This paper analyzes the design space for crafting systems within games. A crafting system is the collection of game mechanics which enable a player to create virtual objects within a game, with examples ranging from making a pickaxe or placing blocks in Minecraft , to combining ingredients to create items in World of Warcraft , or designing a city in SimCity . Within both game design and game journalism there is no systematic understanding of what crafting means in games — rather, the term is used in an informal “I’ll know it when I see it” way, with different ideas of what constitutes “crafting” becoming conventional for different game genres. We aim to create a more systematic analysis and language for virtual crafting, using a design space approach where we identify seven features of crafting systems; any given crafting system is understood in terms of the degree and manner in which it exemplifies these features. The features we identify are: recipe definition (how well-defined are the player steps for creating a virtual object), fidelity of action (how detailed is the player-performed enactment of crafting), completion constraints (how is creation constrained by virtual “resources”), variable outcome (how much can the result vary when the player performs the same crafting actions), system recognition of outcome (to what degree do other game systems “understand” and take account of what a player has made), player expressiveness (how big is the creative space provided to the player), and progression (how do the possibilities of crafting change over time). We apply these dimensions to the analysis of 64 crafting systems across 47 example games. This more systematic analysis of the crafting system design space provides a deeper understanding of how games function as a creative and artistic medium for players, and provides a language and framework enabling scholars, critics and developers to more deeply understand existing crafting systems as well as unexplored opportunities for future crafting systems.

This paper examines the role of crafting systems in games and analyzes seven design dimensions of crafting mechanics. First, we’ll examine some related work to give a perspective on various frameworks in use in game studies, and then take a brief historical tour of real-life crafting and design literature. Then we’ll break down each crafting dimension in detail, going over what the dimension scores represent and giving some illustrative example games at different positions along the dimension. Next, we will mention important external forces involved with a crafting system, such as social play and player communities, and how those forces interact with the design dimensions. Finally, we’ll wrap up the taxonomy and invite future discussion on the topic.

After this initial review, we struggled to relate the many and often disparate features of crafting in games. We could not find a “canonical” crafting game, nor did we find it effective to try to describe a set of categories that neatly discretizes the space into mutually-exclusive groups of games or crafting systems. We instead identified core attributes of crafting which different crafting systems had to varying degrees. The attributes were orthogonal and nonhierarchical; having one attribute didn’t require or preclude a game from having any other. Drawing inspiration from past work in game studies by Jesper Juul, we created a seven-dimensional model of crafting systems that described meaningful mechanical differences within the games [ Juul 2005 ]. This inclusive taxonomy approach, involving placing terms at an intersection of orthogonal, scalar dimensions, has proven illuminating and influential in game studies and is further discussed below. After we first drafted our dimensions, largely inspired by our survey of prototypical crafting games and literature on real-world crafting, we set about formally encoding specific games in the taxonomy one-by-one (or assigning values for them on each dimension). This process revealed some ambiguities and redundancy in the taxonomy, which we then fixed. We refined our taxonomy in this way over the course of about three months, adding to our set of sample games, discussing and plotting them on the dimensions, editing — and sometimes removing — dimensions, and repeating the plotting process over again for all games collected thus far. We stopped when we no longer needed to refine the taxonomy to adequately capture new sample games, and when our set of sample games was sufficiently large and diverse, even capturing edge-case crafting systems. A full report of every crafting system we evaluated, their rankings on each dimension, and a brief description with justifications accompanies this document as a stand-alone visualization website, which can be found here: users.soe.ucsc.edu/~agrow/craftsystems [5] . Github access to the visualization website, minus the additional gifs, can also be found here: github.com/agrow/craftsystems

To generate these dimensions, we started by carefully reviewing a selection of games that have clear instances of player creation. We looked at the games themselves, as well as secondary literature around these games. Because crafting is tied strongly to the real world, we also reviewed literature around non-virtual crafting. Our taxonomy is built from concepts that have been identified in other games studies work, as well as important concepts in the study of real-world crafting.

With these diverse examples in mind, we might roughly say that crafting in games is the thoughtful manipulation of materials by the player to create something else within the context of the game.

When a player performs actions similar to those of a real-life crafter, or goes about creating a virtual object using the mechanics, the system of those mechanics may be colloquially known as a crafting system by the game’s designers and/or players. “Crafting” is advertised as a feature of games fromto(and is even included in some of their names). However, games implement their “crafting” vastly differently; in, crafting is highly abstracted, conducted through menus, and linked into a vast player economy of items, goods and services. Crafting inis far closer to playing with LEGOs, asstructures are built by players placing virtual blocks on one another. These creations range from giant masterpieces to bare-bones boxes that let players survive the dangerous night. This type ofcrafting is quite different even from several other crafting systems withinwhere players use a dedicated set of crafting menus to instantaneously create and place objects into the player’s inventory. A third contrasting example would be, a text-only browser idle [3] , or incremental, game which includes evolving recipes [4] and large-scale automation. A quick look at these three games shows three very different forms of design and creation within game crafting systems.

To build this understanding, we construct a taxonomy of crafting in games. Taxonomies are a common tool in game studies, often used to discuss either types of players [ Bartle 1996 ] or games and simulations themselves [ Klabbers 2003 ]. We take the latter, game-centric approach. Taxonomies create a shared vocabulary around complicated concepts to allow a deeper and better-organized study of those concepts, which is the aim of this article.

Making, creating, building — the language typically used to describe these experiences — are vague descriptions for the complex fields of creativity and design. We need to build a finer critical vocabulary around these systems to more effectively discuss them. Additionally, crafting systems are often deeply integrated into other game systems and mechanics, or operations of the game: working as the production side to a rich in-game economy, or as vehicles for player or game progression. Understanding the kinds of play crafting affords the player, or where a crafting system could fit into a larger game’s context, is currently under-explored in game studies.

Crafting is a creative and pleasurable alternative gaming experience — thus often speaking to different audiences than playable media centered around combat systems or resource management. While players can be creative and express themselves through game actions that do not involve creating [ Wright et al. 2002 ], creativity that results in the existence of something new supports a creative pleasure not obtainable otherwise., and, while vastly different in subject matter (urban planning, house design and decoration, and block placement, respectively), are all underwritten by player creation in virtual worlds, and have all been highly influential, popular-culture phenomena in their times. Much of their connected successes are in the novel experiences they enable, all primarily driven by crafting. These pioneering, crafting-focused games have transformed the playable media landscape, inspiring entirely new genres of simulation and open-world, sandbox games [ Ondrejka 2004 ] [ Rose 2014 ]. A new, more diverse audience of players has also been drawn to these experiences, noteworthy in the field’s straight, white, male-dominated history and tenacious reputation [ Kafai et al. 2008 ] [ Shaw 2015 ].anddrew mainstream media headlines for their equal gender appeal [ Paulk 2006 ] [ Thompson 2003 ], andhas been deployed in diverse classrooms for experimental creation-based learning [ Smaldone et al. 2016 ].

Crafting in games affords a unique kind of interactive experience, only possible in playable media, and made increasingly rich with the complex computational modeling of videogames [1] . It enables players to create items and structures without the cost, effort, and destructive modification of raw materials in the real world. It provides spaces of playful experimentation and creative expression, wherein ordinary people can design and create whole buildings, cities, geographies, machines, rocketships, gardens, and creatures, without a difficult-to-acquire formal education, specialized knowledge, or extraordinary resources. Games provide a context of playfulness that removes the inhibiting pressure to make something perfect or to fulfill a practical purpose. Crafting in games often supports creativity as intrinsically pleasurable, rather than as a commodified, extrinsically-motivated way to accomplish tasks, much like the casual creators genre identified by Compton and Mateas [ Compton 2015 ]. It also means that people can create things that would be altogether impossible in the real world. These creations then exist in the context of a game world; what players craft in a game becomes part of the game, taking on a new life, whether becoming part of a graphically modeled, physically simulated landscape, or an item that the player-character can use, wear, trade, or consume. This is all to say that crafting in games, while sharing much in common with real-world crafting or digitally augmented crafting [2] , is also made significantly different by its context in playable systems.

We call this property “aesthetic diversity”, the quality of having many variations on a theme in a collection of crafted objects. This sort of variation is often not enacted in crafting systems, in fact, crafting systems almost always fall under the workmanship of certainty. Reasons for this are discussed in the Undefined Recipes and the Variable Outcome dimensions. Automation affordances often work against aesthetic diversity, as is discussed in Automation.

While the quality variation of the workmanship of risk may seem undesirable, Pye argues that it is desirable for producing subtle variation across created objects. Mass production (and the high degree of the workmanship of certainty required for it) “lack[s] all depth, subtlety, overtones, variegation, diversity…” [ Pye 1968 , 19].

To Pye, the quality of a craft is determined based on how closely it follows or augments a particular intended design. Regulated workmanship is when the design and final crafting result very closely match. By definition, the workmanship of certainty is regulated. The workmanship of risk is permitted to be worse than the design (thwarting it) or better (augmenting it).

