Note
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Creating a Uniform Grid#
Create a simple uniform grid from a 3D NumPy array of values.
import numpy as np
import pyvista as pv
Take a 3D NumPy array of data values that holds some spatial data where each
axis corresponds to the XYZ cartesian axes. This example will create a
pyvista.UniformGrid
object that will hold the spatial reference for
a 3D grid which a 3D NumPy array of values can be plotted against.
Create the 3D NumPy array of spatially referenced data. This is spatially referenced such that the grid is 20 by 5 by 10 (nx by ny by nz)
values = np.linspace(0, 10, 1000).reshape((20, 5, 10))
values.shape
Create the PyVista object
grid = pv.UniformGrid()
- Set the grid dimensions: shape + 1 because we want to inject our values on
the CELL data
grid.dimensions = np.array(values.shape) + 1
Edit the spatial reference
grid.origin = (100, 33, 55.6) # The bottom left corner of the data set
grid.spacing = (1, 5, 2) # These are the cell sizes along each axis
Add the data values to the cell data
grid.cell_data["values"] = values.flatten(order="F") # Flatten the array!
grid
Now plot the grid!
grid.plot(show_edges=True)
Don’t like cell data? You could also add the NumPy array to the point data of
a pyvista.UniformGrid
. Take note of the subtle difference when
setting the grid dimensions upon initialization.
# Create the 3D NumPy array of spatially referenced data
# This is spatially referenced such that the grid is 20 by 5 by 10
# (nx by ny by nz)
values = np.linspace(0, 10, 1000).reshape((20, 5, 10))
values.shape
Create the PyVista object and set the same attributes like above
grid = pv.UniformGrid()
# Set the grid dimensions: shape because we want to inject our values on the
# POINT data
grid.dimensions = values.shape
# Edit the spatial reference
grid.origin = (100, 33, 55.6) # The bottom left corner of the data set
grid.spacing = (1, 5, 2) # These are the cell sizes along each axis
Add the data values to the cell data
grid.point_data["values"] = values.flatten(order="F") # Flatten the array!
grid
Now plot the grid!
grid.plot(show_edges=True)
Exercise#
Now create your own pyvista.UniformGrid
from a 3D NumPy array!
help(pv.UniformGrid)
Here are some example 3D data using random data. Feel free to use your own 3D numpy array here!
arr = np.random.random((100, 100, 100))
arr.shape
Create the pyvista.UniformGrid
Hint, you will likely need to ravel
the array with F-ordering:
arr.ravel(order="F")
vol = pv.UniformGrid()
# Set attributes and data
...
vol.plot()
Example#
Here are some examples of this kind of data in PyVista!
See the PyVista documentation for further details on Volume Rendering
from pyvista import examples
vol = examples.download_knee_full()
p = pv.Plotter()
p.add_volume(vol, cmap="bone", opacity="sigmoid")
p.show()
vol = pv.Wavelet()
vol.plot(volume=True)
Total running time of the script: ( 0 minutes 0.000 seconds)