README.md

dds-hexmeshing

Semantic data folders (dds) for hexahedral mesh generation

🔄 Changelog • 📖 Documentation

Instead of having:

• a local data folder in each code repo (and a total mess inside each of them),
• to remember the command line interface of each executable (please, don't learn them by heart),
• to include other algorithms in your repo to compare them (adding dependencies and slipping towards enormous repos),

this project make it possible to keep each algorithm small and independent, and offering to the user an object-oriented API on data folders like, for a polycube-based hexahedral mesh generation:

Auto-download the MAMBO dataset:
 ./dds.py run import_MAMBO ~/data

  📂~/data
+   📁B0
+   📁B1
+   ...
+   📁S45

Tetrahedrization of M7 with Gmsh:
 ./dds.py run Gmsh ~/data/M7 characteristic_length_factor=0.2

📂~/data 📂M7 + 📂Gmsh_0.2 + 📄tet.mesh + 📄surface.obj

Hmm, I need a finer mesh...
 ./dds.py run Gmsh ~/data/M7 characteristic_length_factor=0.05

📂~/data 📂M7 📁Gmsh_0.2 + 📂Gmsh_0.05 + 📄tet.mesh + 📄surface.obj

Alright. I wonder what the naive labeling looks like.
 ./dds.py run naive_labeling ~/data/M7/Gmsh_0.05

📂~/data 📂M7 📁Gmsh_0.2 📂Gmsh_0.05 + 📂naive_labeling + 📄surface_labeling.txt 📄tet.mesh 📄surface.obj

Okay, it's not valid. Let me tweak the labeling by hand.
 Sure: ./dds.py run labeling_painter ~/data/M7/Gmsh_0.05

📂~/data 📂M7 📁Gmsh_0.2 📂Gmsh_0.05 📁naive_labeling + 📂labeling_painter + 📄surface_labeling.txt 📄tet.mesh 📄surface.obj

Ho-ho! Can you extract a hex-mesh with libHexEx?
 Indeed I can: ./dds.py run polycube_withHexEx ~/data/M7/Gmsh_0.05/labeling_painter

📂~/data 📂M7 📁Gmsh_0.2 📂Gmsh_0.05 📁naive_labeling 📂labeling_painter + 📂polycube_withHexEx_1.0 + 📄hex.mesh 📄surface_labeling.txt 📄tet.mesh 📄surface.obj

Fantastic!! Can you also apply a global padding? 🥺
 You know I'm just a Python script, right?
 ./dds.py run global_padding ~/data/M7/Gmsh_0.05/labeling_painter/polycube_withHexEx_1.0

📂~/data 📂M7 📁Gmsh_0.2 📂Gmsh_0.05 📁naive_labeling 📂labeling_painter 📂polycube_withHexEx_1.0 + 📂global_padding + 📄hex.mesh 📄hex.mesh 📄surface_labeling.txt 📄tet.mesh 📄surface.obj

File format conversions required by some algorithms are automatic.

Overview of the data subfolder types (boxes) and the wrapped algorithms (arrows):

graph LR
    step(step)
    stl(stl)
    tet-mesh(tet-mesh)
    labeling(labeling)
    hex-mesh(hex-mesh)
    step -- Gmsh --> tet-mesh
    tet-mesh -- naive_labeling --> labeling
    tet-mesh -- labeling_painter --> labeling
    tet-mesh -- graphcut_labeling --> labeling
    tet-mesh -- evocube --> labeling
    tet-mesh -- automatic_polycube --> labeling
    tet-mesh -- HexBox --> hex-mesh
    tet-mesh -- AlgoHex --> hex-mesh
    tet-mesh -- marchinghex --> hex-mesh
    labeling -- polycube_withHexEx --> hex-mesh
    labeling -- robustPolycube --> hex-mesh
    hex-mesh -- global_padding --> hex-mesh
    hex-mesh -- inner_smoothing --> hex-mesh
    stl -- MG-Tetra --> tet-mesh

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Repository structure:

• definitions/paths.yml: links to external binaries
• definitions/data_folder_types/*: definition of the types that data folders can have (tet-mesh, labeling, etc)
• definitions/algorithms/*: definition of the runnable algorithms, wrapping binaries & creating/updating data folders
• dds.py: command-line arguments interpreter, definitions parser & action execution
• img: images displayed in the README