3. Tuning - extensive, minute adjustments of the specific parameters governing the movement of the player-controlled avatar.

Once our system is designed and our motions mapped, we are left with a set of parameters. Ideally, these parameters can be viewed simultaneously, because what is important is to view them as a cohesive whole, to understand the relationships between them. Balancing them against one another – making small alterations, testing the results - is the primary way to arrive at a certain feel.

At this point, is useful intellectually to delineate between local and global parameters. Local parameters apply only to the specific avatar object which is being controlled. Mario’s jump, for example, is a local parameter, as is the speed of his left and right movement (which will be tuned as one parameter as it should always be the same left as right.) Generally speaking, any motion that is directly triggered by the player is a local parameter. It is in these parameters primarily we can address player feedback about feel.

A global parameter is one that affects all objects equally, such as gravity. Oftentimes, pairs of parameters work as foils to one another and must be balanced in pairs. Gravity versus jump power, for example. Less gravity means greater jump height and vice versa. Remember, though, that gravity is a constant that every object in the game uses and therefore changing it has significant ramifications for the interaction of all game objects. To return to the system design for our Asteroids example, do we want all objects in our world to be dampened? For this game, probably not. We want the asteroids to float around as if in space, and the ship to continue forwards endlessly, frictionless, until the player fires the thruster while facing the opposite direction to slow down or change course. So, all we really want is rotational dampening on the ship, a local parameter. We alter our system to accommodate this, and re-tune all our parameters to achieve a more responsive feel.

One final consideration for tuning is level design. The spatial context in which the movement of the avatar occurs is of paramount importance. Much as the sensation of speed in an airplane at 10,000 feet is less than a car on the freeway, the feel of a mechanic needs context to have meaning. The plane is moving much more quickly than the car, obviously, but there is no impression of speed because there’s nothing flying by the window to use as visual reference. Virtual sensation is entirely comprised of these kinds of impressions, so the design of the level, the layout of objects around the avatar, their size and so on, is the framework for processing the feel of a game. A driving mechanic may feel clunky and unresponsive if obstacles are spaced too closely relative to forward speed and turning (causing constant collisions.) If the obstacles are spaced further apart or the forward acceleration and steering parameters are adjusted, the feel becomes smooth. In this way, level design is simply another parameter to balance local and global values against.

Player classifications of feel and their meaning:
Below, I have classified the common player descriptions of feel mentioned earlier by attempting to correlate them to the parameters, global and local, which give rise to and affect them. There seem to be some redundancies and overlap, such as between “twitchy” and “touchy”, and in many cases the descriptors seem to pair off as opposite extremes (tight versus loose, stiff versus smooth and so on.) A possible next step in formalizing these descriptions of feel in game could be survey and interview-based study looking for more native categorizations and attempting to further correlate them to parameter relationships and known behavioral phenomenon.

Floaty
“…the action in the game just feels too floaty overall. There’s very little sense of speed or acceleration, either while on the powder or in the air.” (Amped 2)

When a player says a mechanic feels too floaty, they are often referring to the relationship between forward movement and rotation. Specifically, how quickly a player’s turning input causes a change in direction. If the avatar object can pivot a great deal before a change in heading occurs, as though it is sliding across ice, it will feel floaty. If instead it “carves”, seeming to grip the terrain, dig in, and cause a quick, arcing direction change, it will be perceived as being tighter-feeling. If the object being controlled is in contact with the ground, we can emulate the natural phenomenon that causes cars and other vehicles to make sharp, arcing turns, friction. It is also possible to add a dampening force proportional to the amount and/or duration of turning. For example, if a turning force is applied while a car avatar is moving forwards at 10 units per second, an arbitrary force could be applied in a direction opposite to the car’s forward movement depending on the sharpness of the turn, assuming that the input device being used has enough sensitivity to accommodate a nice range of turning. This will cause the car to appear to carve as if on dry asphalt rather than sliding sideways, as if on ice.

Twitchy or Touchy
“Unfortunately, these games are also the most unevenly re-created, with spotty and unfaithful sounds and–worst of all–twitchy controls, regardless of what input method you select…as previously mentioned, the controls for all of these games are very twitchy and overly sensitive.” (Atari: 80 Classic Games in One)

Twitchy seems to be the opposite of floaty, when the controls are too responsive and the player feels as though the slightest movement will send them veering off their desired course. In this case, we would seem to have too much sensitivity, or not enough range of sensitivity. Try making the range between the smallest and largest possible force applied (especially applicable to turning forces) larger, and mapping it non-linearly, such as with a Bezier curve.

For small movements of the input device, the reaction is very slight. The stronger the input (the farther a thumbstick is pulled away from its neutral position, the faster a mouse is dragged, the longer a button is held) the stronger the turning force.

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Part 3 of 3 coming on Saturday (I teach from 8am to 10pm Fridays).

- Swink