Pyqtgraph’s Scene

PyQtGraph 3D scene definition.

Classes:

Scene3D(inertial_frame, zero_point[, view])

Class for plotting sympy mechanics in pyqtgraph.

class symmeplot.pyqtgraph.scene.Scene3D(inertial_frame: sympy.physics.vector.frame.ReferenceFrame, zero_point: sympy.physics.vector.point.Point, view: GLViewWidget | None = None, **inertial_frame_properties: object)

Bases: SceneBase

Class for plotting sympy mechanics in pyqtgraph.

Parameters:

• inertial_frame (sympy.physics.vector.frame.ReferenceFrame) – The reference frame with respect to which all objects will be oriented.

• origin (sympy.physics.vector.point.Point) – The absolute origin with respect to which all objects will be positioned.

• view (pyqtgraph.opengl.GLViewWidget, optional) – The view in which the scene should be plotted. If None, a new view is created.

• **inertial_frame_properties (dict, optional) – Keyword arguments are parsed to the symmeplot.pyqtgraph.plot_objects.PlotFrame representing the inertial reference frame.

Examples

import sympy.physics.mechanics as me
from symmeplot.pyqtgraph import Scene3D

N = me.ReferenceFrame("N")
A = me.ReferenceFrame("A")
A.orient_axis(N, N.z, 1)
N0 = me.Point("N_0")
v = 0.2 * N.x + 0.2 * N.y + 0.7 * N.z
A0 = N0.locatenew("A_0", v)
scene = Scene3D(N, N0, scale=0.5)
scene.add_vector(v, name="v")
scene.add_frame(A, A0, as_mesh=True)
scene.lambdify_system(())
scene.evaluate_system()
scene.plot()

Methods:

add_body(body, **kwargs)	Add a sympy body to the scene.
add_frame(frame[, origin])	Add a sympy ReferenceFrame to the scene.
add_line(points[, name])	Add a sympy Vector to the scene.
add_plot_object(plot_object)	Add a plot object to the scene.
add_point(point, **kwargs)	Add a sympy Vector to the scene.
add_point_trace(point[, frequency, alpha_decays])	Add a traced point to the scene.
add_vector(vector[, origin])	Add a sympy Vector to the scene.
animate(get_args, frames[, interval])	Animate the scene.
evaluate_system(*args)	Evaluate the system using the function created with lambdify_system.
get_expressions_to_evaluate()	Return a tuple of the necessary expressions for plotting.
get_plot_object(sympy_object)	Return the plot_object based on a sympy object.
lambdify_system(args[, modules, printer, ...])	Lambdify the system.
plot()	Plot all plot objects.
set_visibility(sympy_object, is_visible[, ...])	Hide or show a plot_object based on a sympy_object.
update()	Update the objects on the scene, based on the current values.

Attributes:

artists	Artists used to plot the object.
children	Plot objects.
inertial_frame	The reference frame with respect to which all objects will be oriented.
plot_objects	Plot objects.
values	List of evaluated values for the object's variables.
view	The view in which the scene is plotted.
zero_point	The absolute origin with respect to which all objects will be positioned.

add_body(body: Particle | RigidBody, **kwargs: object) → PlotBase

Add a sympy body to the scene.

Parameters:

• body (sympy.physics.mechanics.rigidbody.RigidBody or sympy.physics.mechanics.particle.Particle) – The body that should be plotted.

• **kwargs (dict, optional) – Kwargs that are parsed to both internally used plot objects.

Returns:

The added plot object.

Return type:

PlotBody

add_frame(frame: ReferenceFrame, origin: Point | Vector | None = None, **kwargs: object) → PlotBase

Add a sympy ReferenceFrame to the scene.

Parameters:

• frame (sympy.physics.vector.frame.ReferenceFrame) – The reference frame that should be plotted.

• origin (sympy.physics.vector.point.Point, sympy.physics.vector.vector.Vector, optional) – The origin of the reference frame. Default is the zero_point.

• **kwargs (dict, optional) – Kwargs that are parsed to plot object.

Returns:

The added plot object.

Return type:

PlotFrame

add_line(points: Iterable[Point | Vector], name: str | None = None, **kwargs: object) → PlotBase

Add a sympy Vector to the scene.

Parameters:

• points (list of sympy.physics.vector.point.Point or sympy.physics.vector.vector.Vector) – The points or vectors through which the line should be plotted.

• name (str, optional) – The name of the line. Default is None.

• **kwargs – Kwargs that are parsed to plot object.

Returns:

The added plot object.

