Basic usage#

This section demonstrates how to use PyVista to reading and plotting 3D data using the pyvista.examples module and external files.

Tip

This section of the tutorial was adopted from the Basic API Usage chapter of the PyVista documentation.

Using Existing Data#

There are two main ways of getting data into PyVista: creating it yourself from scratch or loading the dataset from any one of the compatible file formats. Since we’re just starting out, let’s load a file.

If you have a dataset handy, like a surface model, point cloud, or VTK file, you can use that. If you don’t have something immediately available, PyVista has a variety of files you can download in its pyvista.examples.downloads module.

Here’s a very basic dataset you can download.

from pyvista import examples
dataset = examples.download_saddle_surface()
dataset

PolyData	Information
N Cells	5131
N Points	2669
N Strips	0
X Bounds	-2.001e+01, 2.000e+01
Y Bounds	-6.480e-01, 4.024e+01
Z Bounds	-6.093e-01, 1.513e+01
N Arrays	0

Note how this is a pyvista.PolyData, which is effectively a surface dataset containing points, lines, and/or faces. We can immediately plot this with:

dataset.plot(color='tan')

This is a fairly basic plot. You can change how its plotted by adding parameters as show_edges=True or changing the color by setting color to a different value. All of this is described in PyVista’s API documentation in pyvista.plot(), but for now let’s take a look at another dataset. This one is a volumetric dataset.

dataset = examples.download_frog()
dataset

Header

Data Arrays

UniformGrid	Information
N Cells	31594185
N Points	31960000
X Bounds	0.000e+00, 4.990e+02
Y Bounds	0.000e+00, 4.690e+02
Z Bounds	0.000e+00, 2.025e+02
Dimensions	500, 470, 136
Spacing	1.000e+00, 1.000e+00, 1.500e+00
N Arrays	1

Name	Field	Type	N Comp	Min	Max
MetaImage	Points	uint8	1	0.000e+00	2.540e+02

This is a pyvista.UniformGrid, which is a dataset containing a uniform set of points with consistent spacing. When we plot this dataset, we have the option of enabling volumetric plotting, which plots individual cells based on the content of the data associated with those cells.

dataset.plot(volume=True)