pytetwild

pytetwild is a Python library for mesh tetrahedralization. It is a Python wrapper around the efficient C++ library for tetrahedral meshing provided by fTetWild.

Installation

We have pre-built wheels for Python 3.8 - Python 3.12 for Windows and Linux x64.

The recommended way to install pytetwild is via PyPI:

pip install pytetwild

You can also clone the repository and install it from source, but since there's C++ involved, the build is a bit more complicated. See CONTRIBUTING.md for more details.

Usage

To tetrahedralize a surface mesh from PyVista:

import pyvista as pv
import pytetwild

# Load or create a PyVista PolyData surface mesh
# Here, we'll create a simple sphere mesh as an example
surface_mesh = pv.Icosphere(nsub=2)

# Convert the surface mesh to a tetrahedral mesh. For this example let's
# use a coarse mesh
tetrahedral_mesh = pytetwild.tetrahedralize_pv(surface_mesh, edge_length_fac=1)

# Visualize the tetrahedral mesh in an "exploded" view
tetrahedral_mesh.explode(1).plot(show_edges=True)

You can also work with raw arrays. Here's a simple cube that we turn into tetrahedra.

import numpy as np

# Define vertices of the cube
vertices = np.array([
    [0, 0, 0],  # Vertex 0
    [1, 0, 0],  # Vertex 1
    [1, 1, 0],  # Vertex 2
    [0, 1, 0],  # Vertex 3
    [0, 0, 1],  # Vertex 4
    [1, 0, 1],  # Vertex 5
    [1, 1, 1],  # Vertex 6
    [0, 1, 1]   # Vertex 7
])

# Define faces using vertex indices
# Each face is a rectangle (also accepts triangles)
faces = np.array([
    [0, 1, 2, 3],  # Front face
    [1, 5, 6, 2],  # Right face
    [5, 4, 7, 6],  # Back face
    [4, 0, 3, 7],  # Left face
    [4, 5, 1, 0],  # Bottom face
    [3, 2, 6, 7]   # Top face
])
v_out, tetra = pytetwild.tetrahedralize(vertices, faces, optimize=False)

Usage - Options

We've surfaced a handful of parameters to each of our interfaces tetrahedralize and tetrahedralize_pv. Here are the optional parameters.

Additional Parameters
---------------------
edge_length_fac : float, default: 0.05
    Tetrahedral edge length as a function of bounding box diagional. The
    default ideal edge length is bb/20 (bounding box divided by 20).
optimize : bool
    Improve the minimum scaled Jacobean for each cell. This leads to higher
    cell quality at the expense of computation time.

License and Acknowledgments

This project relies on fTetWild and credits go to the original authors for their efficient C++ library for tetrahedral meshing. That work is licensed under the Mozilla Public License v2.0.

The work in this repository is also licensed under the Mozilla Public License v2.0.

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