The grazing point is the point of closest approach to the surface of the selected central body along a defined direction.

The grazing point is the point of closest approach to the surface of the selected central body along a defined direction. To define a grazing point, start by defining a reference point which will serve as the starting location for the line along which the grazing point will be computed. Next define a direction to be used in conjunction with the position vector from the selected central body to the reference point to define a plane in which the line will lie. The grazing point will be computed starting with the line aligned with the specified direction, then rotating the line in the plane until the point of closest approach to the central body surface occurs at the specified altitude. An altitude specification of zero indicates that the line will \"graze\" the central body.