With an orbiting camera, the camera will always look toward the center of the world. Therefore, we will always use the z-axis to move to and from the object we are examining. However, with a tracking camera, since the rotation occurs at the camera location, we can end up looking to any position in the world (which is ideal if you want to move around and explore it). Thus, we need to know the direction in which the camera is pointing in world coordinates (camera axis). We will see how to obtain this next.