Parallel Files

The VTK library supports parallel file formats. Reading meshes broken up into several files is natively supported by VTK and PyVista.

from __future__ import annotations

import os
from pathlib import Path

import pyvista as pv
from pyvista import examples

Let’s go ahead and download the sample dataset containing an pyvista.UnstructuredGrid broken up into several files.

Let’s inspect where this downloaded our dataset by setting load=False and looking at the directory containing the file we downloaded.

filename = examples.download_blood_vessels(load=False)
path = str(Path(filename).parent)
os.listdir(path)

['T0000000500.pvtu', 'T0000000500']

os.listdir(str(Path(path) / "T0000000500"))

['000.vtu', '003.vtu', '001.vtu', '002.vtu']

Note that a .pvtu file is available alongside a directory. This directory contains all the parallel files or pieces that make the whole mesh. We can simply read the .pvtu file and VTK will handle putting the mesh together. In PyVista, this is accomplished through pyvista.read().

mesh = pv.read(filename)
mesh

Header	Data Arrays
UnstructuredGrid Information N Cells 39353 N Points 48823 X Bounds 5.300e+01, 1.210e+02 Y Bounds 5.000e+01, 9.700e+01 Z Bounds 6.400e+01, 1.820e+02 N Arrays 5	Name Field Type N Comp Min Max node_value Points int32 1 0.000e+00 3.000e+00 simerr_type Points int32 1 0.000e+00 3.000e+00 density Cells float32 1 2.203e-01 5.232e-01 velocity Cells float32 3 -3.607e-01 8.989e-02 shearstress Cells float32 1 6.160e-05 1.726e-02

Plot the pieced together mesh

mesh.plot(scalars="node_value", categories=True)

Static Scene

Interactive Scene

mesh.plot(scalars="density")

Static Scene

Interactive Scene