Tertiary Motion, Vector Consistency and Game Controls

In this article I discuss the problem of vector consistency during tertiary motion in video games and point at possible solutions to overcome this problem.


The Problem of Vector Consistency During Gameplay

One of the important problems that is caused by tertiary motion during gameplay is that of vector inconsistency. As the camera quickly switches from one position to another, a move which is often referred to as jogging, it is possible that the player loses the feeling of control and has difficulties in maintaining directional continuity. Since immersion requires the illusion of agency, and agency is based on a feeling of control over actions, the resulting disorientation will pull the player out of the depths of her experience. One reason for tertiary motion being so distracting is that it happens often based on a decision of the game AI, and not the character. It is normal that any player would perceive this as an interference to gameplay and a loss over agency. This problematic situation requires tertiary motion to be build very carefully into gameplay. Vector Consistency is one of the concepts that can help us in this regard.

Indeed, one of the things that the camera use in games obeys to, seems to be vector consistency.In many games the camera is locked onto the player character (based on certain parametres like distance, angle etc, which do not change during gameplay). Vector consistency is maintained during the whole process, even if we have very lively secondary motion (like in FPS or TPS games where the player constantly moves around in a 3D World).


How do Video Game Ensure Vector Consistency?

Vector consistency is maintained in a few simple ways:

1) Either the camera frame is identified with our gaze (which makes it a subjective camera), or;

2) the camera follows the player’s avatar in a pre-set way, visually assisting the player in maintaining the feel of agency.

In both cases, the camera motion is glued to the player or his representation, rarely ever leaving this locked position. Despite all the action, there is no visual jumping that confuses the player. This is quite different from what happens in film, and it is a difference that game writers need to notice. In film you rarely see scenes with cameras locked onto the subject for a long time, and if, then these scenes often aim for the creation of a specific meaning.


Vector Consistency during Tertiary Motion

However, despite the cam-lock in games, slight cam-moves are used frequently. Usually their aim is to add depth to gameplay or give comfort to the player by providing cam adjustment to the conditions. For example the cam drags behind for a few seconds when you accelerate your car in NFS, which help you to feel the energy under the hub. In some shooters on the other hand (for example Full Spectrum Warrior) the camera strafes to the right or to the left to gain more field-of-vision for the player when he rests close to a wall corner that hinders sight. However these are secondary motions in accordance with the active vector, and often contribute to the experience, rather than taking away from it. The question is how tertiary motions like cuts should be built into gameplay without making the feel of control suffer.


The 30 Degrees Rule: A solution for video games?

It has been said that a cut that changes the camera-angle less than 30 degrees confuses the film spectator, because the change in the angle usually feels too insignificant as to cause a difference in the situation it narrates. Therefore the spectator doesn’t get what reaction is expected from him and wonders why the cut actually happened. On the other hand, in games, the player gets confused when during ongoing motion in gameplay the angle changes too drastically, because the player loses connection to the motion vector he believes to “ride” on in that very moment. Maybe the 30 degree rule can be applied in a reversed way to games, meaning any cut during gameplay or player motion should not exceed 30 degrees, because as long as the cut remains in that range, the player can maintain his connection to the motion vector he feels to be riding on. If over 30 degrees, then the shift feels too big as to maintain vector continuity and the player feels like losing control over his direction. On the other hand, we also need to ask: If a angle-change less than 30 degrees feels meaningless in film, does it feel meaningless in games too?


Cutting along the Z-Axis

Probably the best way to avoid confusion during cuts is to select a frame that is located onto the direction of the motion vector that the player holds. If this is primarily the z-axis, then our cut should jump anywhere along the z-axis, preserving the initial angle. Cuts should remain in a spectrum that ranges from Long-shot to close-up's, not playing with the angle at all.


Moving the Camera when the Player stands still

Also, it could be claimed that the player will tolerate more tertiary motion if she doesn’t move at the moment of the switch, because there is a stable frame of reference that puts the camera motion in context, without causing confusion.


AI That Serves the Intention of the Player is Key

The problem of visual and vectoral continuity is less a problem when the player herself decides to change the angle and moves the camera deliberately, because then the player is fully aware of the intention behind the camera move (which simply is her own intention). It becomes rather problematic when the design of the cam algorithm is not really able to follow the basic player intentions that emerge during gameplay. The player continually will experience a lack of correspondence and feel that the game is difficult to control. Even if the cam design is ok, a player atill can mess up things and lose sight (or orientation), so some games provide this cool button that resets your view to the “standart” camera position of the game. This means you can re-build your feeling of continuity, and that is the reasons why it feels so much home, so much safe to be able to do this.


Was this article useful? Can you imagine better ways to maintain visual diversity during gameplay without endangering vector consistency and the player's feel of control? Leave a comment and share with us.
_____