According to David Pye in, workmanship can be broken into two contrasting groups, “the workmanship of risk” and “the workmanship of certainty” [ Pye 1968 ]. The workmanship of risk is workmanship where the quality of the result is at risk during the process of making — a workman can make mistakes in the act of crafting. In the workmanship of certainty, the quality of the item is predetermined at design time, usually by automation [ Pye 1968 , 20].

Related to evaluation of crafts is motivation: why do people craft, in games or otherwise? Unfortunately, to the authors’ knowledge, there is not a quality source that outlines what motivates players to craft in games. We can, however, extrapolate from the reasons why people craft in general and begin to evaluate how they may or may not apply to crafting in games. Winge and Stalp did an ethnographic study of 44 crafters, primarily subversive ones, and some of their reasonings were: for necessity (or lack thereof), to develop skills (learn), to relax, to have fun, to create a supportive space, and to develop identity [ Winge and Stalp 2013 ]. Many find it “therapeutic” to quietly reflect, or think about nothing at all, and to watch a product slowly unfold [ Winge and Stalp 2013 , 75]. To summarize, some craft to make a specific object or outcome, and others for the process of making regardless of the outcome. While the value of a specific object may be worth the cost of admission to create it, in the real world or in a game, the process is the more interesting motivation here. Through Csikszentmihalyi, we find a common thread to games and crafting: the flow state [ Csikszentmihalyi 1996 ]. While not the only feeling involved in the process of crafting, the flow state — where there is a balance of challenge and skill that consumes a person’s whole concentration — is shared with gaming in general, as well as crafting within the game, and is likely one major motivator for players to seek crafting systems in games.

What is creativity, then, as a necessary component of a creative endeavor? In general, many researchers of human and/or computer creativity agree that the “standard definition” is some combination of originality (or novelty, or innovation) and effectiveness (or appropriateness, or usefulness, or value) [ Runco and Jaeger 2012 ]. Most games do not try to operationalize or evaluate creativity and instead leave it up to player interpretation. However, some games, such as those discussed in the System Recognition dimension, attempt to procedurally evaluate, model, or simulate some qualities of entities made by the player.

The Industrial Revolution’s toll on an individual’s creative freedom was being felt widely enough to seed an international shift in values, the Arts and Crafts movement, across Europe, in other nations in the British empire, in North America, and later in Japan [ Dormer 1997 , 35–36]. This movement defined and popularized the concept of “craft” as this paper refers to it: as a creative endeavor alongside and sometimes including the fine arts [ Dormer 1997 , 38]. In the games we have analyzed, we consider everything from drawing to city-building and spell-crafting to fall under the umbrella of crafts.

Many sources, including those cited previously as well as David Gauntlett’s bookspeak to the current renaissance of craft knowledge and products spread throughout the internet [ Gauntlett 2013 ]. Popular websites such as, andencourage users to share their own patterns; and commerce websites likeorexist for users to sell their handmade goods and materials. It is not surprising, then, to see crafting systems and other creative acts being integrated into more games, leveraging art, craft, DIY, and engineering visual design or theming with or without mechanics or systemic models of crafting [6] . A game’s craft aesthetic can wrap around and re-influence real-life crafting, which has been reported by the developers of Westecott 2011 ]. Games that do make crafting playable are also often supported with a library of patterns, economies, and player strategies that mirror communities of real-life crafts (see Social Aspects below for more detail).

Craftivists, practitioners of a specific subculture of the maker movement, create crafts as a means of political self-expression, such as graffitiing with yarn, or “yarn bombing,” in the effort to reclaim cold public spaces [ Mould 2014 ]. Some games such as, a rollerblading action game about tagging graffiti and evading authorities, attempt to faithfully model transgressive behaviors. We would consider transgressive crafts within games as within the scope of this paper. The practice of taking “Grandma’s crafts” — traditionally feminine crafts, such as scrapbooking, knitting, sewing, and other textile crafts, used to convey “deceivingly harmless” messages reinforcing gender, religious, political, or familial identity or ideology — and inverting, twisting, or otherwise subverting their usual meaning is known as subversive crafting [ Winge and Stalp 2013 ]. Modding, a jargon term for modifying a game in any way outside of the scope of the gameplay, could be considered subversive or transgressive craft if the craft in question is game creation or game authoring [ Letzter 2015 ]. However, the scope of this paper is crafting systems modeled within games, and, in general, modding games themselves is a higher level of abstraction than the focus of this paper.

After the privileging of high art, the vernacular surrounding the decorative arts of rural pre-industrial country craftsmen was unfavorable until the late 19th century, when it took on the perception of being “unpolluted” and “authentic” when compared to mass-produced goods [ Dormer 1997 , 31]. The common opinion of handmade items has oscillated between these favorable and unfavorable views for the last century. In, Andrew Wanger speaks of the 60’s and 70’s “hippy counterculture,” how 80’s and 90’s artists distanced themselves from hippies by focusing on galleries and museums, and today we have another DIY resurgence [ Levine and Heimerl 2008 , 2–3]. Debbie Stoller intraces a more nuanced history of knitting in particular: how each generation either snubs the “silly domestic work” or takes up the needles through necessity or pride, such as in times of economic hardship or war [ Stoller 2003 , 13]. Some alternative terms we have heard refer to this DIY resurgence include maker practice or maker movement, hacker culture, and appropriation of handicrafts [ Tanenbaum et al. 2013 ].

In the West, roughly since the Renaissance when Academies were being created, the five fine arts of painting, sculpture, architecture, music, and poetry became privileged over other artistic professions [ Dormer 1997 , 27]. Other arts, which Greenhalgh calls decorative arts, were considered by some to be too functional or made of too-cheap materials for the designation of fine art [ Dormer 1997 , 29]. Games often use the signifiers of high art, usually easels, paint brushes, or tubes of paint, to unequivocally represent creative or artistic endeavours, such as(see Figure 2). The modern resurgence of DIY (Do-It-Yourself) culture and the indie (independent) craft movement celebrate all forms of art high, low, and undiscovered [ Levine and Heimerl 2008 ]. The wide variety of crafting systems this paper discusses aligns with the indie view and includes high art, decorative art, and creative skills that may have no real-world equivalent.

Paul Greenhalgh separates the history and characteristics of craft history into three threads: decorative art, the vernacular, and the politics of work [ Dormer 1997 , 25]. These attributes cover the split between art and craft, public opinion of handmade goods over time, and the connection of crafts to mercantilism and the economy, all of which have affected crafting representations in games.

Operationalized and systemic representations of crafting, like those found in games, are necessarily in dialog with cultural conceptions of real-world crafting, which is a contested subject in and of itself. To better understand what would cause a developer to declare a system a crafting system, or to build an implied crafting-like system, we examined how crafting formed and exists today in the real world.

Unfortunately, we lack solid definitions of craft systems as this paper refers to them. [ Tychsen and Hitchens 2009 ] and [ Consalvo 2009 ] refer to “crafting” as reference to the colloquial category of crafting professions/skills/jobs in MMOs, and [ Leung et al. 2014 ] is a patent for a “Crafting system in a virtual environment” that attempts to define their use of “crafting systems” with the following:This broad definition, while attempting to enumerate some materials and end products, describes the patent’s crafting system, not crafting systems in general, nor crafting systems within games. Without clear definitions of crafting systems suitable for game studies, we surveyed a broad spectrum of games, including explicit and implicit crafting systems, to find our dimensions of a crafting system: Recipe Definition, Fidelity of Action, Completion Constraints, Variable Outcome, Recognition of Outcome, Player Expressiveness, and Progression (see Figure 1). These dimensions will be fully developed in the core of the paper, Definition and Dimensions of Crafting in Games, following our examination of real-world crafting as a basis for the cultural understanding of crafting systems in games.

Provided herein is a crafting system that allows users or players of a website to create their own “unique” virtual items for use on the site. With the crafting systems, players can collect materials from within a virtual social environment to customize items, which the player can use to express their individuality. Crafting can include materials such as, but not limited to, textiles and related finishes, edible materials, paint, as well as clay, stones and other earthen and organic materials to create pottery. Crafted items include but are not limited to clothing, shoes, accessories, jewelry, food, beverages, dishes, ceramics, paintings or other forms of artwork and designs and furniture. [ Leung et al. 2014 ]

Those experiences that are too far off of the canonical game to count as a game still have a place on Juul’s model. Readers can argue that free-form play should count as a borderline case because free-form play can spontaneously contain many of these game features. In making that argument, readers such as [ Deterding et al. 2011 ] and [ Myers 2009 ] are using Juul’s features and critical language to dissect and analyze games regardless of where they ultimately land on the graph. Juul admits that his model “is no longer all there is to games” [ Juul 2005 , 53]. We understand that our model is also not all there is to crafting systems. However, Juul understands his model is an abstract tool, “an abstract platform upon which games are built, a platform that games use in different ways” [ Juul 2005 , 54]. We see our work, following Juul in outlining dimensions, as a new foundational and abstract tool by which to examine crafting in games.

