3D Plane Widget

A draggable axis-aligned plane in a 3-D panel, rendered as a translucent quad spanning the panel’s bounds. Drag it in the browser to slide it along its normal — ideal as a slice selector through a volume or point cloud. Add it with plot.add_widget("plane", axis=..., position=...).

import numpy as np
import anyplotlib as apl

A point cloud to slice

A Gaussian blob of points; the plane widget will pick out a z-slab.

rng = np.random.default_rng(0)
n = 4000
pts = rng.normal(0, 8, size=(n, 3)) + 24    # centred in a 0..48 box
xs, ys, zs = pts[:, 0], pts[:, 1], pts[:, 2]

fig, ax = apl.subplots(1, 1, figsize=(520, 500))
cloud = ax.scatter3d(xs, ys, zs, color="#4fc3f7", point_size=3,
                     x_label="x", y_label="y", z_label="z")

plane = cloud.add_widget("plane", axis="z", position=24,
                         color="#40c4ff", alpha=0.15)

fig

Read the slice position on drag

pointer_move fires as the plane slides; plane.position is the current location along its normal. You can also move it from Python with plane.set(position=...).

@plane.add_event_handler("pointer_move")
def _on_drag(event):
    print("z-slice at", round(plane.position, 1))


fig.set_help("Drag the blue plane along z to move the slice.")

fig  # Interactive

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