meshRW

meshRW is a lightweight Python library to read/write mesh files for Gmsh and VTK-based workflows.

What it provides

• Read legacy Gmsh meshes (.msh, v2.2).
• Write Gmsh meshes (.msh) with static or transient fields.
• Write legacy VTK (.vtk) and XML VTK (.vtu + .pvd) outputs.
• Export nodal and elemental data, including time-series results.

Installation

pip install meshRW

For contributors (lint + docs tooling):

pip install -e .[dev,docs]

Quick start

Read a Gmsh mesh

from meshRW import msh

mesh = msh.mshReader(filename="input.msh", dim=3)
nodes = mesh.getNodes()
elements = mesh.getElements(dictFormat=True)

Write a VTK/VTU result

from meshRW import vtk2

vtk2.vtkWriter(
    filename="output.vtu",
    nodes=nodes,
    elements=elements,
    fields=[],
)

Writer input model

Writers share the same core data model:

• nodes: array-like (n_nodes, 2|3).
• elements: a dictionary or list of dictionaries with connectivity, type, and optional physgrp.
• fields: list of dictionaries with name, type (nodal/elemental), dim, data, and optional time metadata (nbsteps, steps).

Format notes

• .msh: use meshRW.msh (legacy) or meshRW.msh2 (Gmsh API-backed, version options).
• .vtk: use meshRW.vtk (legacy writer).
• .vtu / .pvd: use meshRW.vtk2 for XML and transient outputs.

Documentation

• Hosted documentation on Read the Docs: meshrw.readthedocs.io
• Project docs index: docs/index.md
• Getting started: docs/getting-started.md
• API overview: docs/api-overview.md
• Format support: docs/format-support.md
• Development guide: docs/development.md

Development and quality

• Tests: pytest meshRW/tests -q
• Lint: ruff check meshRW
• Docs build: sphinx-build -W --keep-going -b html docs docs/_build/html

See CONTRIBUTING.md for the full workflow.

Related projects

• meshio

License

This project is licensed under the MIT License. See LICENSE.