import panel as pn
pn.extension('vtk')

import numpy as np

data_matrix = np.zeros([75, 75, 75], dtype=np.uint8)
data_matrix[0:35, 0:35, 0:35] = 50
data_matrix[25:55, 25:55, 25:55] = 100
data_matrix[45:74, 45:74, 45:74] = 150

pn.pane.VTKVolume(data_matrix, width=800, height=600, spacing=(3,2,1), interpolation='nearest', edge_gradient=0, sampling=0)

import pyvista as pv
from pyvista import examples

# Download a volumetric dataset
vol = examples.download_head()
volume = pn.pane.VTKVolume(vol, height=600, sizing_mode='stretch_width', display_slices=True)
volume

pn.Row(volume.controls(jslink=True), volume)