_upper property

limit_upper: float

Upper limit of the joint.

limit_velocity property

limit_velocity: float

Velocity limit of the joint.

mimic property

mimic: UrdfMimic | None

Mimic-tag specification, or None if this joint is not a mimic joint.

name property

name: str

Name of the joint.

origin_rpy property

origin_rpy: tuple[float, float, float]

Origin of the joint (rotation in roll, pitch, yaw).

origin_xyz property

origin_xyz: tuple[float, float, float]

Origin of the joint (translation).

parent_link property

parent_link: str

Name of the parent link.

compute_transform

def compute_transform(
    value: float, clamp: bool = True
) -> Transform3D

Compute a Transform3D for this joint at the given value.

PARAMETER	DESCRIPTION
value	Joint angle in radians (revolute/continuous) or distance in meters (prismatic). Ignored for fixed joints. Values outside limits are clamped with a warning if clamp is True. TYPE: float
clamp	Whether to clamp & warn about values outside joint limits. TYPE: bool DEFAULT: True

RETURNS	DESCRIPTION
Transform3D	Transform with rotation, translation, parent_frame, and child_frame ready to log.

compute_transform_columns

def compute_transform_columns(
    values: Sequence[float], *, clamp: bool = True
) -> ComponentColumnList

Compute transforms for this joint at multiple values, returning columnar data for use with send_columns.

PARAMETER	DESCRIPTION
values	Joint values: angles in radians (revolute/continuous) or distances in meters (prismatic). Values outside limits are clamped with a warning if clamp is True. TYPE: Sequence[float]
clamp	Whether to clamp & warn about values outside joint limits. TYPE: bool DEFAULT: True

RETURNS	DESCRIPTION
ComponentColumnList	Columnar transform data ready for use with rerun.send_columns.

UrdfLink

A URDF link.

name property

name: str

Name of the link.

UrdfMimic

A URDF <mimic> tag specification.

A mimic joint's value is derived from a driver joint as value = multiplier * driver_value + offset.

joint property

joint: str

Name of the driver joint.

multiplier property

multiplier: float

Multiplier applied to the driver joint's value (defaults to 1.0).

offset property

offset: float

Offset added after multiplying the driver joint's value (defaults to 0.0).

UrdfTree

A URDF robot model with joints and links.

Use log_urdf_to_recording to log the full model (geometry + static transforms), then animate individual joints by logging archetypes.Transform3D computed via UrdfJoint.compute_transform.

frame_prefix property

frame_prefix: str | None

The frame prefix, if set.

name property

name: str

Name of the robot defined in this URDF.

compute_joint_transform_batches

def compute_joint_transform_batches(
    names: Array, values: Array, *, clamp: bool = False
) -> Array

Compute batches of 3D transform components from Arrow list arrays containing joint names and values.

names must be a ListArray with Utf8 values. values must be a ListArray with values castable to Float64.

The output is a ListArray with translation, quaternion, parent_frame, and child_frame fields and the same outer row count as the inputs.

Note: this is intended as a helper for lens pipelines, where you would usually pipe this output through an additional lens that scatters each batch into final Transform3D component rows.

PARAMETER	DESCRIPTION
names	Joint names for each row. TYPE: Array
values	Joint values for each row. TYPE: Array
clamp	Whether to clamp & warn about values outside joint limits. TYPE: bool DEFAULT: False

RETURNS	DESCRIPTION
Array	Transform batches with one outer row for each input row.

from_file_path staticmethod

def from_file_path(
    path: str | Path,
    entity_path_prefix: str | None = None,
    *,
    frame_prefix: str | None = None,
    static_transform_entity_path: str | None = None,
) -> UrdfTree

Load a URDF file from the given path.

PARAMETER	DESCRIPTION
path	Path to the URDF file. TYPE: str | Path
entity_path_prefix	Optional entity path prefix. TYPE: str | None DEFAULT: None
frame_prefix	Optional prefix for all frame IDs. Use to load the same URDF multiple times with unique frames. TYPE: str | None DEFAULT: None
static_transform_entity_path	Optional entity path to use when logging static transforms. If omitted, defaults to /tf_static. This path is not affected by entity_path_prefix. TYPE: str | None DEFAULT: None

get_collision_geometry_paths

def get_collision_geometry_paths(
    link: str | UrdfLink,
) -> list[str]

Get the entity paths for all collision geometries of the given link, if any.

PARAMETER	DESCRIPTION
link	The link for which to retrieve the collision geometry entity paths, either by name or as an UrdfLink instance. TYPE: str | UrdfLink

get_joint_by_name

def get_joint_by_name(joint_name: str) -> UrdfJoint | None

Get a joint by name.

PARAMETER	DESCRIPTION
joint_name	Name of the joint. TYPE: str

get_joint_child

def get_joint_child(joint: UrdfJoint) -> UrdfLink

Get the child link of a joint.

PARAMETER	DESCRIPTION
joint	The joint whose child link to retrieve. TYPE: UrdfJoint

get_link_by_name

def get_link_by_name(link_name: str) -> UrdfLink | None

Get a link by name.

PARAMETER	DESCRIPTION
link_name	Name of the link. TYPE: str

get_visual_geometry_paths

def get_visual_geometry_paths(
    link: str | UrdfLink,
) -> list[str]

Get the entity paths for all visual geometries of the given link, if any.

PARAMETER	DESCRIPTION
link	The link for which to get visual geometry paths, either by name or as an UrdfLink instance. TYPE: str | UrdfLink

joints

def joints() -> list[UrdfJoint]

Get all joints in the URDF.

log_urdf_to_recording

def log_urdf_to_recording(
    recording: RecordingStream | None = None,
) -> None

Log the full robot model (geometry + static transforms) to a recording stream.

This can be used as alternative to rerun.log_file_from_path for URDF files, especially in cases where you need the extra configuration options of UrdfTree (e.g. frame_prefix for multi-robot setups).

PARAMETER	DESCRIPTION
recording	The recording stream to log to. If None, the current active recording is used. TYPE: RecordingStream | None DEFAULT: None

root_link

def root_link() -> UrdfLink

Get the root link of the URDF.

stream

def stream(
    *, include_joint_transforms: bool = True
) -> LazyChunkStream

Return a lazy stream over chunks emitted from this URDF tree.

Warning

This method is experimental and returns the experimental rerun.experimental.LazyChunkStream API.

PARAMETER	DESCRIPTION
include_joint_transforms	Whether to include the static joint transforms from the URDF. TYPE: bool DEFAULT: True