作者：Steve Breslin

“沙盒”现在是游戏圈中的热词。与“自由”或“爱”一样，“沙盒”是一个非常抽象的概念，所以存在诸多变体。现代沙盒游戏借鉴了多种设计结构，比如开放世界设计、突现行为、可信的角色的自动化、多线程或非线性故事，等等。

“沙盒”的运用情形如此广泛，以至于其本身的意义面临被淡化、混淆和甚至遗忘的风险。

另一方面，它仍然是当前和未来游戏的一个最重要的设计问题。所以花一些时间认真地思考这样一个严格界定的概念是值得的。

借此机会，我们回顾一下我们作为玩家和设计师对这个概念的不同看法。当我们展望这个奇妙的小概念的未来时，我们不妨了解一下这整个概念的由来和发展。

首先我们从抽象意义上思考这个概念：

隐喻的反语

我们都知道，沙盒式玩法的概念意味着或多或少地无目的的自由玩法（free-play）。这个隐喻来源于小孩子玩的沙盒：孩子用沙子——最基本的材料建造自己的小世界。这与沙盒游戏的世界是相反的，后者的上层内容是以严格的形式和顺序呈现出来的。

“沙盒”的隐喻暗示着纯粹和自由。它与沙盒中的小孩（这时的小孩没有电子游戏也没有玩具），理想化的儿童幻想和无限的创意有关。这是一个好比喻，也非常实用，但也有一点儿误导，因为它要求受众对梦想世界具有虚构能力，但并不总是合理的。

这个隐喻的含义并不总是被游戏设计师接受：我们认为想象力差的玩家对沙盒游戏的感受会更少，这是无所谓的。但即使如此，利用玩家的想象力的想法仍然相当有野心，不只是有一点儿冒险。

这个设计概念本身就太有野心了——“给他们一个沙盒，他们就会建出城堡”，为了让沙盒确实管用，必须满足更大的投入，这通常意味着在所有生产环节中投入更多钱和时间，特别是上层设计和编剧。这意味着程序和上层设计之间的密切关系，期望上层设计通常决定下层规范。

如果说一般的游戏设计是根据引擎开发上层材料（比如任务等），那么沙盒设计就是编写引擎来表现上层的玩法概念。当然，不可能说得这么简单：确实，游戏生产总是在程序和设计之间往返。

但基本上，沙盒设计需要开发一个允许玩家以各种方式探索游戏世界的引擎，这个引擎还要通过提供能处理沙盒元素的系统来支持上层沙盒设计。这对系统程序员来说是有趣的工作，但并不容易。沙盒需要能突显和鼓励自由玩法的设计，以及开发和执行各种动态互动的元素。

沙盒设计不只是展示沙盒元素和游戏空间，还有处理所有玩家的各种互动活动、所有可能的组合。简单地说，一般的游戏必须对正确的输入作出回应，而沙盒游戏必须对所有输入作出回应。

虽然真正的沙盒玩具是很容易做出来的（与其他玩具相比），但与类似的、开放性更低的、反应性更弱的游戏相比，制作沙盒游戏通常要求更多工作。与做真实的沙盒的人不同，沙盒游戏设计师不可能简单地把创意想法丢给玩家。

必要的框架

不幸地是，有时候沙盒设计被用来为完全相反的概念作辩护：“沙盒”有时候被用作少投入的借口，特别是在上层设计中。沙盒元素被错误地用作剧情内容的替代品；确实，许多游戏失去潜力是因为开发者认为自由玩法可以弥补故事情节的缺失。但甚至对于我们理想化的儿童，玩真正的沙盒也很快就会厌烦。

沙盒隐喻本身已经暗示了沙盒玩法设计的主要问题：玩沙盒的孩子如果想获得真正的乐趣，必须有大量指导。给孩子玩具以后，必须告诉他们怎么玩这个玩具。父母必须提供有意义的指导。简单地把孩子丢在沙盒里，孩子是不会玩得开心的。

