Determining the UI strategy

For quite some time, we've struggled to find a model that we can use to separate different FPS games from each other and see what game characteristics that affects the UI strategy suitable for the game - a ground for UI design guidelines. In this post, I will describe one approach to this.

There are at least five factors that in some way have a direct impact on the UI of a FPS; Level of Competition, Fiction Persuasiveness, Spatial Interaction, Rules Transparency, and Level of Vertigo.


The level of competition of the game determines whether an overlay 2D HUD might be a reasonable strategy or not. In games based heavily on narrative (level 1), designers might wanna go for an approach that pursues something that draws close to the notion of immersion, by working with diegesis and avoiding a traditional HUD breaking the illusion. However, the more competitive elements the game experience builds on, the importance of being able to make strategic gameplay decisions grows for the players; in pure multiplayer games (level 3), it is also important do make these decisions fast. Hence, ambiguous information should be avoided in these situations, which is most easily achieved with an overlay HUD.


The fictional persuasiveness of the game determines how important the notion of diegesis is to the game UI. In games with fiction that attempts to deliver a game world nearly identical to the real world during some time in history (level 3), slightest non-diegetic element might break player immersion. In games that delivers plausible worlds that are quite different from our own (level 2), diegesis might be just as important, but can be allowed by using artifacts and entities that builds on the game fiction (sci-fi, post-apocalyptic, etc). If a game does not try to hide the fact that it is an artifical world (level 1), the level of diegesis might not be an issue at all.


We think that when the 3D geometry affects gameplay, it also affects the UI regarding interface elements with spatial qualities. If the geometrical aspect of level design has no direct impact on gameplay (level 1), there is no or little need for UI elements presented spatially in the 3D space. However, as the importance of the geometry grows for the player (level 2, 3), the UI should support this by providing short-term navigational guidance and strengthening environmental affordances. If full diegesis is not a design goal, UI designers can work with spatial information such as the runner vision or checkpoint beacons in Mirror's Edge - if diegesis is important, signifiers might be a better tool.


The rules transparency of the game impact on how affordances is conveyed to the player, and the diegesis of the learning/tutorial approach of the game. If the game does not make the slightest attempt to hide the fact that it is governed by a rule framework (level 1), affordances can be conveyed by fairly straight-forward approaches such as pure textual feedback ("Press x to pick up weapon.") throughout the whole game. If this strategy is not desirable (level 2), designers should make an effort to restrict non-diegetic affordance references to a tutorial part of the game, and convey the rules in a somewhat more diegetic way ("You must find the fire escape ladder to gain access to the building" instead of "Find the exit to proceed to next level").


Finally, the level of vertigo determines how the game should make up for the fact that the only links to the perception of your in-game avatar are graphics, audio and rumble. If the gameplay is sensory-poor (level 1), this link is of less importance. However, as the gameplay draws on sensory-rich elements such as height or speed (level 2), the player needs to be linked closer to his/hers game-ego. This can be achieved by exaggerating (meta-representations, according to our previous terminology) and fortifying these senses visually, sound wise, or by rumble; for example blurring the edges of the screen (used in racing games, and Mirror's Edge) to indicate speed, or exaggerating traffic noises when jumping between rooftops.

The design space revisited, once again

Inspired partly by the work of Jesper Juul mentioned in the previous post, we have once again taken a look on how the design space can be modified even further. In the last proposal, we laid forth a UI design space with two dimensions; the spatiality in relation to the 3D game space, and the existential qualities within the fictional game world. Jesper Juul speaks of the game space as a meeting between fiction and rules. As mentioned before, there are cases (from an UI point of view) when fiction and rules do not overlap but are still in the game space, resulting in information outside the fiction part of the UI but within the rule space; for example runner vision in ME. In a similar way, there are cases when fictional and rule-based entities is presented outside the (3D) game space, such as overlay GPS systems or the GTA4 cell phone.

An alternative take on the UI design space would be to describe it as the collision of the 3D game space, the fictional space, and the rule space. The old design space expanded with a rule dimension, sort of.


What's good about this? Traditional HUD elements today resides only in the rule space, outside the 3D game space and the fiction space. To pursue an immersive/engrossing experience UI designers should focus on pushing the UI closer to the core of the design space.

Another advantage is that the model can be exploited from different directions depending on the nature of the game. A competition based experience is a lot about rules, a mimicry-heavy game experience is a lot about the fiction, and pursuing vertigo is a lot about feeling that you are one with the 3D game space, which means that depending on a games focus, the model can be exploited from different directions. For example, if a game is heavily competitive an overlay HUD might actually be preferable while signifiers might be regarded as vague information, while in a heavily mimicry based situation spatial and non-diegetic representations might break the immersive experience. Exploitation of the earlier design space differed a lot depending of the nature of the game.

This UI design space also illustrates the role of the game UI designer as we see it, being involved with both game designers (rule space), level designers (game space), and fiction/art director (fiction space).

