Nightmare of polycubes

(Very) challenging 3D shapes for polycube-based hex-meshing

Files

All models were designed with the Shaper module of the open-source SALOME platform. For each of them, you can download the study (.hdf) and the exported Python script, STEP, B-Rep and STL files.

How to load a .hdf study file in SALOME?

In the menu bar, click on "File" > "Open", select the .hdf file, then open the Shaper module.

How to load a .py Shaper script in SALOME?

First, open the Shaper module, then in the menu bar click on "File" > "Load Script" and select the .py file.

For STL files I used the default relative deflection of 0.0001.

Name	Thumbnail	Files	Comments
cuboid_screw_thread		.hdf .py .step .brep .stl	Introduced in 1 and mentioned in appendices of 2. Labeling-based approaches 32 will collapse the two parts of the slope, constrained to the same top and bottom planes.
cuboid_torus_with_step		.hdf .py .step .brep .stl	Introduced in 1 I believe. Here too labeling-based approaches 32 will not detect any invalidity and crush the step into the z-axis plane.
in-volume_twist		.hdf .py .step .brep .stl	Introduced in 4 Labeling-based approaches 32 will not detect the twist. The slits prevent hex-mesh extraction algorithms from un-twisting the through-hole and pushing all distorsion towards the left and right faces.
in-volume_knot		.hdf .py .step .brep .stl	Similar to the previous model, but the through-hole is twisting around itself.
pipe_helix		.hdf .py .step .brep .stl
pipe_helix_7		.hdf .py .step .brep .stl

Note

To generate a mesh, you can use the SMESH module of SALOME, which bundles open-source (NETGEN, GMSH) and commercial (3D Precise Mesh) meshing tools.

Thanks to François Protais for the ideas and to Christophe Bourcier for the help.

License

CC BY-NC 4.0

How to give attribution:

"Nightmare of polycubes" by Sébastien Mestrallet and Christophe Bourcier, licensed under CC BY-NC 4.0

Footnotes

1. Dmitry Sokolov, Nicolas Ray, "Fixing normal constraints for generation of polycubes", research report, LORIA, 2015, HAL ↩ ↩²

2. Corentin Dumery, François Protais, Sébastien Mestrallet, Christophe Bourcier, Franck Ledoux, "Evocube: a Genetic Labeling Framework for Polycube-Maps", Computer Graphics Forum, 2022, DOI, HAL, project page ↩ ↩² ↩³ ↩⁴

3. Marco Livesu, Nicholas Vining, Alla Sheffer, James Gregson, Riccardo Scateni, "PolyCut: Monotone Graph-Cuts for PolyCube Base-Complex Construction", Transactions on Graphics (Proc. SIGGRAPH ASIA 2013), 2013, DOI, project page ↩ ↩² ↩³

4. Sébastien Mestrallet, François Protais, Christophe Bourcier, Franck Ledoux, "Limits and prospects of polycube labelings", SIAM International Meshing Roundtable Workshop, March 2023, HAL ↩