沙盒设计也是一样的。如果沙盒游戏没有丰富的可能性，那么就与真正的沙盒没什么区别了。想象一下，一个装满沙子的游戏盒子：想象力丰富的玩家可能会玩上一会儿，但这种玩法确实玩不久。

随着游戏世界的发展，必须有一个指导沙盒元素呈现的框架。这个框架通常表现为奖励系统，比如探索新区域、执行新活动，学习更复杂的玩法、展开更丰富的剧情、解锁更多任务，等等。可以以探索游戏的空间为基础，也可以以观察游戏世界的发展为基础。

框架通常意味着把大量剧情元素分散到游戏世界的各个角落，让玩家去发现。开发者不是把沙盒放在玩家面前就一走了之，而是把游戏元素按某种顺序排列组合，让玩家思考游戏策略，并周期性地奖励玩家的游戏行为。

一个普遍的误解是，沙盒游戏的故事不是由游戏的开发者决定的：相反地，故事应该由玩家决定和引导。但甚至最自由的沙盒游戏的设计师也必须好好研究如何制作一个能让自由玩法确实有趣起来的游戏世界。如果沙盒是有趣的（这绝不是保证），那么游戏的可能性、潜在的乐趣——包括剧情和所有使自由玩法吸引人的东西，都一定是经过开发者精心处理的。

“沙盒”有时候会挑战传统的故事叙述，但它总是增加一些新东西——因此，它并没有移除剧情，而是把预设的剧情转变成动态的、响应性的情节。换句话说，沙盒游戏与一般游戏的区别在于，沙盒游戏使响应更有意义。

这也许也我们对沙盒玩法的印象不符，我们以为沙盒玩法是绝对自由的，但还是那句话，沙子本身是没有什么乐趣的。自动的、复杂的和（也许最重要的）直接的响应性是沙盒玩法必不可少的。游戏世界越复杂、响应越敏感，这个沙盒就越有趣。

沙盒的有趣之处不在于允许完全的自由，而是它概念化和参数化、找到玩家角色的竞技场和巧妙地构建了游戏的潜在空间。它使玩家觉得自己能够自由地玩，自由地探索游戏空间。它让玩家产生控制感，而实际上开发者并没有完全放弃对游戏世界的控制权。

兴起：新类型

随着热门游戏从街机厅进入客厅，游戏也显得更加贴近现实和悠闲。

在街机时代，玩家为了进入下一关（或为了让排队等他玩完的人），必须以尽可能快的速度杀死对手。

然而，现在的游戏不仅可以给玩家休息时间甚至玩家自己也渴望偶尔停下来，好好探索游戏空间，而不是急匆匆地赶到必然的目的地。

许多流行的游戏类型应运而生，如冒险游戏和飞行模拟游戏。

1978年，Robinett为Atari 2600开发了一款叫作《Adventure》的游戏，这个游戏名称取得恰如其分，因为正是因为它，冒险类游戏从此流行开来。1980年又诞生了两款更加复杂精致的冒险游戏《Rogue》和《Ultima》。

1982年，永恒的经典《Pitfall》和《E.T.》问世了。玩家现在可以在基本上开放的世界里闲逛了。《吃豆人》逃出它的迷宫，发现外面是一个等着他去探索的世界。

看似古老的类型，飞行模拟游戏兴起于80年代，以subLOGIC的游戏《Flight Simulator》为代表（又是一款名字取得恰如其分的游戏）。这款游戏后来授权给Microsoft。这款游戏是自由玩法的开创之作—-还有什么比在广阔天空中飞翔来得更自由呢？但这款游戏的根本问题是，天空是空的，所以玩家其实没有什么地方可去，没有什么事可做。除了移动还是移动。

当然，移动本身就是一个很好的游戏概念，这已经被跑酷类游戏（《刺客信条》、《镜之边缘》）所充分证明。移动与体育游戏存在密切的联系。另外，探索是开发世界游戏的基础玩法概念。所以，虽然早期的飞行模拟游戏缺少剧情或活动，但它们也许仍然体现了开放世界的纯粹乐趣。

