Let's have P^3 with some transformation M that is 4x4 matrix, builded from four basis column vectors (V1, V2, V3, V4) (x,y,z,w). then vector perpendicular to infinity plane (W = 0) is (V1w, V2w, V3w, V4w). what i need some convinient, standart name for this "vector perpeducular to infinity plane"... may be something like "projection vector", "infinity plane vector"?

PS: thanks for help, and sorry for bad english