meshio Formats

Universal mesh format converter for scientific computing.

Installation

pip install meshio

Reading Meshes

import meshio

# Auto-detect format
mesh = meshio.read("model.vtk")
mesh = meshio.read("model.msh")
mesh = meshio.read("model.xdmf")

# Explicit format
mesh = meshio.read("model.dat", file_format="tecplot")

Writing Meshes

import meshio

# Convert formats
mesh = meshio.read("input.msh")
mesh.write("output.vtk")

# Specify format explicitly
mesh.write("output.dat", file_format="abaqus")

Mesh Data Access

import meshio

mesh = meshio.read("model.vtk")

# Points (vertices)
points = mesh.points  # numpy array (n, 3)

# Cells (elements)
for cell_block in mesh.cells:
    print(f"Type: {cell_block.type}, Count: {len(cell_block.data)}")

# Point data (fields at vertices)
for name, data in mesh.point_data.items():
    print(f"Field: {name}, Shape: {data.shape}")

# Cell data (fields at elements)
for name, data in mesh.cell_data.items():
    print(f"Field: {name}")

Creating Meshes

import meshio
import numpy as np

# Define mesh
points = np.array([
    [0.0, 0.0, 0.0],
    [1.0, 0.0, 0.0],
    [1.0, 1.0, 0.0],
    [0.0, 1.0, 0.0],
])

cells = [
    ("triangle", np.array([[0, 1, 2], [0, 2, 3]]))
]

# Create mesh object
mesh = meshio.Mesh(points, cells)

# Add point data
mesh.point_data["temperature"] = np.array([100, 200, 150, 120])

# Add cell data
mesh.cell_data["material"] = [np.array([1, 2])]

mesh.write("output.vtk")

Supported Formats

• VTK: .vtk, .vtu, .pvtu
• Gmsh: .msh
• XDMF: .xdmf
• Exodus: .e, .exo
• Abaqus: .inp
• ANSYS: .ans
• CGNS: .cgns
• DOLFIN: .xml
• STL: .stl
• PLY: .ply
• OBJ: .obj

Command Line

# Convert file
meshio convert input.msh output.vtk

# Show mesh info
meshio info model.vtk

# Compress/decompress
meshio compress mesh.vtu
meshio decompress mesh.vtu