[Paraview-developers] How to construct hexahedra from vertices and edge connectivity

[Deij-van Rijswijk, Menno]

Hello,

I have the following challenge at the moment: I’m reconstructing an unstructured grid that consists only of hexahedra, given only the vertex and edge connectivity information.
So far, by enumerating all 4-cycles emanating from each vertex, I have successfully identified all quad faces. But I’m struggling a bit with the next step: given all the faces (and their edges), how to quickly identify all hexahedral cells? Currently I have implemented the following brute-force approach:


1.       For each face F, find all faces that share one edge with the face (typically ~12 adjacent faces are found)

2.       Enumerate all combinations of four faces in this list of adjacent faces ( 12-take-4, about 500 combinations)

3.       Select the 4-tuples of faces that have exactly 12 unique edges (typically ~8 combinations left)

4.       From these ~8, select the ones that can be capped by the original face (F) (this is given by the step 1) and an existing other face.

Like I said this is brute-force approach (that does work). Are there smarter ways to accomplish the given challenge?

Thanks and best wishes,


Menno Deij – van Rijswijk


dr. ir. Menno A. Deij-van Rijswijk | Researcher / Software Engineer | MARIN Software Group
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