The position and orientation of an object in real life can be described with direction and magnitude, e.g., the TV is 3 meters in front of me. While that description is good for me, it might be that for someone else in a room, the TV is 5 meters to the right of that person. Information about objects is given in the context of a reference frame. Usually, in Computer Graphics, objects need to be expressed with respect to the camera frame. This article covers why we need to have multiple reference frames and the math needed to express objects in a different reference frame.