We've described how the memory is updated for changes to the state caused by the client itself. There are also changes to the state caused by other players and momentum, which only affect the position of mobile objects
As mentioned above, the client can never be sure what a mobile object is doing when it is out of view. But in reality, when something moves out of our field of vision we can, for a period of time, be confident that the object is in the direction that it left our view. This is the kind of behavior that the memory model should have. In order to implement this, an estimation of the velocity of mobile objects needs to be stored. This is simply done by storing the difference in position between the current and previous time step. We factor out the change in relative position caused by the motion of the client itself using the calculation from the previous section. With an estimation of velocity for each object, we just assume that objects that aren't visible maintain the same velocity and update their position to account for it.