specifies the direction vertices are moved when affected by a
brush.
Center Normal moves vertices
in the direction of the normal of the face directly under the
center of the brush.
Averaged Normal moves vertices
in the direction of the average of the normals of all affected
faces.
Vertex Normal moves each
vertex in the direction of its own normal.
Forward moves vertices in the
direction of the stroke.
Right moves vertices
perpendicular to the direction of the stroke.
X moves vertices along the X
world space axis.
Y moves vertices along the Y
world space axis.
Z moves vertices along the Z
world space axis.
Camera moves vertices toward
the camera.