The design space revisited

The design space we settled for about a month ago relies heavily on the notion of diegesis. One problem with the notion of diegesis is that there are some potential gray areas between what is diegetic and what is non-diegetic. Take for instance the blood stains appearing when taking damage in Killzone 2; having your face splattered with blood seems quite realistic given that half of the characters' body mass consists of blood (which is usually a convention in action games), but the visual effect would most certainly not be distinctive blood stains on your eye retinas. Or the Mirror's Edge runner vision; objects in the game world with the potential of aiding your traverse of the terrain the turns red, yet is this what Faith really sees?

This might motivate an effort to look at an alternative way of mapping out a design space in which diegesis is not a dimension itself, but rather an area within the design space.


If the spatial dimension (is the UI element presented in the game space or not?) of our design space was to be kept, and the diegetic dimension is replaced with the existential qualities of the UI element within the game world (does the representation exist in the fictional game world or not?), the design space would be represented by the model pictured above.

Information representations that is presented spatially in the game space and exist as entities in the game world, are diegetic representations. Take for instance the Doom 3 data terminals; they exist in the game world, they are also presented in the game space, and are hence very much diegetic. The same can be said for the Dead Space menus; the tech setting of the game (sci-fi) allows projecting information on virtual surfaces, hence the menus are not only a part of the game space but also of the fictional game world itself.

Representations can exist in the game world, but aren't necessarily visualized spatially for the player; these are meta representations. The Killzone 2 example above is an example of this; characters bleed when they get hurt, however the blood is visualized as stains on an overlay camera lense rather than in a realistic fashion. Other examples of meta representations would be the GTA IV cell phone (a 2D overlay representation of the character's cell phone), heart-beat audio indicating critical health level (you normally wouldn't hear your own heart beats, yet they exist and can be heard by others), ambient sounds such as thunder or breezing wind (usually just zone/area specific rather than actual spatial 3D audio sources), or the old Doom head indicating character health level and status (an overlay representation of the character's head, which is a representation of the status of the player).

Non-diegetic representations are disconnected to both the game space and the game world. This would be traditional overlay HUD elements such as health bars (there is no health bar visible for the in-game character), ammo digits representing how many bullets that are left in the clip, dynamic music, sub-titles, etc.

Finally, UI elements could be presented in the game 3D space without being an entity of the actual game world; spatial representations. Here, we find examples like the character outlines of Left 4 Dead (none of the game characters actually see the silhouettes of their teammates through walls, yet they are visible for the player), the highlighting of interactive/pickupable objects, Faith's runner vision in Mirror's Edge, Dead Space path guidance, or check point beacons in Mirror's Edge.


So what's the point of tearing down the design space just to re-assemble it in a slightly different form? Given our results and reflections so far, it seems like spatial representations and meta representations can be used to engross the player even deeper than what would be achieved with a completely diegetic UI! Spatial representations can be exploited to strengthen the player's in-game perception regarding external information - UI solutions such as runner vision in Mirror's Edge or the teammate silhouettes in Left 4 Dead makes up for the fact that players tend to loose their sense of direction when moving about in a virtual 3D space. Similarly, meta representations can be exploited to strengthen the player's perception regarding internal information; blood stains and heart beats, or even the old Doom head, helps players make up for the fact that the physical game interface (TV, speakers, controller) does not allow players to connect with their in-game avatar using the broad set of senses that is available to us in the real world.

Charts: The Design Space and How it is Exploited Today

One possible charting of the UI design space of FPS games is to divide it into three dimensions: the information channels (how is the information conveyed?), the diegesis of the information conveyed (is the information diegetic or non-diegetic?), and the spatial quality of the information carrier (does the information representation exist in the game 3D space or not?). If this division is made, a four-field chart of each main information channel (visual, audio, haptic) can be produced. By putting examples (from the objective and subjective game study) into the charts, we can see how the design space is exploited by games today.

VISUAL INFORMATION


Game developers today mainly tend to use non-spatial visual information carriers (2D overlay elements, image filtering) to convey information. Spatial representations seem to be used to a far less extent; here, few conventions exist, hence exploration might reveal quite innovative ideas on how to information can be conveyed.

AUDITORY INFORMATION


As far as game audio is concerned, diegetic information represented in a non-spatial way seem to be the most exploited area (allthough there's probably still plenty of the area left to explore) when it comes information more sophisticated than mere auditorial feedback on explosions and weapon fire. Games such as Left 4 Dead (teammate dialogue, characteristic special infected sounds) shows that a lot of potential also reside outside of this area.

HAPTIC INFORMATION

Similar to the auditorial dimension, developers today tend to exploit controller rumble mainly in a diegetic non-spatial way. In most cases vibrations seem to be exclusively used for giving feedback on being hit by enemy fire and/or when the player use firearms. Looking at examples from other game genres, it's clear that there is a lot of unexplored space when it comes to the haptic dimension of the design space.