control displacement direction

[gabeshaughnessy]

it'd be nice to be able to control the direction in the displacement effect, to set it to vertical or horizontal flow, and then to set left or right flow.
essentially when you held the brush tip in one location, the ink would flow away from the brush in the selected direction. when you moved the brush tip, it would still move in that direction, augmented by the movement of the brush tip.
Right now it seems like the direction of displacement is controlled by the movement of the brush and if you hold the brush still it seems to default to a horizontal flow.

[theantisphere]

good point.