In both cases, we work with solely those cases where unbounded network lag can cause extremely undesirable effects, such as a frozen world. For example, navigating through a scene, while initiated by a participant, is generally not a source of unbounded network lag, as navigation is typically handled locally. Thus, we make no attempt to mitigate the effects of lag on navigation, though there is lag present and our effects could be reformulated perhaps to address that lag.
Typical actions initiated by a participant include grabbing an object and moving it through a scene.
Grabbing a shared object is a source of network-based lag, as a shared object must be controlled by a mutually exclusive lock. A user interface that does not allow the user to manipulate an object until a lock is granted could have disturbing pauses. If the pauses were long enough, they would prevent the user from feeling in control of the object. Conversely, if the UI lets the user manipulate the object before the lock is granted, the user will lose control once the system realizes that the user does not in fact have permission to modify the object. Some have suggested that social conventions can suffice in place of a lock, such as a convention that users not grab objects that others are already holding.