When in Edit Mode, I find sometimes I want to move an edge, or at least two vertices, in a direction that would be perpendicular to their orientation along their existing edge.
At that moment, the Transformation Orientation selections (Normal, Local, Global, et al) have no vectors pointing in that direction.
How might I, or is it possible to, change the "polarity" of those manipulator vectors (independent of the given selections: Global, Local, Normal, Gimble, View) so that one of them is pointing in the perpendicular direction to the line/edge between the vertices?
