RPG Design Patterns

In gauge diagrams, nodes (circles) represent gauges. A filled circle indicates that big gauge values benefit the character more than small ones. An empty circle indicates that small gauge values benefit the character more than big ones. Some gauge values are conflicted. They neither benefit nor punish a character as their values change. Or, rather, they do both simultaneously (see the Conflicted Gauge design pattern). Such gauges should be diagramed with a filled dot within an empty circle.

Characteristics that are not gauges, such as classes, gifts, and flaws, can also be diagramed. These are represented as diamonds. Gifts are represented as filled diamonds while flaws are represented as empty diamonds. A characteristic that can be considered both a gift and a flaw is represented by a filled diamond surrounded by an empty diamond.

At times, it is convenient to diagram a collection of gauges as a single node. This is done when the gauges of interest are treated uniformly in the game design. A set of gauges is diagramed as a circle containing dots or diamonds.

It is also sometimes useful to be able to diagram and reference an individual gauge that also happens to belong to a set of gauges. In such cases, both the gauge and the set are diagramed and the mathematical symbol ∋ (is an element of) is inserted between them.

Arrows represent relationships between gauges.

This diagram illustrates a relationship between two gauges. The solid line on the arrow indicates that the relationship is a direct relationship. That is, the targeted gauge value rises if the originating gauge value rises and/or the targeted gauge value decreases if the originating gauge value decreases.

A dashed arrow indicates an inverse relationship. That is, the targeted value decreases as the originating value increases and/or the targeted value increases as the originating value decreases.

Some relationships both increase and decrease the targeted gauge. Other relationships can only increase the targeted gauge value or decrease it, but not both. The ambiguity of precisely how a relationship affects the target is resolved by placing adornments on the relationship. Small triangles are placed on the relationships to clarify the relationship’s nature as shown in the following diagram:

The triangles are placed on the lines so that you can read the diagrams easily. Just remember these simple rules:

1. If the base (big end) of a triangle points toward the target, the relationship may increase the target.
2. If the tip (little end) of a triangle points toward the target, the relationship may decrease the target.

So, as you travel along the arrow from the origin to the target, if the triangle widens, it may increase the target. If it grows narrower, it may decrease the target. If no adornments appear on the relationship, then the relationship is assumed to do both.

A resource relationship is a good example of a relationship that requires an additional indicator. A resource is a gauge whose value can be “spent” in order to affect another gauge value. For example, a character may have a resource called “Skill Points” that his player may spend to raise the character’s rank in the skill of “Swimming.” This relationship might be diagramed as shown here. The relationship is an inverse relationship because Skill Points can be spent down to raise the character’s Swimming rank. But, if the character later gains more Skill Points, his Swimming rank is not going to lower as a consequence. So, the triangle adornment on the arrow indicates that the relationship can increase the Swimming rank, but cannot decrease it.

When a relationship points directly to a set, it does not affect the values of the elements in the set. Rather, the relationship illustrates that it affects the number of elements in the set. Such a relationship could be used to indicate that a resource could be spent to “buy” more skills or gifts.

When one gauge does affect the values of the gauges in a set of gauges rather than the number of elements in the set, the “element of” icon shows that a gauge is affected by a relationship and that it is also contained within a set. In the example diagram, if the upper gauge represented a character’s “Level” and the set represented a character’s Skills, the diagram would be saying that the Level gauge tends to generally increase the Skill ranks as its own value increases. It does not mean that the Level gauge necessarily increases all of the referenced Skill gauges or that it increases them equally, only that it tends to increase some of them.

Occasionally, a gauge does not affect another gauge directly, but rather affects the minimum or maximum value that the other gauge may take. In such cases, the arrow representing the relationship does not point to the gauge itself. Instead, it points to a single or double line placed next to the targeted gauge. A double line segment represents a gauge maximum. A single short line segment illustrates a gauge minimum.

Die rolls are a very common gauge used in role-playing games. The diagrams do not use a simple dot or circle to represent a roll of dice (although we could, since a die roll is merely another kind of gauge). Note that the icon is that of a six-sided die, but it can represent the roll of any kind and number of dice. The icon represents a random number generation while abstracting away the details of exactly how that number is produced.

Sometimes, games use cards to generate random values. In such cases, a card representing the Ace of Spades is used instead of a die icon or simple dot. Again, this is purely for aesthetic reasons to increase the diagram’s readability. It does not imply that a standard card deck is used, only that a card is drawn from some deck. In fact, role-playing games that use cards often have their own custom decks.

Subjective gauges, or gauges whose values are particularly fuzzy, are represented using a cloud.

Table lookups are also represented using a special icon. Table lookups always have one or more gauges providing input and they have an effect on one or more gauges.

Contests pitting two forces against one another are represented as a pair of triangles joined at one tip. Contests always have two input nodes and affect one or more gauges as output. Often times, the output is a gauge that answers a question, such as whether a character succeeds in some action. At other times, a contest generates a degree of success.

If you want to distinguish the winning side from the losing side of a contest for some reason, fill in the winning side of the contest icon.

Sometimes, a game system chooses one option from a list, such as when determining which player has the right (or responsibility) to take his turn. Somehow, the system selects one player as the next in line. The icon representing this kind of contest takes the form of a circle containing an offset triangle. This represents a kind of “dial” that turns from player to player as their turns come up.

Finally, sometimes we need to diagram actual blocks of text within the rules. These are represented as simple boxes enclosing the text. Quite often, one text block refers to another text block. When such references need emphasis, an arrow is drawn between the boxes to show the reference. In such cases, the diagram customarily contains a description of the relationship.

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