RigidLink

class genesis.engine.entities.rigid_entity.rigid_link.RigidLink(entity: RigidEntity, name: str, idx: int, joint_start: int, n_joints: int, geom_start: int, cell_start: int, vert_start: int, face_start: int, edge_start: int, verts_state_start: int, vgeom_start: int, vvert_start: int, vface_start: int, pos: Buffer | _SupportsArray[dtype[Any]] | _NestedSequence[_SupportsArray[dtype[Any]]] | bool | int | float | complex | str | bytes | _NestedSequence[bool | int | float | complex | str | bytes], quat: Buffer | _SupportsArray[dtype[Any]] | _NestedSequence[_SupportsArray[dtype[Any]]] | bool | int | float | complex | str | bytes | _NestedSequence[bool | int | float | complex | str | bytes], inertial_pos: Buffer | _SupportsArray[dtype[Any]] | _NestedSequence[_SupportsArray[dtype[Any]]] | bool | int | float | complex | str | bytes | _NestedSequence[bool | int | float | complex | str | bytes] | None, inertial_quat: Buffer | _SupportsArray[dtype[Any]] | _NestedSequence[_SupportsArray[dtype[Any]]] | bool | int | float | complex | str | bytes | _NestedSequence[bool | int | float | complex | str | bytes] | None, inertial_i: Buffer | _SupportsArray[dtype[Any]] | _NestedSequence[_SupportsArray[dtype[Any]]] | bool | int | float | complex | str | bytes | _NestedSequence[bool | int | float | complex | str | bytes] | None, inertial_mass: float | None, parent_idx: int, root_idx: int | None, invweight: float | None, visualize_contact: bool)

Bases: RBC

RigidLink class. One RigidEntity consists of multiple RigidLinks, each of which is a rigid body and could consist of multiple RigidGeoms (link.geoms, for collision) and RigidVisGeoms (link.vgeoms for visualization).

get_pos(envs_idx=None)

Get the position of the link in the world frame.

Parameters:

envs_idx (int or array of int, optional) – The indices of the environments to get the position. If None, get the position of all environments. Default is None.

get_quat(envs_idx=None)

Get the quaternion of the link in the world frame.

Parameters:

envs_idx (int or array of int, optional) – The indices of the environments to get the quaternion. If None, get the quaternion of all environments. Default is None.

get_vel(envs_idx=None) → Tensor

Get the linear velocity of the link in the world frame.

Parameters:

envs_idx (int or array of int, optional) – The indices of the environments to get the linear velocity. If None, get the linear velocity of all environments. Default is None.

get_ang(envs_idx=None) → Tensor

Get the angular velocity of the link in the world frame.

Parameters:

envs_idx (int or array of int, optional) – The indices of the environments to get the angular velocity. If None, get the angular velocity of all environments. Default is None.

get_verts()

Get the vertices of the link’s collision body (concatenation of all link.geoms) in the world frame.

get_vverts()

Get the vertices of the link’s visualization body (concatenation of all link.vgeoms) in the world frame.

get_AABB()

Get the axis-aligned bounding box (AABB) of the link’s collision body (concatenation of all link.geoms) in the world frame.

get_vAABB()

Get the axis-aligned bounding box (AABB) of the link’s visual body (concatenation of all link.vgeoms) in the world frame.

set_mass(mass)

Set the mass of the link.

get_mass()

Get the mass of the link.

set_friction(friction)

Set the friction of all the link’s geoms.

property uid

The unique ID of the link.

property name: str

The name of the link.

property entity: RigidEntity

The entity that the link belongs to.

property solver: RigidSolver

The solver that the link belongs to.

property visualize_contact: bool

Whether to visualize the contact of the link.

property joints: list['Joint']

The sequence of joints that connects the link to its parent link.

property n_joints

Number of the joints that connects the link to its parent link.

property joint_start

The start index of the link’s joints in the RigidSolver.

property joint_end

The end index of the link’s joints in the RigidSolver.

