first thing, there is no special tool to slice.
you gotta copy the brush you want to cut into pieces, then you cut off the first piece,
paste the whole brush over the already cutted piece and cut the second piece!!
afaik you cant do that, so youll have to replace the x-axis, y-axis and z-axis values and push "ctrl+m",
then a new window will appear and there youll be able to rotate the cylinder...