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(examples-vis-animations)=

# Animations

Magpylib can display the motion of objects along paths in the form of animations.

```{hint}
1. Animations work best with the [plotly backend](guide-graphic-backends).

2. If your browser window opens, but your animation does not load, reload the page (ctrl+r in chrome).

3. Avoid rendering too many frames.
```

Detailed information about how to tune animations can be found in the [graphics documentation](guide-graphic-animations).

## Simple Animations

Animations are created with `show` by setting `animation=True`. It is also possible to hand over the animation time with this kwarg.

```{code-cell} ipython3
import numpy as np
import magpylib as magpy

# Define magnet with path
magnet = magpy.magnet.Cylinder(
    polarization=(1, 0, 0),
    dimension=(2, 1),
    position=(4,0,0),
    style_label="magnet",
)
magnet.rotate_from_angax(angle=np.linspace(0, 300, 40), start=0, axis="z", anchor=0)

# Define sensor with path
sensor = magpy.Sensor(
    pixel=[(-.2, 0, 0), (.2, 0, 0)],
    position = np.linspace((0, 0, -3), (0, 0, 3), 40),
    style_label="sensor",
)

# Display as animation - prefers plotly backend
magpy.show(sensor, magnet, animation=True, backend='plotly')
```

(examples-vis-animated-subplots)=

## Animated Subplots

[Subplots](examples-vis-subplots) are a powerful tool to see the field along a path while viewing the 3D models at the same time. This is specifically illustrative as an animation where the field at the respective path position is indicated by a marker.

```{code-cell} ipython3
# Continuation from above - ensure previous code is executed

magpy.show(
    dict(objects=[magnet, sensor], output=["Bx", "By", "Bz"], col=1),
    dict(objects=[magnet, sensor], output="model3d", col=2),
    backend='plotly',
    animation=True,
)
```

It is also possible to use the [show_context](guide-graphics-show_context) context manager.

```{code-cell} ipython3
# Continuation from above - ensure previous code is executed

with magpy.show_context([magnet, sensor], backend='plotly', animation=True) as sc:
    sc.show(output="Bx", col=1, row=1)
    sc.show(output="By", col=1, row=2)
    sc.show(output="Bz", col=2, row=1)
    sc.show(output="model3d", col=2, row=2)
```