In a recent japanese videogame tech magazine, (why don’t we have these?), Namco discusses the optimisation of Soul Calibur’s female skeletons from the PS3 to the PSP:
In both Soul Calibur IV and Soul Calibur Broken Destiny, everything, including fabrics, is animated by “bones”.
On the PS3, there are two separate bones in each breast, giving a total of four, and it is these which give rise to breast motion, whereas on the PSP for the sake of load reduction things had to be simplified. We managed to obtain satisfactory results with only one “bone” across both breasts.
Swaying breasts may be most enjoyable, but from time to time we are warned that they move a little too much.