@Charles_Gueunet Yes it was a typo.
PolyhedronOffsets is an array that provide the position of a polyhedron start in the PolyhedronToFaces array as well as the number of face of a polyhedron.
It is sized following the number of unstructured cells meaning it stores useless information about non polyhedral cells (They have a zero size). Maybe it could be sized along a NumberOfPolyhedronCells to keep only relevant data and minimize disk space but then it will need a bit of computation on CPU side during write and load to build a mapping.
The behavor mimics the Connectivity + Offsets.
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