main/src/georegression/metric/ClosestPoint3D_F64.java
public static Point3D_F64 closestPoint( PlaneNormal3D_F64 plane , Point3D_F64 point , Point3D_F64 found ) {
		if( found == null )
			found = new Point3D_F64();

		double A = plane.n.x;
		double B = plane.n.y;
		double C = plane.n.z;
		double D = plane.n.x*plane.p.x + plane.n.y*plane.p.y + plane.n.z*plane.p.z;

		double top = A*point.x + B*point.y + C*point.z - D;

		double n2 = A*A + B*B + C*C;

		found.x = point.x - A*top/n2;
		found.y = point.y - B*top/n2;
		found.z = point.z - C*top/n2;

		return found;
	}
public static Point3D_F64 closestPoint( PlaneNormal3D_F64 plane , Point3D_F64 point , Point3D_F64 found ) {
		if( found == null )
			found = new Point3D_F64();

		double A = plane.n.x;
		double B = plane.n.y;
		double C = plane.n.z;
		double D = plane.n.x*plane.p.x + plane.n.y*plane.p.y + plane.n.z*plane.p.z;

		double top = A*point.x + B*point.y + C*point.z - D;

		double n2 = A*A + B*B + C*C;

		found.x = point.x - A*top/n2;
		found.y = point.y - B*top/n2;
		found.z = point.z - C*top/n2;

		return found;
	}
Finds the closest point on the plane to the specified point.

@param plane The plane
@param point The point
@param found (Optional) Storage for the closest point.  If null a new point is declared internally.
@return The closest point