In the book, Juul evaluates seven definitions of “games” and synthesizes a single definition that he terms “the classic game model” [ Juul 2005 , 23]. This definition is intended to apply to all “traditionally constructed” games from different cultures and across the 5,000-year history of games. In order to accomplish this, Juul surveyed game definitions to extract concepts necessary to all games:After synthesizing seven different scholars’ previous definitions of games [ Juul 2005 , 30], Juul derives six common features to compose his own definitional framework: fixed rules, variable outcome, valorization of outcome, player effort, player attachment to outcome, and negotiable consequences [ Juul 2005 , 36]. Juul uses these features as measuring sticks to determine how game-like an experience is. A game has all of these features, while experiences like gambling or open-ended simulations are borderline cases, and even looser experiences like storytelling or free-form play are simply not games. Some features are binary, such has alternative ending in an experience counting as not having a fixed outcome. However, whether that uncertainty is based on skill, luck, or how impactful it is on the experience of the outcome may be lost.

[A] good definition should describe these three things: (1) the system set up by the rules of the game, (2) the relation between the game and the player of the game, and (3) the relation between the game and the rest of the world. [ Juul 2005 , 28]

This list is by no means exhaustive, but gives an idea of how taxonomies are often used in games studies: to talk about games as a whole and players of particular kinds of games. In only a few cases, we can see categorizations of design approaches that can be similar to a taxonomy, such as Lewis’ collection of motivational design strategies [ Lewis 2014 ]. Individual game systems are less likely to be the focus of a taxonomy, and we focus on one particular game system: crafting.

Taxonomies have also been brought to bear to try to understand the people that play games, instead of games themselves. Bartle breaks players into four types: achievers, socializers, explorers and killers [ Bartle 1996 ]. These four types sit across two axes: whether players prefer action or interaction (the first) with other players or the game world (the second). Similarly, Yee also talks about player motivations in online games [ Yee 2006 ]. Yee breaks down player motivations into three primary categories (achievement, social and immersion) and ten subcategories. In a meta-analysis, Smith et. al. present a taxonomy of player modeling approaches, such as examining whether the player model is general or specific, or categorizes based on human reactions or game actions [ Smith et al. 2011 ].

Shubik also breaks apart free-form games and rigid rule-based games, but additionally considers how the game teaches concepts to the player [ Shubik 1983 ]. Klabbers builds a taxonomy of games by combining concepts from social systems theory with a semiotic theory of gaming, dividing agents in game into actors, rules and resources, each with their own syntax, semantics and pragmatics [ Klabbers 2003 ].

Callois uses a two-dimensional system to classify games [ Callois 1961 ]. The first one is built around four categories: Agon, Alea, Mimicry and Ilinx. Agon refers competition and balance, with all players having an equal chance of success. Alea refers to luck, with players having little control over the game’s outcome. Mimicry is about pretending to be someone else, and Ilinx refers to the feeling of vertigo and attempting to disrupt normal sensory patterns. Callois’ second dimension is focused on the rule base: Piada, freedom for improvisation, is opposed to Ludus, rules and conventions.

Taxonomies are a common tool in game studies as the medium has rapidly been expanding. Ellington, along with his co-authors [ Ellington et al. 1982 ], breaks games up into three pure types (pure games, pure simulations, and pure case studies), and four hybrids (simulation games, simulated case studies, games used as case studies, and simulation games used as case studies).

Definition and Dimensions of Crafting in Games

We further develop our preliminary definition of crafting in games: crafting in a game is the set of mechanics and interactions by which players thoughtfully manipulate materials to create a new entity in the game world. The entity [7] might be created from scratch, or created by modifying or augmenting something that existed before crafting. The entity may be animate or inanimate, a representative of real-life crafting or some fully imaginary and virtual form of crafting only possible in the abstractions of playable media. Resources are often consumed or transformed in the creation process, but don’t have to be. The mechanics and interactions which comprise crafting include actions and choices that players make during the creation process, [8] and the game system’s immediate responses and mechanical interactions with those actions and choices. Players should enact these actions and choices with the intention of making something, and with the feeling that accompanies, even if they don’t know precisely what the created thing will be. And finally, the creation process and the created entity are explicitly represented in the context of the game world [9]

In this definition, we aim to outline a general game experience for which the following design dimensions may be a useful analytical tool, rather than prescribe a narrow characterization of what crafting in games always is and always will be. Creating virtual objects in games happens in many genres and thematic domains, in both computational and non-computational games, and in dialog with many other game systems. The proposed seven-dimensional framework cuts across these differences, posing questions and design considerations, and mapping the experiential space in a way that a narrow definition cannot. We propose that the wide definition offered above be used as a rough guideline for what games to apply the dimensions to, in order to answer game studies and game design questions more useful than, “Is it a crafting system?”

What follows are descriptions of seven dimensions or axes that characterize and explore the space of possibilities surrounding crafting in games. While similar to Jesper Juul’s dimensions of games, our dimensions will differ from his in that in his system there is a canonical concept of game as exemplified by games like chess. Games that score high on all of his dimensions converge on this canonical concept. In contrast, there is no canonical crafting system, just as there is no canonical real-life craft or way to craft. So there is no position along the dimensions that converges to a canonical crafting concept, no position along any given dimension that is implicitly preferred. Rather, each point on each dimension supports different kinds of experiences and play. Among the 64 systems surveyed and discussed here, some readers may also contest particular examples as not “crafting” systems, according to common game cultures’ understandings of crafting. However, we illustrate that the framework is designed to surface useful discussion wherever players create things in virtual worlds. It is intended to serve as a lens, rather than a box, and is informed but not prescribed by the sometimes arbitrary labeling traditions of different gaming communities. We have sampled a wide enough range of different systems to both stretch the boundaries of our dimensions, as well as illustrate combinations of characteristics that have yet to be implemented as gaming experiences in order to help discover them.

It is important to note that the seven dimensions characterize individual crafting systems, not games within which crafting systems are embedded. Individual games can have multiple crafting systems. Games like Minecraft are so committed to crafting that they have multiple, interwoven playable models of crafting, each of which will have their own characterization along the crafting design dimensions.

We now describe each dimension in depth. While there is no intrinsic dimension order, they are presented here roughly in order of the crafting process as enacted by the player. We begin with qualities that primarily describe the enactments of crafting: Recipe Definition, Fidelity of Action, and Completion Constraints. That is followed by what happens after that process is enacted: Variable Outcome and System Recognition of Outcome. Our list concludes with qualities of the larger game experience within which the player may have enacted crafting many times: Player Expressiveness and Progression.

