Animation¶

Movements of devices and other objects within simulations may be described by Trajectories, which model the veloctiy, position and orientation of the object as a function of time. Generally, objects that may be animated within a simulation should inherit from the Moveable class, which exposes the trajectory property. The currently available trajectory types are:

Trajectory Types¶
Type	Description
`StaticTrajectory`	A trajectory that does not change over time.
`LinearTrajectory`	A trajectory that moves in a straight line at a constant velocity.

The following example demonstrates how to assign a linear trajectory to a device within a simulation and plot the scenario:

# Create a new simulation featuring two devices
simulation = Simulation()
device_alpha = simulation.new_device()
device_beta = simulation.new_device()

# Assign each device a linear trajectory
device_alpha.trajectory = LinearTrajectory(
    initial_pose=Transformation.From_Translation(np.array([0, 0, 20])),
    final_pose=Transformation.From_Translation(np.array([0, 100, 5])),
    duration=60,
)
device_beta.trajectory = LinearTrajectory(
    initial_pose=Transformation.From_Translation(np.array([100, 100, 0])),
    final_pose=Transformation.From_Translation(np.array([0, 0, 0])),
    duration=60,
)

# Visualize the trajectories
simulation.scenario.visualize()
plt.show()

class Trajectory[source]¶

Bases: ABC

Base class for motion trajectories of moveable objects within simulation scenarios.

lookat(target, up=array([0., 1., 0.]))[source]¶

Set a target to look at and track.

Parameters:

target (Trajectory) – Target trajectory.
up (numpy.ndarray) – Up/sky/head/ceiling global unit vector. Defaults to [0., 1., 0.].

Return type:

None

lookat_disable()[source]¶

Return type:: None

lookat_enable()[source]¶

Return type:: None

sample(timestamp)[source]¶

Sample the trajectory at a given point in time.

Parameters:: timestamp (float) – Time at which to sample the trajectory in seconds.
Return type:: TrajectorySample

Returns: A sample of the trajectory.

abstract sample_orientation(timestamp)[source]¶

Sample the trajectory’s orientation. Does not consider lookat.

Parameters:: timestamp (float) – Time at which to sample the trajectory in seconds.
Return type:: ndarray

Returns: A sample of the trajectory’s orientation matrix (matrix (3, 3) of float).

abstract sample_translation(timestamp)[source]¶

Sample the trajectory’s translation.

Parameters:: timestamp (float) – Time at which to sample the trajectory in seconds.
Return type:: ndarray

Returns: A sample of the trajectory’s translation (vector (3,) of floats).

abstract sample_velocity(timestamp)[source]¶

Sample the trajectory’s velocity.

Parameters:: timestamp (float) – Time at which to sample the trajectory in seconds.
Return type:: ndarray

Returns: A sample of the trajectory’s velocity (vector (3,) of floats).

abstract property max_timestamp: float¶

Maximum timestamp of the trajectory in seconds.

For times greater than this value the represented object’s pose is assumed to be constant.

class StaticTrajectory(pose=None, velocity=None)[source]¶

Bases: Serializable, Trajectory

A helper class generating a static trajectory.

sample(timestamp)[source]¶

Sample the trajectory at a given point in time.

Parameters:: timestamp (float) – Time at which to sample the trajectory in seconds.
Return type:: TrajectorySample

Returns: A sample of the trajectory.

sample_orientation(timestamp)[source]¶

Sample the trajectory’s orientation. Does not consider lookat.

Parameters:: timestamp (float) – Time at which to sample the trajectory in seconds.
Return type:: ndarray

Returns: A sample of the trajectory’s orientation matrix (matrix (3, 3) of float).

sample_translation(timestamp)[source]¶

Sample the trajectory’s translation.

Parameters:: timestamp (float) – Time at which to sample the trajectory in seconds.
Return type:: ndarray

Returns: A sample of the trajectory’s translation (vector (3,) of floats).

sample_velocity(timestamp)[source]¶

Sample the trajectory’s velocity.

Parameters:: timestamp (float) – Time at which to sample the trajectory in seconds.
Return type:: ndarray

Returns: A sample of the trajectory’s velocity (vector (3,) of floats).

property max_timestamp: float¶

Maximum timestamp of the trajectory in seconds.

For times greater than this value the represented object’s pose is assumed to be constant.

property pose: Transformation¶: Static pose of the object.

property velocity: ndarray¶: Static velocity of the object.

class LinearTrajectory(initial_pose, final_pose, duration, start=0.0)[source]¶

Bases: Trajectory

A helper class generating a linear trajectory between two poses.

sample_orientation(timestamp)[source]¶

Sample the trajectory’s orientation. Does not consider lookat.

Parameters:: timestamp (float) – Time at which to sample the trajectory in seconds.
Return type:: ndarray

Returns: A sample of the trajectory’s orientation matrix (matrix (3, 3) of float).

sample_translation(timestamp)[source]¶

Sample the trajectory’s translation.

Parameters:: timestamp (float) – Time at which to sample the trajectory in seconds.
Return type:: ndarray

Returns: A sample of the trajectory’s translation (vector (3,) of floats).

sample_velocity(timestamp)[source]¶

Sample the trajectory’s velocity.

Parameters:: timestamp (float) – Time at which to sample the trajectory in seconds.
Return type:: ndarray

Returns: A sample of the trajectory’s velocity (vector (3,) of floats).

property max_timestamp: float¶

Maximum timestamp of the trajectory in seconds.

For times greater than this value the represented object’s pose is assumed to be constant.

class Moveable(trajectory)[source]¶

Bases: object

Base class of moveable objects within simulation scenarios.

Parameters:: trajectory (Trajectory, optional) – Trajectory this object is following. If not provided, the object is assumed to be static.

property max_trajectory_timestamp: float¶: Maximum timestamp of this object’s motion trajectory.

property trajectory: Trajectory¶: Motion trajectory this object is following.

class TrajectorySample(timestamp, pose, velocity)[source]¶

Bases: object

Dataclass for a single pose sample within a trajectory.

Parameters:

timestamp (float) – Time at which the trajectory was sampled in seconds.
pose (Timestamp) – Pose of the object at the given time.
velocity (numpy.ndarray) – Velocity of the object at the given time.

property pose: Transformation¶: Pose of the object at the given time.

property timestamp: float¶: Time at which the trajectory was sampled in seconds.

property velocity: ndarray¶: Velocity of the object at the given time.