---
id: meshioplusplus
version: "10.0.0"
license: The MIT License (MIT) Copyright (c) 2015-2021 Nico Schlömer et al. Copyright (c) 2026 Vicente Mataix Ferrándiz Permission is hereby granted, free of charge, to any person obtaining a copy of this… (full text in the JSON record)
license_treatment: permissive
maintenance: active
---

# meshioplusplus — meshio++: I/O for many mesh formats (C++20 core + Python bindings)

License: permissive · Maintenance: active · Downloads: 83.8K/mo

## What it is and what it does

meshioplusplus is a mesh file I/O library that reads and writes unstructured mesh data in dozens of scientific and engineering formats—including STL, VTK, Gmsh, CGNS, Exodus, Nastran, OpenFOAM, and many others. It provides seamless conversion between formats and includes a command-line tool for mesh manipulation (merge, transform, refine, partition, interpolate, slice, and more). The package ships a C++20 core built with pybind11 and scikit-build-core that achieves zero-copy numpy integration at the I/O boundary, with optional HDF5 and netCDF acceleration and a selectable parallel backend (OpenMP, STL+TBB, or sequential by default). Every format also has a pure-Python fallback, so behavior and file compatibility are identical whether or not native libraries are present.

The library is designed for researchers and engineers working with finite element meshes, computational fluid dynamics, and other simulation workflows. It depends on numpy for array handling, rich for terminal output, and importlib_metadata for version introspection. Pre-built wheels are available for modern Python versions (3.9–3.12) across macOS, Linux, and Windows, making installation straightforward for most users.

Use it for:

- Convert mesh files between incompatible formats (e.g., Gmsh to VTK) in a simulation pipeline.
- Load mesh data from scientific solvers into Python for post-processing and visualization.
- Merge, refine, or partition large meshes using the command-line interface without writing custom code.
- Transfer field data (temperature, pressure, etc.) across different mesh representations.
- Generate signed distance fields or isosurfaces from mesh geometry for level-set methods.

## Worth the install?

AI-flagged interpretation of the facts above — verify before relying.

meshioplusplus reads and writes mesh files in dozens of formats (STL, VTK, Gmsh, CGNS, Exodus, and many others) and converts between them, with a C++20 core that provides zero-copy numpy integration at the I/O boundary.

Yes, if you work with mesh files in scientific computing or engineering. The library supports an extensive range of formats, integrates cleanly with numpy workflows, and offers both programmatic and CLI access. Medium install friction is offset by pre-built wheels and active maintenance. No known vulnerabilities and permissive MIT licensing remove barriers to adoption.

## Install

pip install meshioplusplus
uv add meshioplusplus
poetry add meshioplusplus

## Installing meshioplusplus

Before you install: Medium install friction due to compiled C++20 bindings, but pre-built wheels cover Python 3.9–3.12 on macOS (arm64, x86_64), Linux (aarch64, x86_64), and Windows (amd64). Active maintenance with a release 8 days ago.

License in practice: MIT license (permissive) allows commercial and private use with attribution. No restrictions on modification or redistribution.

Quickstart:

pip install meshioplusplus

import meshioplusplus as mio

mesh = mio.read('input.msh')
mio.write('output.vtk', mesh)

Requires Python 3.8 or later. Optional dependencies (HDF5, netCDF, Kokkos) unlock format acceleration but are not required for basic I/O.

Verify before relying:

- Performance characteristics and memory overhead compared to direct C++ usage or other mesh libraries.
- Completeness of pure-Python fallback implementations for all supported formats.
- Stability and API compatibility guarantees across minor versions.

## Package facts

- License: The MIT License (MIT) Copyright (c) 2015-2021 Nico Schlömer et al. Copyright (c) 2026 Vicente Mataix Ferrándiz Permission is hereby granted, free of charge, to any person obtaining a copy of this… (full text in the JSON record) (permissive)
- Python support: supports_current
- Install friction: medium
- Maintenance: active
- Downloads: 83.8K/month (top 15,000 on PyPI)
- Known vulnerabilities: none known

## Tags

mesh file format conversion, read write mesh files, STL VTK Gmsh I/O, unstructured mesh I/O, mesh format translator, finite element mesh tools, mesh file reader writer, mesh-io, scientific-computing, file-format-conversion

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