property n_dofs

The number of degrees of freedom (DOFs) of the entity.

property dof_start

The index of the link’s first degree of freedom (DOF) in the scene.

property dof_end

The index of the link’s last degree of freedom (DOF) in the scene plus one.

property n_qs

Returns the number of q variables of the link.

property q_start

Returns the starting index of the q variables of the link in the rigid solver.

property q_end

Returns the last index of the q variables of the link in the rigid solver plus one.

property idx

The global index of the link in the RigidSolver.

property parent_idx

The global index of the link’s parent link in the RigidSolver. If the link is the root link, return -1.

property root_idx

The global index of the link’s root link in the RigidSolver.

property child_idxs

The global indices of the link’s child links in the RigidSolver.

property idx_local

The local index of the link in the entity.

property parent_idx_local

The local index of the link’s parent link in the entity. If the link is the root link, return -1.

property child_idxs_local

The local indices of the link’s child links in the entity.

property is_leaf

Whether the link is a leaf link (i.e., has no child links).

property invweight

The invweight of the link.

property pos: Buffer | _SupportsArray[dtype[Any]] | _NestedSequence[_SupportsArray[dtype[Any]]] | bool | int | float | complex | str | bytes | _NestedSequence[bool | int | float | complex | str | bytes]

The initial position of the link. For real-time position, use link.get_pos().

property quat: Buffer | _SupportsArray[dtype[Any]] | _NestedSequence[_SupportsArray[dtype[Any]]] | bool | int | float | complex | str | bytes | _NestedSequence[bool | int | float | complex | str | bytes]

The initial quaternion of the link. For real-time quaternion, use link.get_quat().

property inertial_pos: Buffer | _SupportsArray[dtype[Any]] | _NestedSequence[_SupportsArray[dtype[Any]]] | bool | int | float | complex | str | bytes | _NestedSequence[bool | int | float | complex | str | bytes] | None

The initial position of the link’s inertial frame.

property inertial_quat: Buffer | _SupportsArray[dtype[Any]] | _NestedSequence[_SupportsArray[dtype[Any]]] | bool | int | float | complex | str | bytes | _NestedSequence[bool | int | float | complex | str | bytes] | None

The initial quaternion of the link’s inertial frame.

property inertial_mass: float | None

The initial mass of the link.

property inertial_i: Buffer | _SupportsArray[dtype[Any]] | _NestedSequence[_SupportsArray[dtype[Any]]] | bool | int | float | complex | str | bytes | _NestedSequence[bool | int | float | complex | str | bytes] | None

The inerial matrix of the link.

property geoms: list[genesis.engine.entities.rigid_entity.rigid_geom.RigidGeom]

The list of the link’s collision geometries (RigidGeom).

property vgeoms: list[genesis.engine.entities.rigid_entity.rigid_geom.RigidVisGeom]

The list of the link’s visualization geometries (RigidVisGeom).

property n_geoms: int

Number of the link’s collision geometries.

property geom_start: int

The start index of the link’s collision geometries in the RigidSolver.

property geom_end: int

The end index of the link’s collision geometries in the RigidSolver.

property n_vgeoms: int

Number of the link’s visualization geometries (vgeom).

property vgeom_start: int

The start index of the link’s vgeom in the RigidSolver.

property vgeom_end: int

The end index of the link’s vgeom in the RigidSolver.

property n_cells

Number of sdf cells of all the link’s geoms.

property n_verts: int

Number of vertices of all the link’s geoms.

property n_vverts: int

Number of vertices of all the link’s vgeoms.

property n_faces: int

Number of faces of all the link’s geoms.

property n_vfaces: int

Number of faces of all the link’s vgeoms.

property n_edges: int

Number of edges of all the link’s geoms.

property is_built: bool

Whether the entity the link belongs to is built.

property is_free

Whether the entity the link belongs to is free.

property pose: Pose

Return the current pose of the link (note, this is not necessarily the same as the principal axes frame).