pyvista_isosurface_example.py

import pyvista as pv
import numpy as np

arr = np.random.rand(40, 72, 144)

grid = pv.UniformGrid()

grid.dimensions = np.array(arr.shape) + 1

grid.origin = (0, 0, 0)  # The bottom left corner of the data set
grid.spacing = (1, 1, 1)  # These are the cell sizes along each axis

grid.cell_arrays["values"] = arr.flatten(order="F")  # Flatten the array!

nodal = grid.cell_data_to_point_data()
# geom = nodal.extract_geometry()

contours = nodal.contour(isosurfaces=[0.2, 0.4, 0.9])
contours.plot(cmap='Spectral')

plotter = pv.Plotter()  # instantiate the plotter
plotter.add_mesh(contours)    # add a dataset to the scene
plotter.show()     # show the rendering window