Placing GameObjects next to each other

Hi, I want to place a GameObject next to another one but the position should depent if the hit.point is more to left, right, top or buttom. I came up with this

public static Vector3 relativDiagonalPosition(Vector3 hit,Transform obj){
float x = 0f;
float z = 0f;
if(hit.x < obj.position.x){
x = 1f;
} else {
x = -1f;
}

if(hit.z < obj.position.z){
z = 1f;
} else {
z=-1f;
}

return new Vector3(x,0f,z);
}​

But this does not respect the angle of the GameObject. I think I read of a method to transform a vector relativ to another vector but i can't remember which and does not find it without a propper keyword ...
By the way how do I post code correct?