i tried to add parallel diagonal lines. but it diagonalized only every second row, and i think that was the problem why hexagons were not possible to make.
i didn't notice that at first glance. so i diagonalized every second row by hand - whats a bit time consuming
is that workflow recommended for hexagons: dubdiv catmullclark > subdiv diagonalize > add parallel diagonal lines and ballpacking > and then dual with boundary?