scene

Everything to describe scenes to be simulated.

Subpackages

• conversion
• geometry
  • textures
• sensors
• vector2
  • vector2
  • vector2aux

Package Contents

Classes

AABB	An axis aligned bounding box.
Color	Represents a color in RGBA format.
ControlInterface	Interface for controlling a scene during simulation.
Joint	Base class for all joints.
JointFixed	A joint fixing the rigid bodies together rigidly.
JointHinge	A hinge joint, also known as revolute joint.
MultiBodySystem	A (possibly cyclic) graph of interconnected rigid bodies, joints, and other objects, such as cameras.
Pose	A position and orientation.
RigidBody	A collection of geometries and physics parameters.
Scene	Description of a scene that can be simulated.
SimulationHandler	Base class for handling a simulation, which includes, for example, controlling robots.
SimulationState	Interface for the state of a simulation at certain point.
UUIDKey	Wraps a value and implements __eq__ and __hash__ based purely on id(value).

class AABB

An axis aligned bounding box.

size: pyrr.Vector3

Sizes of the length of the bounding box.

Not half of the box.

class Color

Represents a color in RGBA format.

All values should from 0 to 255.

red: int

green: int

blue: int

alpha: int

to_normalized_rgba_list() → list[float]

Convert to rgba list where each value is between 0 and 1.

Returns:

The list.

to_normalized_rgb_list() → list[float]

Convert to rgb list where each value is between 0 and 1.

Returns:

The list.

class ControlInterface

Bases: abc.ABC

Interface for controlling a scene during simulation.

abstract set_joint_hinge_position_target(joint_hinge: simulation.scene._joint_hinge.JointHinge, position: float) → None

Set the position target of a hinge joint.

Parameters:

• joint_hinge – The hinge to set the position target for.

• position – The position target.

class Joint

Base class for all joints.

property uuid: uuid.UUID

Get the uuid.

Returns:

The uuid.

pose: simulation.scene._pose.Pose

Pose of the joint.

rigid_body1: simulation.scene._rigid_body.RigidBody

The first attached rigid body.

rigid_body2: simulation.scene._rigid_body.RigidBody

The second attached rigid body.

class JointFixed

Bases: simulation.scene._joint.Joint

A joint fixing the rigid bodies together rigidly.

This makes them effectively a single rigid body.

class JointHinge

Bases: simulation.scene._joint.Joint

A hinge joint, also known as revolute joint.

Rotates around a single axis.

axis: pyrr.Vector3

Directional vector the joint rotates about.

range: float

Rotation range of the joint in radians.

How much it can rotate to each side, in radians. So double this is the complete range of motion.

effort: float

Maximum effort the joint can exert, in newton-meter.

velocity: float

Maximum velocity of the joint, in radian per second.

armature: float

Armature of the joint.

This represents the inertia of the motor itself when nothing is attached.

pid_gain_p: float

Proportional gain of the pid position controller.

pid_gain_d: float

Derivative gain of the pid position controller.

class MultiBodySystem

A (possibly cyclic) graph of interconnected rigid bodies, joints, and other objects, such as cameras.

The first rigid body added is considered the root of the system. That is, if the system is static, that rigid body will be static.

property uuid: uuid.UUID

Get the uuid.

Returns:

The uuid.

property root: simulation.scene._rigid_body.RigidBody

Get the root rigid body of this multi-body system.

The root rigid body is the first rigid body that has been added.

Returns:

The root rigid body.

pose: simulation.scene._pose.Pose

Pose of the system.

is_static: bool

Whether the root rigid body is static.

I.e. its root (the first rigid body) is attached to the world and will not move or rotate.

add_rigid_body(rigid_body: simulation.scene._rigid_body.RigidBody) → None

Add a rigid body to the system.

Parameters:

rigid_body – The rigid body to add.

add_joint(joint: simulation.scene._joint.Joint) → None

Add a joint between two rigid bodies.

Parameters:

joint – The joint to add.

has_root() → bool

Check whether a root has been added.

The root rigid body is the first rigid body that has been added, so this is only false if there are zero rigid bodies in this multi-body system.

Returns:

Whether there is a root joint.

get_joints_for_rigid_body(rigid_body: simulation.scene._rigid_body.RigidBody) → list[simulation.scene._joint.Joint]

Get all joints attached to the provided rigid body.

Parameters:

rigid_body – A previously added rigid body.

Returns:

The attached joints.

calculate_aabb() → tuple[pyrr.Vector3, simulation.scene._aabb.AABB]

Calculate the axis-aligned bounding box of this multi-body system when it is in T-pose.

That is, when all joints are at position 0. Only box geometries are currently supported.