Recipe Definition 38 A recipe is a representation of the knowledge necessary to transform a collection of game objects (ingredients or raw materials) into a new object. For example (described more below), a recipe for a pickaxe might specify two twigs and two flint as the materials necessary to create a pickaxe. Just as objects such as twigs, flint and pickaxes can be virtually possessed by a player, so too can recipes be possessed, where recipe possession means that the player now possesses the knowledge to perform the transformation from ingredients to produced object, typically represented within the game by providing this transformation as a new player action. 39 The Recipe Definition dimension refers to the flexibility of the ingredients used as input to the crafting process. At one extreme is the strongly defined recipe which dictates recipe ingredients precisely, leaving no room for customization or choice in ingredient specifics. This provides less control for the player, but greater control to the game creator, who can explicitly enumerate all possible craftable objects. At the other extreme are crafting systems with undefined recipes. Such systems use an underlying simulation to determine what happens when objects are combined to create a new object. By not enforcing specific ingredient combinations, this opens more possibilities for experimental and creative play, but reduces the game creators’ control over crafting. Between these two extremes are recipes with some predefined structure that support variability in input ingredients and the resulting created object. Strongly Defined Recipes 40 Minecraft ) than the freeform crafting of undefined recipes. Crafting systems which only support crafting by strict recipe sit at the high end of this dimension. These recipe-based crafting systems effectively force players to follow predetermined links between input and output to craft anything. Strongly defined recipes are so pervasive in games that such systems are more commonly called “crafting” by game designers [ Naasz 2013 ] [ Steinke 2015 ], player communities [ Item Crafting 2017 ], games journalists [ Frank 2016 ], and in-game terminology () than the freeform crafting of undefined recipes. 41 Don’t Starve has several crafting systems, including item crafting, crockpot cooking, and structure placement, which fall at different positions on this spectrum. But the one the game itself calls “crafting” (via in-game text), is a classic example of a strongly defined recipe-based system (Figure 3). For example, to make a pickaxe, the player needs two twigs and two flint in their inventory, opens the tools crafting menu, selects the pickaxe icon, and clicks “build.” The player similarly clicks on other object icons and their “build” buttons to make torches, traps, top hats, crock pots, etc. 42 The recipe for an item never changes, and never allows a range of possible resources to fulfill a single ingredient requirement. These recipes also never vary in their output. If the player selects and “builds” the “pickaxe,” she will inescapably have two twigs and two flint removed from their inventory and replaced with a pickaxe. There’s no notion of contextualized raw ingredients, of different kinds or shapes of wood or stone, perhaps from different parts of the virtual world, which might otherwise be visible in the texture and quality of a pickaxe they were used to create. A crafted pickaxe also isn’t changed by random dice rolls, or by the experience, handiness, or personality of the player or player-character. A pickaxe, or any other item the player makes in Don’t Starve , is the same, whether crafted by a full, healthy, lucid adventurer, or one delirious from hunger and monster attacks. 43 From a designer’s perspective, limiting the otherwise large possibility spaces (as strongly defined recipes do) is practical, both reducing development complexity and tightening authorial control over a player’s experience. Strongly defined recipes have an analog to node-and-link-based hypertext, especially when the result is at first unknown to the player. Performing a crafting action using the recipe is like traversing a hypertext link, where the source text is the set of input ingredients, and the destination text is the output of crafting. That the two “texts” are connected by a “crafting” relationship signals a “part-of” or “transformation” relationship to the player. While many existing games use these links functionally, they could just as easily be made more lyrical and interpretive, in the sense of Susana Tosca’s lyrical links [ Tosca 2000 ]. 44 When the individual recipes of a virtual world are considered together, they can describe the logic and conceptual makeup of the fictional world and its inhabitants. Many of the recipes in fantasy RPGs like World of Warcraft , Skyrim , and Dragon Age are composed of found materials like herbs, minerals, and animal fur, which are transformed into items you’d expect from Medieval European craftspeople. Ingredients in No Man’s Sky recipes are often atomic elements or alien machinery, which are transformed into science fiction space-travel technology. The ingredients of strongly defined recipes tell the player how their character understands and acts in the fictional world. 45 Furthermore, the most important of the strongly defined recipes of a game are often revisited many times during play, and thus solidified in players’ minds and Wiki pages. This recipe-learning through repetition can solidify the meaningful connections of strongly defined recipes, and cause players to see the game world through the subjective lens of their fictional avatars. Parametric Recipes 46 Crafting according to a semi-defined recipe links multiple ingredient sets to the same output, or links a given set of input components to multiple possible results. We call both patterns parametric recipes , or recipes that take parameters of input ingredients. In both cases the player has some options in enacting a recipe, either by being able to choose among multiple sets of ingredients to produce a given object in the first case, or in being able to produce multiple objects given a set of ingredients in the second. 47 An example of parametric recipes is the Don’t Starve crockpot cooking system. The crockpot is a crafted structure placed in the world, which itself is a crafting station for producing food items. The player navigates to it, clicks on it, fills the four available slots with individual ingredients, clicks “cook,” and waits for the result to appear in the pot. Crockpot cooking is recipe-based because each combination of four ingredients placed in the slots is linked to an output according to hand-authored connections (where order of the four ingredients doesn’t matter), but the recipes are templated. Each one allows multiple different ingredient combinations for the same output. For example, the Stuffed Eggplant recipe calls for one eggplant, one vegetable food item, and two fillers (Figure 4). The eggplant requirement can be fulfilled by two different single items (eggplant and cooked eggplant), and the vegetable and filler can be fulfilled by 25 and 52 different items, respectively. In effect, Stuffed Eggplant can be produced in 2x25x52x52 = 135,200 different ways. 48 Though the dish is the same, whether made with twigs as filler or with meat, the space of possible input gives the player potentially interesting choices to make in enacting the recipe. She can execute the recipe strategically, using the most widely available or lowest valued ingredients in the set of options. A strategic enactment of Stuffed Eggplant would be to use twigs, a low-risk, readily available, widespread resource in the world, before meat, which is usually risky, rare, and more productively used in other recipes. And the player can adapt her enactment according to what she has an abundance of at the time. But she can also enact it in support of more self-expressive play, which can be encouraged or discouraged by other aspects of the game’s design and the context of crafting. For example, the player can use less efficient ingredients even when there’s an option to use others, if the less efficient ingredient suits their specific play style or desired experience, particularly in terms of role-playing, perceived realism, or exploration and experimentation (see Player Expressiveness). Furthermore, defining a recipe as a space of input, rather than a single possibility, changes the way the player thinks about their crafting. The player can see resources in the world as classes of ingredients connected by abstract properties, and, similarly, interpret crafted entities as the union of abstract properties that define their input parameters. 49 The second kind of parametric recipe is one which represents, rather than ignores, the individuality of ingredients in an enacted recipe’s result. There is still a space of possible input, like the multiple options of many Don’t Starve crockpot recipes, but now the choice among those options is represented in the output. Consider, for example, the Minecraft pickaxe (Figure 5). The player arranges materials in the same, T-shaped graphical recipe to craft any pickaxe in the game. The handle is always formed by two vertical sticks, but the head can use several different kinds of blocks, with the different materials contributing different strength and durability values for the resulting pickaxe. The pickaxe recipe, in effect, is parameterized by those materials. The pickaxe isn’t completely defined; the player has room to enact the recipe in different ways. But, unlike for Stuffed Eggplant, different ingredients produce observable changes in the resulting item. 50 Considering games as a “series of interesting decisions” [ Meier 2012 ], this kind of parametric recipe affords the player crafting decisions which are arguably more interesting and impactful than the previous form of parametric recipe. The decisions she makes in enacting a recipe are visible and significant to gameplay as long as the crafted item exists or is in some way simulated in the virtual world. A player’s choices are made tangible in the very tools she uses, items she carries, and structures she adds to the world. 51 As the constraints of a recipe are relaxed, the closer the experience of following it resembles the freeform mode of creating described in the next subsection. And the closer the crafting experience is to this freeform, experimental mode, the greater the crafter’s agency and expressive potential, the less the authorial control of the recipe-writer, and the larger the impact of the player’s choices on the output and player’s experience [10] Systems with Undefined Recipes 52 Crafting systems without well-defined recipes sit at the low end of this dimension. Instead of explicitly mapping specific crafting inputs to specific outputs, these systems tend to specify rules by which a player can craft, with the results determined by the interaction of those rules. For example, Minecraft block placement (different from the grid-based crafting used to craft a pickaxe) allows players to attach solid cubical blocks to each other along a three-dimensional grid, as long as there is another solid surface in the world to attach them to. 53 Combining components without a recipe is more akin to real-world art-making than real-world cookbook-following. A given set of components may be combined in many different ways to produce many potential results. There is not a hard-coded link from input to output but, rather, a large space of possibility reachable from a given set of input components. Players can create things that are individual and perhaps even unique, if the possibility space is large enough. They can express themselves through crafting; they can take actions and make choices that not all — and sometimes not any — other players will make. Players can create things that surprise even the developers. For instance, because water can be poured into holes and is subject to abstract liquid mechanics in Minecraft , players have invented endless title pools that their avatars can ride in perpetually, without movement input from the player (Figure 6). These “AFK pools” have become popular ways to prevent servers from automatically logging players off for extended idleness (AFK standing for “Away from Keyboard”). In Terraria , obsidian farms and slime machines are often crafted by players to automate particular resource gathering. Freeform crafting systems often sustain large gaming communities of inventive in-game crafting. This kind of inventive play is one of the primary draws of games like Minecraft , Terraria , Besiege , SimCity , Kerbal Space Program , and Draw Something . 54 SimCity Effect [ SimCity Effect. Especially in the AFK pool and obsidian farm examples, players are inventively crafting with the mechanics of the larger game systems in mind. One of the hallmark affordances of crafting in games is that crafted output exists in a virtual world, interacting with the other systems in the game to varying amounts (see Recognition of Outcome). It becomes part of other game systems, influencing world variables and the behaviors of other objects, while they, in turn, influence and act on the crafted item. When Recognition of Outcome is high, players need an understanding of the operations of the game system to be able to intentionally control it through crafting. This understanding, described by theEffect [ Wardrip-Fruin 2009 ], is iteratively developed from player expectations, experimentation, and observations during play. Freeform crafting allows players to test and refine their expectations of system behavior in a unique way, by making them material. Indeed, crafting in systems with undefined recipes and high Recognition of Outcome supports the player learning and iterative mental model-making of theEffect. 55 Draw Something ’s drawing system is so freeform that the player is visible in what she crafts, through her virtual brush strokes, art style, and chosen subject. There is also great variation in how players draw the same item for a friend to guess. And there are often unintended flaws, which means that Draw Something supports the workmanship of risk, as well as aesthetic diversity, in its virtual crafting [ Low recipe definition also allows for crafted objects with individuality — that express aspects of the process and the person who created them — a quality commonly valued in real-world crafts [ Pye 1968 ].’s drawing system is so freeform that the player is visible in what she crafts, through her virtual brush strokes, art style, and chosen subject. There is also great variation in how players draw the same item for a friend to guess. And there are often unintended flaws, which means thatsupports the workmanship of risk, as well as aesthetic diversity, in its virtual crafting [ Pye 1968 ]. This individuality is nearly impossible for a player to express in a strongly defined recipe. 56 Players can improvisationally create within an undefined-recipe system, but also share their inventions and borrow from others through social venues external to the game. They essentially define their own recipes that other players can follow, enabling the kind of socially embedded creativity that is characteristic of real-world crafting communities (see Social Aspects).

