I've got an animatic from a client of a segmented pie-stlye circle that 'fills in' the missing pieces. Obviously I can do this by hand, but is there a more efficient way of doing this? I can provide more information if needed - cunning plans encouraged!
i would animate the initial 'shrinking' pie shapes by hand, probably with a simple circle or the circle effect and a layer mask to create the lines... then i would probably use shatter with a custom shatter map that would be the pieces that need to explode outward.
that map would just be a still frame from the shrinking pie pieces at the point where the explosion needed to happen.
you should be able to find several tutorials on using shatter with custom shatter maps, there was a somewhat recent one that goes into quite a bit of detail (probably more detail than you need for this) here at the cow.