Returns the unit vector defining a line through p and tangent to cir. Cir must handle the Arc protocol (as by ArcMixin). OnRight? is used to determine which tangent is desired. If True, it selects the one on the right side of the line from p to the center of cir.
Syntax
pointTanArcV ( p As Point, _
cir As Part, _
onRight? As Boolean ) As Vector