Fidelity of Action 57 One concept of psychology that game designers take advantage of in their trade is the idea of affordance as the possibility of an action on some other entity. Buttons beg to be pushed, and tea cups suggest being held by their handle. Affordances [11] are a core component in leading a player to perform particular actions within the game world: pickaxes are used for mining, and sewing machines sew fabric. Fidelity of Action represents how detailed those player-performed actions are within the game world, how accurate those actions are to applicable real-life actions, and how embodied the player performance of those actions is. We reiterate that there is no moral judgement or criticism of a game’s design on how well or inaccurately a game represents their chosen affordance. 58 As an example, consider the representation of knitting in games. In real life, a knitter performing the craft uses manual dexterity to manipulate a continuous thread on two sticks called needles, which produces a knit fabric. The act of knitting has been represented in games in a wide range of fidelity that stretch across this dimension. Knitting Simulator 2014 is an example of extremely high fidelity to knitting because it involves embodied knitting, the player physically mimicking the act of a knitter, on custom game controllers consisting of knitting needles with motion sensors. Each wiggle of the knitting needles represents stitch progress in the game. A game with less fidelity in the knitting genre would be Crafting Mama on the 3DS. Without any controllers representing the knitting needles, the player’s embodied action while playing the game is tapping the stylus on the Nintendo DS screen, which is further away from those in Knitting Simulator 2014 and from real-life knitting. However, the player does tap the screen rapidly to progress stitch-by-stitch, and in traditional Mama fashion, she judges your performance at the end, and you can even dress up Mama in your scarf. The knitting mini-game in Crafting Mama is still very much about the act of knitting. Games with the lowest amount of fidelity in their crafts abstract away the process and leave nothing but a progress bar and/or an end result. For example, a tailor in World of Warcraft ( WoW ) makes fabric, using nothing but fiber, at a click of a button. It could be a woven, knit, or even felted fabric; the player’s character could be using knitting needles, a loom, a crochet hook, or some other tool. We just don’t know. The fidelity of fabric-creation in the case of WoW is extremely low, so low that we cannot distinguish the process as knitting. The Applicability of Fidelity 59 Custom arcade machines, the Nintendo Wii system with its Wii-Mote and Nunchaku, the Playstation Move and its Motion Controller, Microsoft’s Kinect, and other games and systems with custom hardware such as Rock Band have all helped explore the space of high-fidelity experiences. These experiences have so far focused primarily on musical instruments, combat, or other physical tasks, such as requiring accurate aiming with a “gun,” slicing with a “sword,” or placing feet in dancing (Figure 7). Some crafts, such as knitting described previously, are also physical. However, some crafts, and especially design activities and planning, are not primarily performed via physical actions. Accuracy of Abstractions 60 In SimCity (2013), where players craft a city, is the player a mayor, an urban planner, or an urban engineer? Real-life incarnations of these jobs cannot plop down miles of road at a click of a button, or evict a neighborhood of high-class citizens, rezone the district, and instantly create a casino in its place. However, some aspects of the city such as traffic, pollution, hospital access, and water and power systems are more deeply simulated, and the management actions with respect to these city aspects are higher fidelity. Thus the Fidelity of Action of SimCity is quite low in some cases, much higher in others, and so we consider it to have a middling score for this dimension as an average. Completely Fictional Crafts 61 CodeSpells or items in the Atelier series. In these cases, we judge the fidelity of the crafting system’s process by the game’s descriptions of that process, as well as player’s fidelity in enacting those processes. We cannot compare the accuracy of the outcome because there is not a real-life equivalent. In CodeSpells, the player writes code to create spells for their avatar to execute, including effects over time, changes to the environment, and visual elements, such as particle effects. As the game is made of code and exists by executing code, we determined there was no greater fidelity for a digital fictional system other than programming its behaviors. Some developers design a completely fictitious crafting system and/or crafted items for their game’s mechanics, such as spells inor items in theseries. In these cases, we judge the fidelity of the crafting system’s process by the game’s descriptions of that process, as well as player’s fidelity in enacting those processes. We cannot compare the accuracy of the outcome because there is not a real-life equivalent. In [12] the player writes code to create spells for their avatar to execute, including effects over time, changes to the environment, and visual elements, such as particle effects. As the game is made of code and exists by executing code, we determined there was no greater fidelity for a digital fictional system other than programming its behaviors. 62 In contrast, the Atelier series describes the process of alchemy as partially physical. Alchemy, in this case, is a fantastical incarnation of the real-life profession, which involves mixing loosely related materials in a special cauldron to produce everything from potions, baked goods, equipment, and even living creatures. In Atelier Totori , the protagonist is often shown learning how to stir contents of an alchemy cauldron in a particular manner. However, while each Atelier game involves different alchemy minigames as the primary gameplay and progression mechanic, none involve stirring or embodied action with the cauldron. The player progresses through a series of menus, managing ingredients, item properties, and alchemical skills, but the player never learns the details of how the alchemist makes the final product. While the process of alchemy is intricate in many areas and offers extraordinary depth in its menus, it fails to fully model all the aspects of the craft it created, and so the series is slightly above average on the Fidelity dimension.

