IPOsnap for R14 -
Interior Point osnap allows the specification of a point as a function of the distance/direction between two selected points (p0 and p1). The new point may be a specified distance (positive or negative) in the direction from p0 to p1. Or a percentage/fraction (positive or negative) of the distance from p0 to p1. Note that if one or more specified points are 3D then the point returned will be 3D.