Returns:

Position, AABB

Raises:

ValueError – If one of the geometries is not a box.

class Pose

A position and orientation.

position: pyrr.Vector3

Position of the object.

orientation: pyrr.Quaternion

Orientation of the object.

class RigidBody(initial_pose: simulation.scene._pose.Pose, static_friction: float, dynamic_friction: float, geometries: list[simulation.scene.geometry.Geometry])

A collection of geometries and physics parameters.

property uuid: uuid.UUID

Get the uuid.

Returns:

The uuid.

initial_pose: simulation.scene._pose.Pose

static_friction: float

dynamic_friction: float

geometries: list[simulation.scene.geometry.Geometry]

sensors: _AttachedSensors

mass() → float

Get mass of the rigid body.

Returns:

The mass.

center_of_mass() → pyrr.Vector3

Calculate the center of mass in the local reference frame of this rigid body.

If no geometry has mass, the average position of all geometries is returned, unweighted.

Returns:

The center of mass.

inertia_tensor() → pyrr.Matrix33

Calculate the inertia tensor in the local reference frame of this rigid body.

For more details on the inertia calculations, see https://en.wikipedia.org/wiki/List_of_moments_of_inertia.

Returns:

The inertia tensor.

Raises:

ValueError – If one of the geometries is not a box.

class Scene

Description of a scene that can be simulated.

property multi_body_systems: list[simulation.scene._multi_body_system.MultiBodySystem]

Get the multi-body systems in scene.

Do not make changes to this list.

Returns:

The multi-body systems in the scene.

handler: simulation.scene._simulation_handler.SimulationHandler

add_multi_body_system(multi_body_system: simulation.scene._multi_body_system.MultiBodySystem) → None

Add a multi-body system to the scene.

Parameters:

multi_body_system – The multi-body system to add.

class SimulationHandler

Bases: abc.ABC

Base class for handling a simulation, which includes, for example, controlling robots.

abstract handle(state: simulation.scene._simulation_state.SimulationState, control: simulation.scene._control_interface.ControlInterface, dt: float) → None

Handle a simulation frame.

Parameters:

• state – The current state of the simulation.

• control – Interface for setting control targets.

• dt – The time since the last call to this function.

class SimulationState

Bases: abc.ABC

Interface for the state of a simulation at certain point.

abstract get_rigid_body_relative_pose(rigid_body: simulation.scene._rigid_body.RigidBody) → simulation.scene._pose.Pose

Get the pose of a rigid body, relative to its parent multi-body system’s reference frame.

Parameters:

rigid_body – The rigid body to get the pose for.

Returns:

The relative pose.

abstract get_rigid_body_absolute_pose(rigid_body: simulation.scene._rigid_body.RigidBody) → simulation.scene._pose.Pose

Get the pose of a rigid body, relative the global reference frame.

Parameters:

rigid_body – The rigid body to get the pose for.

Returns:

The absolute pose.

abstract get_multi_body_system_pose(multi_body_system: simulation.scene._multi_body_system.MultiBodySystem) → simulation.scene._pose.Pose

Get the pose of a multi-body system, relative to the global reference frame.

Parameters:

multi_body_system – The multi-body system to get the pose for.

Returns:

The relative pose.

abstract get_hinge_joint_position(joint: simulation.scene._joint_hinge.JointHinge) → float

Get the rotational position of a hinge joint.

Parameters:

joint – The joint to get the rotational position for.

Returns:

The rotational position.

abstract get_imu_specific_force(imu_sensor: simulation.scene.sensors.IMUSensor) → pyrr.Vector3

Get the specific force measured an IMU.

Parameters:

imu_sensor – The IMU.

Returns:

The specific force.

abstract get_imu_angular_rate(imu_sensor: simulation.scene.sensors.IMUSensor) → pyrr.Vector3

Get the angular rate measured by am IMU.

Parameters:

imu_sensor – The IMU.

Returns:

The angular rate.

abstract get_camera_view(camera_sensor: simulation.scene.sensors.CameraSensor) → numpy.typing.NDArray[numpy.uint8]

Get the camera view.

Parameters:

camera_sensor – The camera.

Returns:

The view.

class UUIDKey(value: _T)

Bases: Generic[_T]

Wraps a value and implements __eq__ and __hash__ based purely on id(value).

property value: _T

Get the wrapped value.

Returns:

The value.

__eq__(other: object) → bool

Compare with another wrapped value using their ids.

Parameters:

other – The object to compare with.

Returns:

Whether their ids are equal.

Raises:

ValueError – If the other objecgt is not an UUIDKey.

__hash__() → int

Hash this object using its id only.

Returns:

The hash.