“…Both tissue compressibility and facial pose variation can be circumvented by performing measurements on a mannequin head 8,11,12,15,17,18,20,23,24 , or plaster casts 13,25 . Other studies replace direct anthropometric measurements with (repeated) digital ones 18,[21][22][23]29 , use electromagnetic digitizers, coordinate measuring machines 13,15,30 , or other stereophotogrammetry devices 10,11,15,17,24,25,27,33 as the gold standard for comparison.…”