# Clip Volume Widget
# ==================

# If you have a structured dataset like a `pyvista.ImageData` or
# `pyvista.RectilinearGrid`, you can clip it using the
# `pyvista.Plotter.add_volume_clip_plane()` widget to better see the internal
# structure of the dataset.

# Create the Dataset
# ------------------

# Create a dense `pyvista.ImageData` with dimensions `(200, 200,
# 200)` and set the active scalars to distance from the `center` of the grid.
import numpy as np
import pyvista as pv

grid = pv.ImageData(dimensions=(200, 200, 200))
grid['scalars'] = np.linalg.norm(grid.center - grid.points, axis=1)
grid

# Generate the Opacity Array
# --------------------------

# Create a banded opacity array such that our dataset shows "rings" at certain
# values. Have this increase such that higher values (values farther away from
# the center) are more opaque.
opacity = np.zeros(100)
opacity[::10] = np.geomspace(0.01, 0.75, 10)

# Plot a Single Clip Plane Dataset
# --------------------------------

# Plot the volume with a single clip plane.
# Reverse the opacity array such that portions closer to the center are more
# opaque.
pl = pv.Plotter()
pl.add_volume_clip_plane(grid, normal='-x', opacity=opacity[::-1], cmap='magma')
pl.show()

# Plot Multiple Clip Planes
# -------------------------

# Plot the dataset using the `pyvista.Plotter.add_volume_clip_plane()` with
# the output from `pyvista.Plotter.add_volume()` Enable constant
# interaction by setting the `interaction_event` to `'always'`.
# Disable the arrows to make the plot a bit clearer and flip the opacity array.
pl = pv.Plotter()
vol = pl.add_volume(grid, opacity=opacity)
vol.prop.interpolation_type = 'linear'
pl.add_volume_clip_plane(
    vol,
    normal='-x',
    interaction_event='always',
    normal_rotation=False,
)
pl.add_volume_clip_plane(
    vol,
    normal='-y',
    interaction_event='always',
    normal_rotation=False,
)
pl.show()

# ----------------------------------------------------------------------
# Generated by sphinx-examples-as-code https://github.com/pyvista/sphinx-examples-as-code