Return type:

PlotLine

add_plot_object(plot_object: PlotBase) → None

Add a plot object to the scene.

Parameters:

plot_object (PlotBase) – The plot object that should be added.

add_point(point: Point | Vector, **kwargs: object) → PlotBase

Add a sympy Vector to the scene.

Parameters:

• point (sympy.physics.vector.point.Point or sympy.physics.vector.vector.Vector) – The point or vector to be plotted as point in space.

• **kwargs – Keyword arguments are parsed to the plot object.

Returns:

The added plot object.

Return type:

PlotPoint

add_point_trace(point: Point | Vector, frequency: int = 1, alpha_decays: Callable[[np.ndarray[np.int64]], np.ndarray[np.float64]] | None = None, **kwargs: object) → PlotBase

Add a traced point to the scene.

Parameters:

• point (sympy.physics.vector.point.Point or sympy.physics.vector.vector.Vector) – The point or vector to be traced in space.

• frequency (int, optional) – Frequency to log the point with. Default is 1 (shows every point).

• alpha_decays (callable, optional) – Function that returns the transparency of a point based on the number of evaluations since it was logged. This input is an array of integers representing the age of each logged point, and the output should be an array of floats between 0 and 1 representing the alpha values. If None, no transparency decay is applied. Default is None. Hint: you can use np.vectorize to vectorize a function for this purpose.

• **kwargs – Keyword arguments are parsed to the plot object.

Returns:

The added plot object.

Return type:

PlotTracedPoint

add_vector(vector: Vector, origin: Point | Vector | None = None, **kwargs: object) → PlotBase

Add a sympy Vector to the scene.

Parameters:

• vector (sympy.physics.vector.vector.Vector) – The vector that should be plotted with respect to the zero_point.

• origin (sympy.physics.vector.point.Point, sympy.physics.vector.vector.Vector, optional) – The origin of the reference frame. Default is the zero_point.

• **kwargs (dict, optional) – Kwargs that are parsed to the plot object.

Returns:

The added plot object.

Return type:

PlotVector

animate(get_args: Callable[[object], tuple], frames: Iterable[object] | int, interval: int = 30) → None

Animate the scene.

Parameters:

• get_args (Callable) – Function that returns the arguments for the evaluate_system method. The function should takes the current frame as input.

• frames (int or iterable) – Number of frames or iterable with frames.

• interval (int, optional) – Time interval between frames in milliseconds. Default is 30.

property artists: tuple[ArtistBase, ...]

Artists used to plot the object.

property children: tuple[PlotBase, ...]

Plot objects.

evaluate_system(*args: object) → None

Evaluate the system using the function created with lambdify_system.

get_expressions_to_evaluate() → tuple

Return a tuple of the necessary expressions for plotting.

get_plot_object(sympy_object: object | str) → PlotBase | None

Return the plot_object based on a sympy object.

Explanation

Return the plot_object based on a provided sympy object. For example ReferenceFrame('N') will give the PlotFrame of that reference frame. If the plot_object has not been added it will return None.

Parameters:

sympy_object (object or str) – SymPy object to search for. If it is a string it will search for the name.

Returns:

Retrieved plot object.

Return type:

PlotBase or None

property inertial_frame: sympy.physics.vector.frame.ReferenceFrame

The reference frame with respect to which all objects will be oriented.

lambdify_system(args, modules=None, printer=None, use_imps=True, dummify=False, cse=True) → Callable

Lambdify the system.

Explanation

Lambdify the system for faster evaluation, when combined with symmeplot.core.scene.SceneBase.evaluate_system(). See sympy.utilities.lambdify.lambdify() for more information.

plot() → None

Plot all plot objects.

property plot_objects: tuple[PlotBase, ...]

Plot objects.

set_visibility(sympy_object: object | str, is_visible: bool, raise_error: bool = True) → None

Hide or show a plot_object based on a sympy_object.

Parameters:

• sympy_object (sympy.physics.vector.point.Point or sympy.physics.vector.vector.Vector or sympy.physics.vector.frame.ReferenceFrame or sympy.physics.mechanics.particle.Particle or sympy.physics.mechanics.rigidbody.RigidBody or str) – SymPy object to show or hide.

• is_visible (bool) – If True show plot_object, otherwise hide plot_object.

• raise_error (bool, optional) – If plot_object not found raise an error. Default is True.

update() → None

Update the objects on the scene, based on the current values.

property values: tuple

List of evaluated values for the object’s variables.

property view: GLViewWidget

The view in which the scene is plotted.

property zero_point: sympy.physics.vector.point.Point

The absolute origin with respect to which all objects will be positioned.