PyMeshGen

中文说明 · Packaging Guide

PyMeshGen is an open-source Python project for unstructured mesh generation aimed at CFD/FEA preprocessing and algorithm research. The actively maintained runtime focuses on 2D workflows built around Fluent .cas boundary input, quadtree sizing, boundary-layer growth, advancing-front meshing, and a Delaunay pipeline with Bowyer-Watson and Triangle backends.

Highlights

• Fluent .cas-driven boundary import for meshing workflows
• VTK and STL import/export support
• PyQt5 GUI and command-line entry points
• Boundary-layer generation plus interior triangular and hybrid tri/quad meshing
• Quadtree-based sizing field and post-meshing optimization
• Experimental neural-network and reinforcement-learning smoothing modules under neural/

Requirements

• Python 3.8+
• Core runtime dependencies:

pip install -r requirements.txt

Optional heavyweight dependencies are split out:

pip install -r requirements-optional.txt

Some optional workflows, especially geometry import/export and neural/ML smoothing, rely on packages such as pythonocc-core, torch, torch-geometric, stable-baselines3, and trimesh.

Installation

PyPI (preferred after publication)

pip install pymeshgen

Optional extras:

pip install "pymeshgen[ml]"
pip install "pymeshgen[occ]"

pythonocc-core may be easier to install via conda-forge on some platforms.

Available entry points after installation:

pymeshgen --case ".\config\30p30n.json"
pymeshgen-gui

Local development

pip install -e .

For full local feature coverage:

pip install -r requirements.txt
pip install -r requirements-optional.txt

Quick start

Command line

python PyMeshGen.py --case ".\config\30p30n.json"

If --case is omitted, Parameters falls back to config\main.json, which points to the active case JSON.

GUI

python start_gui.py

The GUI bootstraps project paths automatically and also adds 3rd_party\meshio\src to sys.path for bundled meshio compatibility.

Library usage

fromdata_structure.parametersimportParametersfromPyMeshGenimportPyMeshGenparams=Parameters("FROM_CASE_JSON", r".\config\30p30n.json")
mesh=PyMeshGen(params)

Configuration model

Case JSON files live under config/ and typically define:

• input_file / output_file
• mesh_type
• delaunay_backend
• triangle_point_strategy
• global sizing / visualization options
• parts, where each part must provide at least part_name

Common part-level options include max_size, PRISM_SWITCH, first_height, growth_rate, max_layers, full_layers, and multi_direction.

Meshing pipelines

mesh_type	Pipeline
1, 2	Triangular mesh generation through the advancing-front pipeline
3	Hybrid tri/quad generation; triangle_to_quad_method == "q_morph" uses a triangle-first path
4	Delaunay triangulation through delaunay.create_bowyer_watson_mesh()

Notes for mesh_type == 4:

• delaunay_backend defaults to bowyer_watson
• triangle_point_strategy defaults to equilateral
• when boundary layers are enabled, the effective interior backend is forced to triangle to improve robustness near layered fronts

Project structure

Path	Responsibility
PyMeshGen.py	CLI entry and lightweight library wrapper
start_gui.py	GUI launcher
core.py	Main orchestration pipeline
data_structure/	Parameters, fronts, cells, and Unstructured_Grid
meshsize/	Quadtree sizing-field construction
adfront2/	Boundary-layer and advancing-front interior generation
delaunay/	Bowyer-Watson core, Triangle backend, validation, and postprocess helpers
fileIO/	CAS/VTK/STL/OCC input-output utilities
gui/	PyQt5 GUI modules
optimize/	Mesh optimization and smoothing
unittests/	Regression and unit tests

Testing

Run the existing repository test entry points:

cd unittests
python run_tests.py
python run_quick_tests.py

Run a focused unittest target from the repository root when working on Delaunay or boundary-layer logic:

python -m unittest unittests.test_bowyer_watson.TestBowyerWatsonJSONConfig.test_anw_bowyer_watson

Documentation

• Chinese overview: README_zh.md
• Packaging and release workflow: README_PACKAGING.md
• Delaunay design notes: docs/design/Delaunay模块详细设计.md
• GUI design notes: docs/design/README_GUI module.md
• Model tree notes: docs/design/README_model tree.md

Packaging

PyMeshGen now prioritizes Python package distribution through PyPI.

For standard Python source and wheel builds:

python -m pip install build
python -m build

For PyPI publishing and release workflow details, see README_PACKAGING.md. Optional Windows desktop packaging tools now live under packaging/windows/.

License

PyMeshGen is distributed under GPLv2+. See LICENSE.txt.

Contact

• Project initiator: cfd_dev cfd_dev@126.com