Yaw

In determining difficulty when it comes to positioning, taking an account of the player's body in relation to the game screen is critical. In a previous section, I mentioned the term yaw which should be familiar to enthusiasts of aeronautics. The plane has 3 axes of rotation, the roll which is the axis of rotation used to complete a barrel roll. The tilt which is the axis of rotation to complete a loop. Finally the yaw which is merely the axis of rotation used to steer the plane left and right; the vertical axis. Our bodies use this vertical axis of rotation on a regular basis to change directions while walking. When speaking of yaw, we simply mean the turn of the player's body.

To measure the yaw we use degrees as this is a rotation quantity and compare the approximate angle of the player's hips in relation to the game screen. When the player is facing the game screen at the start of play, this orientation allows for the most efficient method for reading the patterns on the game screen. Essentially, the player now has the best field-of-view to read patterns; the maximal viewfield. In this position the yaw rotation is 0 (degrees), the player's feet match with the arrows; left foot on left arrow and right foot on right arrow. As the player steps on different arrows, the rotation of the player's hips will change. As they face more left, the yaw becomes a negative number, while facing right the yaw becomes positive. Now take the following two-step pattern:

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Depending on the arrows preceding this pattern the player's feet could be on either of the arrows. Though as an aside, the foot that hits the down of any pattern determines which direction the player is facing, the opposite is true for the foot used on the up arrow. In both possible examples, the player's yaw is rotated 90 degrees from the maximal viewfield (either negative or positive, depending on which foot is where). For the sake of description rather than referring to the rotational degrees, we can define these positions as the moderate viewfields, either with a full left orientation and full right orientation. Now take a look at the next pattern.

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In this example, the arrows that would precede this pattern are crucial to determining the viewfield. If this pattern begins using the left foot hitting the left arrow, then it would describe an orientation with a maximal viewfield to the game screen. However, if our study was not concerned about our player reading arrows from the game screen but still relied on recording if they were able to do so, this pattern could begin using the left foot hitting the right arrow and the right foot hitting the left arrow. In this unnatural scenario, we can define this orientation with a minimal viewfield; the opposite of maximal. In other words, it is at this point that it is the hardest for the player to read the game screen.

Between maximal and moderate are the standard range viewfields. This area which essentially lives between the full left orientation and full right orientation (ie.: between -90 degrees and 90 degrees of yaw rotation) passing through the orientation with maximal viewfield is where most players traditionally spend their time while playing a chart. The opposite of this area, the orientations between minimal and moderate are limited range viewfields. The patterns that intend for a player to rotate into this range, which passes through the minimal viewfield, are considerably more difficult to perform than the maximal counterparts. Moving forward, we can quantify the number of times it is intended for a player to be orientated within the standard and limited viewfield ranges and hypothesize that the more intended time spent with a limited viewfield, the harder the chart should be considered. We can also quantify the number of times a player is intended to be in a left orientation versus a right orientation. As I plan to explain later, ETS syndrome will suggest that a balanced orientation is more difficult than a disproportioned one.

Double-Stepping

Not all patterns are built to allow a player to easily execute them by alternating feet. Sometimes, a pattern will suggest that the player should turn completely away from the screen. While some step-artists create this intent to quickly turn the player back toward the game screen soon after execution, other design intents will simply like to break the player's foot alternation for the sake of difficulty (or some other artistic factor). Generally speaking, this will require a double-step. Take a look at the following sequence:

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In this pattern as the player alternates their feet between the left and right, it begins fairly straight-forward. Soon, the right foot goes to hit the down arrow. If the player continues to alternate feet here, then the left foot would crossover with a lateral-transfer to the right arrow; a fairly common pattern. However, the next arrow would require the player to turn completely away from the game screen and essentially switch arrows and feet; making the right foot hit the left arrow and later the left foot hitting the right arrow. This is not an optimal body position for the player in order to continue reading the screen. It would seem that the intent of the step-artist is for the player to double-step.

When does the player double-step?

When it comes to double-stepping, the general execution occurs between the arrows where the body's yaw would turn past 90 degrees in either direction; entering a limited viewfield range. In other words, while the player is reading the down arrow from the game screen and hitting it with the right foot, the player is calculating that the next right arrow will place them in a state that makes them rotate very far away from the game screen, essentially rotating the yaw farther than 90 degrees. It is at this point in which the player makes the decision that it would be easier to read the game screen by keeping the body rotation between these two orientation extremes and inside the standard viewfield range. To do this, the player will break an alternating foot execution and move the right foot from the down arrow to the right arrow. In terms of designing, this should be the method a step-artist imagines how and when a player will execute a double-step.

The difficulty in double-stepping

In terms of difficulty, let's compare the two decisions. Certainly, without accounting for the arrows after the down arrow, a lateral transfer would be the least physically demanding option since we are continuing to alternate feet. The distance the left foot moves from the left arrow to the right arrow is roughly two panelLengths, while the right foot awaits the next move. However, when we include the next set of arrows, the body's yaw places the player into a position where it's uncomfortable to read the game screen and therefore raises the difficulty significantly.

In the double-step scenario, the left foot does not move and the right foot moves from the right arrow, to the down arrow and then immediately to the right arrow again. The distance that the right foot travels back and forth in motion is farther than a lateral-transfer. Having two transitions increases this distance in comparison to the one lateral-transfer from before. Additionally, the player's momentum is sacrificed as the right foot was acclimated to alternating with the left foot. However, this double-step is with the purpose to allow the player to continue reading the game screen and in turn continue playing the chart. A much more important factor than simply continuing to alternating feet so to keep constant momentum and minimize traveling distance. In this example we see the hierarchy of the stage rules; that the necessity to read the game screen is considered more valuable than alternating feet. We also see how the body's yaw plays as an important factor in determining how much a player is in danger of not being able to continue.