Now, you tell suppose I took this coordinate here, so what happen? I shifted this body from here to here, raised it and then tilted it, so I have got this much, this much that is this much is x displacement, this is x z displacement and rotation. Now, supposing I took the point here, fix point coordinate here, I can always take the coordinate here, because its fix point, then my displacement would have been this much, this would have been this much and rotation may have been something else also, depends on which point I take