This Python module is an interface to Hang Si’s TetGen C++ software. This module combines speed of C++ with the portability and ease of installation of Python along with integration to PyVista for 3D visualization and analysis. See the TetGen GitHub page for more details on the original creator.
The last update to the original C++ software was on 19 January 2011, but the software remains relevant today. Brief description from Weierstrass Institute Software:
TetGen is a program to generate tetrahedral meshes of any 3D polyhedral domains. TetGen generates exact constrained Delaunay tetrahedralization, boundary conforming Delaunay meshes, and Voronoi partitions.
TetGen provides various features to generate good quality and adaptive tetrahedral meshes suitable for numerical methods, such as finite element or finite volume methods. For more information of TetGen, please take a look at a list of features.
pip install tetgen
From source at GitHub
git clone https://github.com/pyvista/tetgen cd tetgen pip install .
The features of the C++ TetGen software implemented in this module are primarily focused on the tetrahedralization a manifold triangular surface. This basic example demonstrates how to tetrahedralize a manifold surface and plot part of the mesh.
import pyvista as pv import tetgen import numpy as np pv.set_plot_theme('document') sphere = pv.Sphere() tet = tetgen.TetGen(sphere) tet.tetrahedralize(order=1, mindihedral=20, minratio=1.5) grid = tet.grid grid.plot(show_edges=True)
Extract a portion of the sphere’s tetrahedral mesh below the xy plane and plot the mesh quality.
# get cell centroids cells = grid.cells.reshape(-1, 5)[:, 1:] cell_center = grid.points[cells].mean(1) # extract cells below the 0 xy plane mask = cell_center[:, 2] < 0 cell_ind = mask.nonzero() subgrid = grid.extract_cells(cell_ind) # advanced plotting plotter = pv.Plotter() plotter.add_mesh(subgrid, 'lightgrey', lighting=True, show_edges=True) plotter.add_mesh(sphere, 'r', 'wireframe') plotter.add_legend([[' Input Mesh ', 'r'], [' Tesselated Mesh ', 'black']]) plotter.show()
Cell quality scalars can be obtained and plotted with:
cell_qual = subgrid.quality # plot quality subgrid.plot(scalars=cell_qual, stitle='Quality', cmap='bwr', clim=[0,1], flip_scalars=True, show_edges=True,)
Software was originally created by Hang Si based on work published in TetGen, a Delaunay-Based Quality Tetrahedral Mesh Generator.