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I/O for various mesh formats
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Latest commit 46ebada Jul 19, 2019


I/O for mesh files.

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There are various mesh formats available for representing unstructured meshes. meshio can read and write all of the following and smoothly converts between them:

Install with

pip3 install meshio[all] --user

and simply call

meshio-convert input.msh output.vtu

with any of the supported formats.

In Python, simply do

import meshio

mesh =  # optionally specify file_format
# mesh.points, mesh.cells, ...

to read a mesh. To write, do

points = numpy.array([
    [0.0, 0.0, 0.0],
    [0.0, 1.0, 0.0],
    [0.0, 0.0, 1.0],
cells = {
    "triangle": numpy.array([
        [0, 1, 2]
    # Optionally provide extra data on points, cells, etc.
    # point_data=point_data,
    # cell_data=cell_data,
    # field_data=field_data

or explicitly create a mesh object for writing

mesh = meshio.Mesh(points, cells)
meshio.write("foo.vtk", mesh)

For both input and output, you can optionally specify the exact file_format (in case you would like to enforce ASCII over binary VTK, for example).

Time series

The XDMF format supports time series with a shared mesh. You can write times series data using meshio with

writer = meshio.XdmfTimeSeriesWriter(filename)
writer.write_points_cells(points, cells)
for t in [0.0, 0.1, 0.21]:
    writer.write_data(t, point_data={"phi": data})

and read it with

reader = meshio.XdmfTimeSeriesReader(filename)
points, cells = reader.read_points_cells()
for k in range(reader.num_steps):
    t, point_data, cell_data = reader.read_data(k)


meshio is available from the Python Package Index, so simply do

pip3 install meshio --user

to install.

Additional dependencies (netcdf4, h5py and lxml) are required for some of the output formats and can be pulled in by

pip install -U meshio[all]


To run the meshio unit tests, check out this repository and type



meshio is published under the MIT license.

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