Animation deletes traces

Below is a minimal example, where using a slider to show different traces will delete another trace.

The example plots a grid of points and uses a slider to interactively display selected rows, however, the original grid plot disappears as soon as the slider is moved.

This looks like a bug to me. If it’s not, how can I prevent that trace from disappearing?

import numpy as np
import plotly.graph_objects as go
# generate grid
N = 10
x, y = np.meshgrid(np.linspace(0, 1, N), np.linspace(0, 1, N))
z = np.zeros((N, N))
# plot
fig = go.Figure(
    # all points (THIS DISAPPEARS!)
    data=[go.Scatter3d(x=x.flatten(), y=y.flatten(), z=z.flatten())],
    # single rows animated via slider
    frames=[go.Frame(data=[go.Scatter3d(x=x[i], y=y[i], z=z[i])], name=f"{i}") for i in range(N)],
    layout_sliders=[dict(steps=[dict(method='animate', args=[[f"{k}"]], label=f"{k}") for k in range(N)])])
fig.write_html('plot.html')
fig.show()

Two other weird things (potential bugs), which might be unrelated:

• Setting a marker size on the first trace also changes the marker size of the animated traces. Should that be the case?!
• The interactively opened plot behaves differently from opening the saved html plot (the second one starts playing the animation right away, the first one doesn’t).

I have also posted this in the community forum but without any reactions so far.

Inizia eseguendo l’esempio Python minimo e confronta il risultato interattivo di fig.show() con il plot.html salvato. Analizza i frame dell’animazione e il comportamento dello slider, inclusi il trace della griglia che scompare, la dimensione condivisa dei marker e il diverso comportamento dell’autoplay; il lavoro è completo quando i comportamenti osservati sono spiegati e il bug confermato è corretto senza rompere gli altri trace.