Completion Constraints 63 Everything that is required for an entity to be crafted is encapsulated within this dimension. For the general crafting process, resources are usually consumed, perhaps some tools are used (what we call required components), and time passes to indicate the transformation of resources to the end product. Sometimes a game might impose other restrictions on the player, such as only being able to have two professions in World of Warcraft , what we discuss below under miscellaneous constraints. While this paper does not address systems outside of crafting, such as prerequisite resource-gathering, the use and consumption of resources or tools heavily influences a player’s crafting experience. Designers often use resources or recipes to gate progression, require crafting stations to pace gameplay, or consume player time as a function of gameplay. 64 The completion constraint categories are also problematic upon further inspection: there are many systems that use no resources, some games with legal tender that make differentiation between resources meaningless, and the concept of time is not consistent between systems. Given the breadth of systems and mechanics, the subjective difficulty of these constraints, and the often compounding influence of these constraints due to crafting trees, it became impossible to objectively compare the impact of the different types of constraints between systems. 65 Instead, we largely took a quantitative approach of how many different types of constraints were involved in the crafting process (resources, time, location, and peripherals), with the presence of miscellaneous constraints and the severity of the constraints nudging games that fell within the same number.of types of constraints (Figure 8). For example, systems with resources are more constrained than those that do not use resources, but resource systems that have a legal tender that allows for resource trade are less constrained than those resource systems without. In general, the higher the score, the more disparate conditions the player must satisfy in order to complete crafting. Consumed Resources 66 EVE Online , Lichdom spellcrafting, or Wildstar gear crafting). Any prerequisite material with a limited durability, in that some part or whole of the material is removed or destroyed during crafting, counts as a consumed resource. Thinking about games in terms of how these resources flow, how they are acquired and spent, has a history in game analysis. For example, Dorman’s Machinations is a way to describe arbitrary game mechanics in terms of resource flows [ Games often deal with consumed resources — currency or materials players acquire that can be spent in order to achieve certain goals in a game. Consumed resources may also include the recipe itself as a blueprint object and is actually consumed to craft an item (such as inspellcrafting, orgear crafting). Any prerequisite material with a limited durability, in that some part or whole of the material is removed or destroyed during crafting, counts as a consumed resource. Thinking about games in terms of how these resources flow, how they are acquired and spent, has a history in game analysis. For example, Dorman’sis a way to describe arbitrary game mechanics in terms of resource flows [ Adams and Dormans 2012 ]. 67 However, not all crafting systems have consumed resources. Knitting Simulator 2014 , where the player goes through the actions of knitting, does not consume any resource. Players do not spend anything to make a new stitch. In general, when players play with crafting systems in free-play modes (where they are presented with an unlimited amount of resources that are always present), it becomes challenging to consider crafting systems as only resource transformation systems. Present Resources 68 Materials or tools that are not consumed, but are still required to be present in an inventory or game world, are considered present resources. We bother with the distinction because present resources are a one-time need that is more flexible than consumed resources. A jeweler’s kit is required to be held by jewelcrafters in World of Warcraft for them to create gems and jewelry, but so long as they have that item, they can craft at any location in the world (Figure 12). While economies are often deeply integrated with consumed resources, present resources, other than possibly first acquisition, are separate from the influence of currency. 69 Once the player acquires access to a present resource, it often opens up a whole new set of recipes in crafting progression. For example, the hellforge is a crafting station in Terraria that can only be found in the underworld (but it can be picked up and carried back to the player’s base). It can smelt some of the most powerful pre-hardmode materials and can be used as a consumed resource to create the first forge able to smelt hardmode metals, helping unlock two new tiers of player strength. A crafting tree that combines consumed and present resources for a Terraria item is shown in Figure 9. 70 The constraint of present resources is kept separate from location constraints because, as in Minecraft ’s or Terraria ’s crafting stations, they can sometimes be picked up and carried with the player, functionally removing the location restriction that other systems may enforce. Time 71 Time is a complex topic in games. According to Zagal & Mateas, there are four common temporal frames: real-world time (experienced in the physical world), gameworld time (in-game time including events around gameplay action), coordination time (coordination between player and agents, such as navigating menus), and fictive time (acknowledged sociocultural labels and event sequences) [ Zagal and Mateas 2010 ]. Sometimes, crafting takes time in any of these temporal frames. This slows down a player’s completion rate, either because crafting comprises a game in and of itself which takes time to play, or players just need to wait a certain amount of time before the crafting is finished (in real-world time or gameworld time). However, not all time is created equal. Some crafting delays take up all of the player’s focus and ability to perform other tasks, while other delays are completely idle. 72 In Final Fantasy XIV: A Realm Reborn , a player must spend time performing a sequence of crafting actions to complete a craft, during which time the player cannot perform other gameplay actions without abandoning the crafting sequence (Figure 15). When romancing piñata animals in Viva Piñata , the player has a skippable cutscene, but a non-skippable minigame to play. Macro engines (discussed later in Automation) allow a player to remain attentive of other things as the performing of crafting actions is automated, but she still needs to wait for crafting to complete. In the same vein, players cannot act while waiting for a bar to fill to complete a craft in World of Warcraft , although this sort of delay does not require intense player focus (Figure 10). 73 Time, when considered this way, is a hard, unskippable constraint. Besiege does not have this constraint, because the player can complete crafting her fantastical steampunk death machine by just clicking go. Further, Besiege starts players with a core ‘starting’ block, and considers this starting block a valid, completed craft; thus, players do not have to make any crafting decisions in any temporal frame in order to immediately begin playing the game In contrast, in Final Fantasy XIV: A Realm Reborn , the player must execute a series of repetitive actions in order to fill a completion bar to create a craft (Figure 15). 74 Pokémon breeding. Time, as measured in the number of steps the avatar has taken in the game world, is a large delay in breeding a new Pokémon. Although the player is free to perform other in-game tasks while she waits, time only passes — at least in relation to waiting for pokémon to breed — when the player avatar moves. This is different from the time constraints in [13] breeding. Time, as measured in the number of steps the avatar has taken in the game world, is a large delay in breeding a new Pokémon. Although the player is free to perform other in-game tasks while she waits, time only passes — at least in relation to waiting for pokémon to breed — when the player avatar moves. 75 Both these examples are different from how time is considered in Eve Online ’s manufacturing system. Time in Eve Online’s manufacturing system heavily involves the real-world temporal frame and is directly tied to the passage of real-world time outside the game — a manufacturing job is measured in a number of minutes, hours or even days (Figure 11). A player does not have to be playing the game for that entire amount of time. Progress on completing the manufacturing job happens regardless of the player being logged in. Location 76 Typically, only a concern when a player is embodied, some games require a player to be in a particular gameworld location to craft items. Not all locations serve as meaningful completion constraints, however. Kerbal Space Program has specialized hangers where a player builds rocket ships and space planes, but a player can snap to these locations at any time (even in the middle of a rocket launch). Thus, they provide a thematic frame for construction (construction happens in hangars), but don’t introduce an actual gameplay constraint within the crafting system. Systems that include more thematic and less functional location constraints receive a smaller score than those with immobile, hard location constraints. Examples of gameplay location constraints include workbenches in Minecraft , cooking fires in World of Warcraft (Figure 12), or the non-player character (NPC) craftspeople a player visits to craft weapons, armor, or gems in Diablo III . 77 It is important to note that locations can also represent available land for construction, in games where the player is crafting some physical space (e.g., creating a pond or fencing in a garden space in a Viva Piñata garden). Although the player isn’t really embodied in Viva Piñata , she still needs to maneuver the camera to an unoccupied place in the game world before being able to complete a crafting step of planting tree or building a fence. Miscellaneous Constraints 78 World of Warcraft , player characters are limited to two professions; each profession limits what the character can and cannot craft. Some professions have further specializations, such as World of Warcraft engineers being able to choose between gnomish or goblin engineering. To get around this constraint, players often have more than one character, each with a different set of professions. These alternate characters (alts for short) allow players to maximize their crafting output [ In addition to consumed resources, present resources, time, and location, there are other miscellaneous constraints that are occasionally used in crafting systems. For example, in, player characters are limited to two professions; each profession limits what the character can and cannot craft. Some professions have further specializations, such asengineers being able to choose between gnomish or goblin engineering. To get around this constraint, players often have more than one character, each with a different set of professions. These alternate characters (alts for short) allow players to maximize their crafting output [ Consalvo 2009 , 413]. But time, location and resources account for the vast majority of constraints found in crafting systems.

Variable Outcome 79 Crafting systems are not always deterministic paths representable by a crafting tree. Two players can have the same tools, have the same resources, be at the same location, take identical actions, and still end up with two different results. We refer to this randomness as Variable Outcome. 80 Variable Outcome is not the same as having visible variables in a crafting system. Rather, fixed or random variables may be hidden from the player; this requires a player to explore the system in order to unveil the rules under which the gameworld operates. Players may develop a “feel” for the values a stochastic variable may take. Crafting systems often allow players to manipulate the probability distributions of their random variables, increasing the odds that they will get the outcome they want. For example, in World of Warcraft , whether or not crafting a particular recipe will help level up a crafting stat is random. However, certain recipes at a given cooking skill have a higher probability to give further stat increases and are color coded to show this to the player (Figure 13). By only crafting particularly colored recipes, the player is putting a thumb on the “increase crafting stat” variable and pushing it in her favor. 81 Randomness in a crafting outcome can sometimes include a complete failure to craft, or randomly assign properties to a completed item. An item can be of better or worse quality. Or the process may refund a variable amount of resources back to the crafter upon completion. 82 A common paradigm for games is to randomly apply some extra properties to a crafted item, with some of them being negative. Each act of crafting always produces something, but it might not be exactly what the player is looking for. 83 For example, when crafting a new weapon in Terraria , players combine various resources at a particular location in the game world. Part of this is deterministic; players will always get a particular weapon with certain default characteristics. However, the weapon also gets a random modifier that is outside the player’s control. This modifier can impact the effectiveness and utility of the weapon at hand, shown in Figure 14. 84 There is no way to control the random selection of a modifier; a player cannot make particular modifiers more or less likely. Terraria does allow for a player to reroll a modifier after a weapon has been created as many times as she likes until she happens on the desired one. For variable outcome, this is a common design choice — if a player can’t have control over an aspect of crafting, at least she can retry somewhat easily in order to find the values she wants. Variable Outcome is Uncommon 85 Variable outcome is not particularly common, especially in systems built for simulation. Most of the crafting systems analyzed do not have any variable outcome. The spaceship manufacturing in Kerbal Space Program is typical of the common case of completely deterministic crafting. Players have complete control over how the parts are placed on their spaceship, and how those parts will function. The player has absolute control over the form and function of each new spacecraft she creates. This helps reveal the underlying rules of the world to players via the crafting system. It is more difficult for players to form a mental model of the crafting system when it contains hidden variables or is intrinsically stochastic. Variable Outcome in the Real World 86 Linking variable outcome back to real life crafting, it intuitively feels like a proxy for the random forces that impact successfully completing a craft in real life. Think of the random forces that impact successfully making a dish in a kitchen — a cook can accidentally add too much of an ingredient at a particular time, grab the wrong spice, or have the lid of the spice container come off while shaking some into the dish. However, Variable Outcome in game crafting systems leads to different effects than the variability in real life crafting. 87 In the Workmanship of Risk (see Aesthetic Diversity), Pye argues at length about the virtues of workmanship and how it relates to design. Items created with unregulated or free workmanship often look very different from each other, but can serve the same functional purposes. In addition, they can be of the same quality, even if they look very different. This kind of variability relates to the improvisational skill of the craftsperson given the dynamic richness of real-world situations. In contrast, variable outcome in game crafting systems often works against Pye’s dream of aesthetic variability. Given the stochastic modeling of object attributes typical in crafting systems with variable outcome, the results are often not functionally equivalent — they vary along attributes with gameplay significance, making one crafted object clearly superior to the other. 88 Either due to internal motivation, social pressures, or other forces such as gameplay thresholds, players often look for optimal items. These players grind until they get the optimal bit of gear, repeating the crafting attempt as many times as it takes until the outcome lines up with their definition of optimal. Variable outcome, in this case, doesn’t actually improve the aesthetic diversity of various crafted items in games. 89 This actually makes variable outcome, in the games we analyzed, a poor proxy for the random forces that impact real-world crafting. A missed stitch, awkward tension, or a flaw in the yarn does not meaningfully change how warm a sweater is. However, this type of improvisational variability that free workmanship has been under-explored in crafting systems and is a rich future direction for crafting system design. Progression with Randomness 90 Gaining influence over a random variable is a way to add progression into a crafting system, which sometimes ties this dimension to Progression. As players progress in the game (sometimes within the crafting system, and sometimes as part of a different system), players may get new ways to view the random variables at play or the ability to narrow the ranges on the random variables. 91 This is one of the primary ways players progress in the crafting system of Final Fantasy XIV: A Realm Reborn ( FFXIV ). FFXIV ’s crafting system is complex, giving the player a range of crafting actions that are abstractions over ideas and concepts that ground out in real-world crafting (e.g. “Precise Touch”, “Muscle Memory”). Some of these skills fill up a progress bar, and when the bar is full, the item is created (see Figure 15). 92 However, in Figure 15 we can see items also have a running durability score, which represents how many more actions can be performed before the crafting is forcibly resolved. Finally, there is a quality bar, which is the chance that, when the craft is completed, the item produced will be of high quality (better in terms of stats). In addition, randomly, the next action taken can be flagged as excellent, good, normal or poor, which impacts the rate at which the progress and quality bars fill. This random action bonus or penalty is referred to as the action’s condition. 93 Starting crafters in FFXIV are at the mercy of conditions — without a few lucky successful actions while avoiding an unlucky failure, the progress bar cannot be filled and the craft fails. However, as players progress, they unlock more crafting skills which gives them more control over the crafting process. A ‘poor’ condition becomes less of a setback, an ‘excellent’ condition can be capitalized on. Likewise with the quality bar — at the start, players have very few ways of filling the quality bar, or can fill it, but at the expense of being able to fill the progress bar. As players progress, filling the quality bar becomes more feasible, and players can more consistently create items of high quality. This mastery of randomness is pleasing and powerful, and one case study into how Progression can work in a crafting system. Recipe Definition with Randomness 94 While attempting to visualize the range of inputs that could be part of the Recipe Definition, Completion Constraints, and how they related to the variability of the outcome, we created Figure 16.

