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Do you ever wish you had a magical formula that allowed you to create the next Quake or Everquest? Better yet, how about if you had a scientific formula that allowed you not only to create the next hit, but also understand, fundamentally, why it was successful? This article presents some ideas how to approach game design from a scientific tilt that will help designers to truly understand why their games work.


Currently, game design more closely resembles alchemy than chemistry. Like alchemists, game designers often use a "guess and check" approach when designing games. The designers take a "best guess" at preliminary game play, game art, and story, which are then "checked" by publishers, other designers, beta tests, and play tests. Based on feedback, the game is then tweaked until it seems "right" or time and money run out.

As in alchemy, this guess and check approach makes it difficult for the designer to nail down, at a fundamental level, what caused her game to succeed or fail. She knows what tweaks made the test audience happy, but she is left guessing as to why they worked.

The chemist, on the other hand, approaches her problem by first understanding proven principles and theories, then using these principles to achieve her goal. By using principles, the chemist knows that if her work fails she can research and understand where she violated chemical principles or find a way to modify the principles to explain her failure. Whether she succeeds or fails, she has an understanding why things turned out as they did.

For example, if an alchemist wanted to make gold out of base metals, she would try melting lead and silver together, then, if that approach seemed right, she would continue. A chemist, on the other hand, would understand that gold differs from other metals because of the differing number of protons and electrons. The chemist would then focus on trying to add extra protons and electrons into base metals. The chemist's approach is obviously favorable, as the chemist actually has some basis for her work. The alchemist is merely guessing.

So how does the designer act more like a chemist? Unfortunately, unlike chemists, designers do not have the resources to perform original research in order to discover and isolate underlying game design principles. So the designer must rely on appropriate, existing principles from other fields of study and apply them to game design. Many applicable fields of study are hundreds of years old and can offer tried and true principles to game design. By borrowing principles, game designers can build a concrete foundation of principles to work from and can allow designers to begin to create their own concrete principles specific to game design.

The Process of Liberal Borrowing

Using principles from other fields is a simple process of:

  1. Stating the goal correctly.
  2. Brainstorming fields of study that may offer insight into achieving the goal.
  3. Choosing appropriate principles from those fields.
  4. Checking principles against existing games and genres.
  5. Implementing principles in game design.

This process creates principles that are useful both in game creation and game analysis.

Example 1: Making A "Realistic" Game

For example, assume that our goal is to "create a game that displays a realistic 3D environment." To state the goal correctly, it is important to rephrase the goal so that the goal reflects the interactive nature of games; games cannot really do anything without the gamer. Thus, every goal in game design should include the word "gamer" or "player." The goal could be rephrased as "to create a game that the gamer perceives as visually realistic and three dimensional on a flat computer monitor." This goal is bulkier but more accurately states what we are trying to do; we are trying to fool a human into perceiving three dimensions.

Brainstorming yields two obvious fields of study that can help us achieve our goal. The first field is art, specifically drawing and painting. For millennia, artists have studied how to achieve 3D on a 2D canvas. The second option is to examine principles from psychology, specifically visual perception principles.

Using psychological principles to achieve our goal is the better option as psychology can be considered a "lower-level science" than art. That is, psychology can explain why many artists' principles work. Psychology often yields principles that are useful to game design, as psychology deals with the perceptions and behaviors of humans. The goal of game design is, after all, to get the player to perceive and behave within a game environment.

The next step is to choose specific principles from psychology that are applicable. We open a high school introductory psychology textbook to the chapter on visual perception. The book states that there are seven depth cues:

  1. Linear Perspective - As parallel lines recede, they appear to come together.
  2. Aerial Perspective - Objects that are farther away appear hazier because as distance increases, so does the amount of interceding dust and other particles.
  3. Texture Gradients - Objects that are farther away appear rougher and appear to have more detailed textures.
  4. Interposition - Objects that obscure other objects appear closer.
  5. Relative Size - Objects that are farther away look smaller.
  6. Light and Shadow - Bright objects appear closer than dark objects. Light and from irregular surfaces also give depth cues.
  7. Stereoscopic Vision - Human's left and right eyes receive slightly different images that allow the brain to perceive depth.

Ok, so our 3D game should attempt to have all or some of these features.

The last step is to check these principles against existing games. As it turns out, all of these principles have been used in 3D games at some time or another. In game design these principles have been implemented by use of viewing frustrum, fog, textures, z-buffer, viewing frustrum, Gouraud shading, and stereoscopic glasses respectively. While we have not discovered any "new" principles in 3D graphics, the power of this technique is two-fold: First, we know this list is "correct" as it has been "proven" by psychologists. Second, we really did not have to work hard at all - we just looked in a high school textbook, and voila, we had a features list to achieve our goal!

Actually implementing these features from scratch would require a lot of math, creativity, and coding. However, in implementing these features we can rest assured that we are not wasting our time - we are working with "proven" 3D depth cues.

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