Moving Isovalue

Make an animation of an isovalue through a volumetric dataset

import pyvista as pv
from pyvista import examples
import numpy as np

vol = examples.download_brain()
vol
HeaderData Arrays
UniformGridInformation
N Cells6998400
N Points7109137
X Bounds0.000e+00, 1.800e+02
Y Bounds0.000e+00, 2.160e+02
Z Bounds0.000e+00, 1.800e+02
Dimensions181, 217, 181
Spacing1.000e+00, 1.000e+00, 1.000e+00
N Arrays1
NameFieldTypeN CompMinMax
image_dataPointsuint810.000e+002.550e+02


Now lets make an array of all of the isovalues for which we want to show.

values = np.linspace(5, 150, num=25)

Now let’s create an initial isosurface that we can plot and move

surface = vol.contour([values[0]],)

Precompute the surfaces

surfaces = [vol.contour([v]) for v in values]

Set a single surface as the one being plotted that can be overwritten

surface = surfaces[0].copy()
filename = "isovalue.gif"

plotter = pv.Plotter()
# Open a movie file
plotter.open_gif(filename)
plotter.enable_depth_peeling()

# Add initial mesh
plotter.add_mesh(surface, opacity=0.5, clim=vol.get_data_range())
# Add outline for reference
plotter.add_mesh(vol.outline_corners(), color='k')

print('Orient the view, then press "q" to close window and produce movie')
plotter.camera_position = [
    (392.9783280407326, 556.4341372317185, 235.51220650196404),
    (88.69563012828344, 119.06774369173661, 72.61750326143748),
    (-0.19275936948097383, -0.2218876327549124, 0.9558293278131397)]

# initial render and do NOT close
plotter.show(auto_close=False)

# Run through each frame
for surf in surfaces:
    surface.overwrite(surf)
    plotter.write_frame()  # Write this frame
# Run through backwards
for surf in surfaces[::-1]:
    surface.overwrite(surf)
    plotter.write_frame()  # Write this frame

# Be sure to close the plotter when finished
plotter.close()
isovalue

Out:

Orient the view, then press "q" to close window and produce movie

Total running time of the script: ( 0 minutes 34.534 seconds)

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