System Recognition of Outcome 95 System Recognition of Outcome refers to the manner and degree to which a larger game system models and represents the results of crafting. This is the reinforcement after player’s crafting actions by which players know that they have crafted something; that something new exists in the virtual world as a result of their decision-making and actions. System recognition ranges from one-time, immediate graphical or textual acknowledgement, to complex behavioral modeling of the crafted item over time. 96 The level of system recognition of a crafting system may be estimated by answering these questions, adapted for crafting from Chris Crawford’s listen-think-speak definition of interactivity [ Crawford 2003 ]. How many properties of the resource constraints and crafted output does the system use to impact future game actions? How much processing, or transformation, does the player perceive to be carried out on those properties? Do those properties change the final product or how the final product interacts with the greater game systems? How deeply is the output of crafting represented to the player? Can the player perceive the transformation by some textual, graphical, or other signal expressed by the final product? 97 These questions culminate in how well a crafting system (1) listens to, (2) thinks about, and (3) speaks about what a player is crafting and has crafted. In Crawford’s terms, it is how well the system holds up its end of the conversation with the player, after the player has “spoken.” In this case, the player spoke through crafting actions, and the focus of conversation is on what the player has crafted. If the system looks at few properties of the output, processes them minimally or not at all, and presents that minimal processing directly, without impacting other game systems, it is considered to have low system recognition of outcome. If the system uses many properties of crafting output, connecting crafting output to non-trivial functions and other game systems, and presents a transformed representation and cascading consequences of the output back to the player, it has high system recognition. Low Recognition 98 Kittens Game , crafting a stone slab results in a slab counter in a list of many other counters quietly increasing, or a new counter quietly appearing if it hasn’t been crafted before (Figure 17). Such counter-based representation of crafting, in which the sole purpose of crafting objects is to increment counters which then serve as resources for crafting other objects (which are themselves just counters), is typical of the idle games (or incremental games) genre [ Among the lowest modes of recognizing player crafting is by direct, one-time acknowledgement by static text or image. In, crafting a stone slab results in a slab counter in a list of many other counters quietly increasing, or a new counter quietly appearing if it hasn’t been crafted before (Figure 17). Such counter-based representation of crafting, in which the sole purpose of crafting objects is to increment counters which then serve as resources for crafting other objects (which are themselves just counters), is typical of the idle games (or incremental games) genre [ Khaliq and Purkiss 2015 ] [ Deterding 2016 ]. The system uses for recognition only a single property of a crafted item: that the item now exists. It doesn’t need any other information about that item. The only processing over that single property is the incrementing of a numerical inventory count of identical items that existed previously. In the context of gameplay action, the system propagates the consequence of that changed numerical value to other relevant systems (such as trade). The only direct representation of the output is a changed textual counter. 99 The indirect representation of output through other game systems pushes Kittens Game ’s crafting model higher than its otherwise minimal position on this dimension. It further recognizes player-crafted items by modeling them as ingredients in future crafting recipes, and as inputs to the game’s economy, as goods that can be sold or traded. Medium Recognition 100 Contrast this representation with crafting whose output is given physical manifestation in the gameworld, beyond an inventory abstraction. In Minecraft crafting (versus block placement), many craftable items exist as icons in inventory slots, but may also be placed in the world or held and used by the player character. When a pickaxe is crafted, it appears as a static, 2D icon in the inventory menu, that may be dragged and dropped into different slots of a grid. It may then be selected to be equipped, at which point its 3D, voxel representation is visible in the player character’s hand as she moves about the world. With pickaxe equipped, the player can click on blocks in the world, causing the pickaxe’s 3D model to move and rotate with the avatar’s arm, as if being swung. Each click and swing causes cracks to appear on the clicked block, growing more pronounced with each swing, until finally bursting into collectible resources if the pickaxe was crafted with a strong enough metal. Besides the all-important pickaxe, Minecraft crafting supports the creation of other equipable tools, weapons, armor, and several classes of placeable blocks and vehicles. 101 Minecraft easily has deeper recognition of crafting outcomes than Kittens Game , but less than games which, for instance, apply and visualize detailed physics simulations. We analyze this already complex middle case as follows: The Minecraft crafting system recognizes several properties of its crafted items: item category (e.g., pickaxe, sword, wood plank) and several classes of ingredients, which are different for different item categories (e.g., for pickaxes, axes, and swords, the metal used matters; for wood planks, the kind of wood blocks used matters). The system-observed properties of the crafted items are transformed and processed only slightly: for stackable items, an inventory counter is increased, and for items with quality, that quality is compared to the quality of an action target to determine the action’s outcome. When the player uses these different items, their properties are used in determining action outcomes (e.g., if mining with a crafted pickaxe, a block can burst into resources). The crafted items are modeled as moveable graphical icons in a gridded inventory space, as 3D-modeled objects in the world. The material composition (and thus strength) of the item is ‘spoken’ to the player as different-colored versions of the same item corresponding to the color of the material. High Recognition 102 At the highest end of this spectrum are games which save a lot of information about how an item is crafted and use that information as input to a simulation, which applies functions or rules to transform that saved information, and whose behavior may be observed during play. Such simulation-based crafting recognition games include Besiege , Kerbal Space Program , SimCity , CodeSpells , and Spore ’s character creation. 103 In Besiege , players craft hyper-destructive siege machines from a large pallet of combinable engine parts, including beams, springs, flame-throwers, and motorized wheels. The resulting objects often look like they could be Medieval European war technology, but are crafted from atomic parts with a large space of potential combination. Players regularly create mechanisms never used in historical European warfare and that are in fact completely new to Besiege and its online community. In Besiege , recognized properties of a crafted item consist of its types of component pieces (e.g., beams, springs, wheels), and how those pieces are arranged relative to each other in a 3D space (e.g., this particular beam is connected to this wheel in this orientation). The game system represents many physical properties of the constructed entity, excluding only information such as the exact sequence of actions or time the player took to construct it. The recognized properties are transformed by putting their representation through Besiege ’s stylized physics simulation. X- and y-positions of engine parts are modified by gravity, collision with other solid objects, input controls, and the behavior of connected parts and the type of connection. The crafted item is well represented to the player. When the player completes a siege machine, they can press a key or button to “play” the scenario, which exits build mode, begins applying the physics engine to the machine as it is represented graphically, enables keyboard-controllable pieces to be controlled, and initiates the movement and targeting of tiny, defending NPC knights and archers toward the newly minted death machine. Patterns of System Recognition 104 Besiege , with particularly high outcome recognition, the core loop often emphasizes it via a separate, watch-it-run or simulation phase, following the crafting. Often, the phase makes the crafted item more traditionally playable, with movement-control or other minimal interactivity. True also of Kerbal Space Program , Incredipede , and Spore character creation, this affords the player the unique pleasure of seeing her creations theatrically come to life, in a performative reveal after a suspense-building crafting period. The player creates with an idea of what will happen, runs the simulation and inevitably finds her idea only partially correct, but in an understandable way, so that her idea of what will happen is updated to reflect a better understanding of the simulation. Her updated mental model is immediately actionable in the next crafting phase. The game-internal core loop is neatly translatable to the player-internal iterative model-making loop of the SimCity Effect [ Minecraft block placement, supports player embodiment as a character in the virtual world, and is more commonly integrated with larger gameplay experiences that aren’t focused primarily on crafting. Furthermore, systems high on outcome recognition and low on recipe definition generally support the SimCity Effect (named for a live crafting system), regardless of the presence of a detached watch-it-run phase after crafting. In games like, with particularly high outcome recognition, the core loop often emphasizes it via a separate, watch-it-run or simulation phase, following the crafting. Often, the phase makes the crafted item more traditionally playable, with movement-control or other minimal interactivity. True also of, andcharacter creation, this affords the player the unique pleasure of seeing her creations theatrically come to life, in a performative reveal after a suspense-building crafting period. The player creates with an idea of what will happen, runs the simulation and inevitably finds her idea only partially correct, but in an understandable way, so that her idea of what will happen is updated to reflect a better understanding of the simulation. Her updated mental model is immediately actionable in the next crafting phase. The game-internal core loop is neatly translatable to the player-internal iterative model-making loop of theEffect [ Wardrip-Fruin 2009 ]. Further, “live” recognition, that happens in real time, both as the item is crafted and afterward, as withblock placement, supports player embodiment as a character in the virtual world, and is more commonly integrated with larger gameplay experiences that aren’t focused primarily on crafting. Furthermore, systems high on outcome recognition and low on recipe definition generally support theEffect (named for a live crafting system), regardless of the presence of a detached watch-it-run phase after crafting. 105 Other patterns of system recognition include graphical modeling and physics simulation (e.g., gravity, collision, fluid physics), impact on a stats system (combat, character progression, NPC relationships), and adjacency bonuses in base or city-building (e.g. building a Theatre District next to a Natural Wonder in Civilization 6 produces bonus culture). All of these can vary on system recognition by how flat or complex the model is. 106 Another interesting pattern is the use of outcome recognition to identify conditions-based recipes in an otherwise undefined recipe system. In Terraria , houses can be built for NPCs using the general block-placement system, anywhere in the large sandbox world. But NPCs will only become residents if particular requirements are met: blocks are placed to form a fully enclosed structure, with at least one entrance, covering at least 60 total tiles, but less than 750, containing at least one valid light source, flat surface item, and comfort item. The system will check for player structures which satisfy this after crafting, rather than impose the requirements before the structure can be built at all, as in strongly defined recipe crafting. This pattern is also visible in the gardening of Viva Piñata , in which specific clusters of player-placed items and piñata residents in a garden entice other piñatas to visit and become residents. This style of recognition enables both the creative experimentation and expression of freeform crafting as well as the authorial control of predefined recipes. When players discover these implicit recipes, without having looked them up or known about them beforehand, this style of system recognition can be a delightful and surprising meeting of minds between the player and system. 107 Games with undefined recipes often have high system recognition, as with Besiege , Kerbal Space Program , and Minecraft block placement, but this is not always the case. Draw Something has no recipes, yet low system recognition of the player-created drawings. The system doesn’t listen and respond to player input beyond presenting the drawing on the screen as it was drawn. Instead, the finished drawings are recognized by a human partner, in an association game paradigm similar to Pictionary or charades. Player-recognized crafting is not mapped by this dimension, yet features importantly in Player Expressiveness.

