I have a box (cuboid) lying on floor or table. So there are 6 surfaces of the box and 1 surface of the floor. If I take each pair of surface such that the surfaces are "adjacent" to each other, I get two kind of pairings:
1) two surfaces of the box: the surface normals of the surfaces diverge from each other.
2) 1 surface of the box + surface of the floor : the surface normals converge and intersect at an angle of 90 degrees. ( 8o to 100 degrees, if we want to add some tolerance).
I want to distinguish these two cases by representing through a function? What function can distinguish between these two situations?
In both cases, the the normalized dot product of the surface normals is 0, since the angle b/w them is 90 degrees. So this is not the right solution...