Player Expressiveness 108 The dimension of player expressiveness captures the range of reasonable actions and outcomes within a crafting system suggested by the domain of the game world. “Expressiveness” is a somewhat vague term, as is “creativity” (See Craft and Creativity), but this dimension focuses on the amount of reasonable choice the player has, given the game’s setting and the tools provided to them, during the process of crafting. This dimension is not trying to capture players explicitly subverting or exploiting a crafting system, as might occur in counter-play. Further, this dimension is not about the process of choosing what to craft, nor about the uses of the item after being made. For example, this dimension is about the process of customization and sewing of a shirt, not about choosing to wear the shirt (because it may be pretty or powerful), nor about how to dye, alter, or equip the shirt in a different crafting system after being completed. In short, we are ignoring the infinite combinatorial influences of outside systems as much as possible, but we acknowledge that an outside influence can inspire creative action or exploration. We do not care where inspiration comes from; this dimension only measures whether or not the player can express her inspiration successfully. 109 For example, in Draw Something , the player is given a one-word prompt to draw, and she is victorious if the other player guesses her prompt successfully. The player is free to draw anything she likes in a rainbow of colors, whether or not it supports the prompt. The user may draw an expansive beach scene, put Batman lounging in a beach chair with a coconut drink complete with tiny umbrella, and point to the little straw in the cup for the prompt “straw.” While the brushes and drawing tools are extremely basic, players can use fingertips or a stylus to be as creative as they like or spend as much time on a drawing as they desire, and this results in extremely high player expressiveness. 110 Neko Atsume , a game of “gardening” cats via putting down enticing furniture, players don’t have the ability to pet, adopt, customize, or directly interact with the cats, which are common actions players may want to do with real or virtual cats. There is a lack of fulfillment of player desires in customizing their homes or interacting with their cultivated garden of adorable felines, which results in lower player expressiveness. A game world that suggests many creative options without offering the ability to capitalize on them has the lowest level of Player Expressiveness. For example, Knitting Simulator 2014 , which emulates knitting extremely well, offers no ability to change, adjust, or customize yarn color, pattern, or stitches. All of the creative choice a crafter has when knitting is absent. The mechanics of the game distill down to a progress bar, leaving no space for player agency and no support for player choice. In the terms of Mateas, this would be called an imbalance of material affordances (reasonable player desire) and formal affordances (game system support) [ In, a game of “gardening” cats via putting down enticing furniture, players don’t have the ability to pet, adopt, customize, or directly interact with the cats, which are common actions players may want to do with real or virtual cats. There is a lack of fulfillment of player desires in customizing their homes or interacting with their cultivated garden of adorable felines, which results in lower player expressiveness. A game world that suggests many creative options without offering the ability to capitalize on them has the lowest level of Player Expressiveness. For example,, which emulates knitting extremely well, offers no ability to change, adjust, or customize yarn color, pattern, or stitches. All of the creative choice a crafter has when knitting is absent. The mechanics of the game distill down to a progress bar, leaving no space for player agency and no support for player choice. In the terms of Mateas, this would be called an imbalance of material affordances (reasonable player desire) and formal affordances (game system support) [ Mateas 2001 ], expanded in [ Wardrip-Fruin et al. 2009 ]. In these examples, we show that high player expressiveness is a combination of a creative domain or space that begs for customization, as well as mechanical support for the player to create within that space. Subversive Play 111 Overwatch or DOTA, where one player’s cheating harms the play experience for another real-life human. Other developers may embrace and attempt to support subversive play, such as Will Wright, creator of the Sims and a fan of attaching toys to rockets [ Sims game since Sims II . The Sims series of games has many interesting opportunities for subversive play, such as torturing and killing sims in countless ways, flirting with Death, and having babies with aliens [ In real-life situations including games, open-ended play, or law, many humans have cheated, found loop-holes, and otherwise circumvented the rules or intended purpose of rules. Often, cheating leads to avoiding or skipping game challenges by amassing experience, automatically aiming at critical targets, or having unlimited health or lives. However, a subset of creative players cheat or find alternative modes of play within a given arena. Game scholars call these activities “critical” or “subversive” play [ Flanagan 2009 ]. Game developers can try their hardest to snuff out cheaters, and often do in competitive games such asorwhere one player’s cheating harms the play experience for another real-life human. Other developers may embrace and attempt to support subversive play, such as Will Wright, creator of the Sims and a fan of attaching toys to rockets [ Totilo 2010 ]. The “motherlode” debug code, which grants the player a large sum of in-game currency, has existed in nearly everygame since. Theseries of games has many interesting opportunities for subversive play, such as torturing and killing sims in countless ways, flirting with Death, and having babies with aliens [ Reddit 2015 ]. Since choosing to play subversively is a direct choice of the player’s, and a developer’s support of those choices enables players to explore new and creative experiences, games that explicitly support subversive play have increased player expressiveness. This is distinct from unsupported subversive play, which, as we say above, we do not count towards player expressiveness in our analysis. There are very few examples of these games, however, and this is a rich area of potential future exploration. Resources and Recipes 112 Minecraft do not immediately recognize that the positions of materials in the 2x2 and 3x3 crafting grids (discussed previously in Strongly Defined Recipes and Figures 5 & 19) are meaningful. However, once the player discovers this fact, if she doesn’t already know the other recipes, there is an immediate suggested course of action discovered within the crafting grid. Regarding Minecraft ’s other primary crafting system of block placement, different block materials can help crafters better suggest form in their low-resolution sculptures or apply other forms of art, such as pixel graphics. Not only do users have the range of naturally occurring material, such as stone or wood, but they can dye wool in a range of 16 colors. If we examine character customization in Minecraft , we also see that those 16 colors can be mixed or overdyed to create 12,326,391 colors Different materials and recipes often spark new ideas or give avenues for fresh inspiration and methods of crafting. For example, many players ofdo not immediately recognize that the positions of materials in the 2x2 and 3x3 crafting grids (discussed previously in Strongly Defined Recipes and Figures 5 & 19) are meaningful. However, once the player discovers this fact, if she doesn’t already know the other recipes, there is an immediate suggested course of action discovered within the crafting grid. Regarding’s other primary crafting system of block placement, different block materials can help crafters better suggest form in their low-resolution sculptures or apply other forms of art, such as pixel graphics. Not only do users have the range of naturally occurring material, such as stone or wood, but they can dye wool in a range of 16 colors. If we examine character customization in, we also see that those 16 colors can be mixed or overdyed to create 12,326,391 colors [14]