1983年《Elite》问世了。这款集大成之作转移了沙盒游戏的范式。

《Elite》在许多方面都有突出表现。它的图形引擎是原创的，且具有开创性意义：线框3D图像和隐藏线移除是重要创新。宇宙的自动生成技术非常强大，战斗系统也很高明（尽管subLOGIC/Microsoft的《Flight Simulator》在1982年已经把空战模拟得很好了）。它的经济系统本身就能当成一种游戏。它的玩法也非常丰富。

但《Elite》显得如此有深度，是因为它体现了一个游戏世界的空间、移动和选择的自由。游戏世界不再像封闭的迷宫，而是一个开放的宇宙——所以沙盒游戏的隐喻开始获得新的意义。

1984年，《The Seven Cities of Gold》面市，标志着一类交易/探索/战斗/冒险沙盒游戏的诞生。这类游戏通常以太空或海洋为游戏背景（自由的重要隐喻）。这款游戏的继承者不胜枚举，比如《Starflight》(1986)、《Pirates!》(1987)、《Star Control》(1990)、《Privateer》(1993）和《X (1999)、《Freelancer》(2003)、《Darkstar One》(2006)和《SpaceForce 2》(2007)，等等。

纵观电脑游戏的整个历史，只有两次革命达到相同的高度：一是多人游戏的兴起，二是范式转移：从2D平台转向3D世界——从《Elite》中的座舱视野已经可以预料到这股趋势，尽管在街机游戏《Battlezone》(1980)已经看出来了。

（从技术上说，Jim Bowery的《Spasim》（1974）上第一款多人3D战斗游戏，但因为它是在PLATO网络主机上运行的，它的受众面实在太狭窄了。）

然而，直到16年以后，游戏设计师才开始使用“沙盒”这个术语形容这种自由玩法。尽管如此，开放世界的概念基本上是一样的，从《Elite》一直到 《刺客信条》、《孢子》或《侠盗猎车手5》。

发展：新趋势

这些年来，自由玩法类游戏中又出现了许多趋势，其中最流行的莫过于城市建设游戏。这类游戏自1982年《Utopia》推出后开始流行，但真正蓬勃发展是当它摆脱策略/竞技游戏的影子，成为名副其实的“自由”建造游戏。

这类游戏的魅力来源于设计游戏世界的固有乐趣——这是游戏开发者工作时一直感受到的快乐。一位名叫Will Wright的游戏开发者认为应该把这种乐趣与玩家分享，于是《模拟城市》诞生了。这款游戏是划时代的杰作，是90年代最大一类游戏的代表。

自由玩法有时候也与经济模拟游戏如《大富翁》相结合，《铁路大亨》（1990）是这种游戏的先锋之作。在它之后的十年里，自由玩法又与竞技类游戏等融合，于是有了《SimIsle》和《Capitalism》（1995）之类的游戏。

开放游戏设计在一定程度上，预示了现代玩家生成内容类的游戏的兴起，从《第二人生》到《小小大星球》再到《孢子》。

飞跃：鼓励玩家实验

“沙盒游戏”的概念终于在世纪之交的时候确立。大约就在这个时候，《模拟人生》和《侠盗猎车手3》发布了。人们普遍认为这两款游戏是“沙盒游戏”的始祖和标准。

这个词的发明确实伴随着游戏设计的新发展，但如隐喻所暗示的，这不是玩家自由。玩家自由已经通过许多方式实现了，比如非线性、缺少目标或中心剧情线、游戏世界和游戏行为的自动变化。

正是在响应性和鼓励玩家实验方面，这些游戏体现了游戏设计发生了缓慢但革命性的变化。

“沙盒”是一种新的开发方向，因为它暗示着设计师对玩家的新承诺：自动响应玩家行为。在这个意义上，沙盒并不意味着“自由游戏”、“非线性”等，而是暗示着沙盒本身就是一种玩法风格，自有它的乐趣。

最重要的是，这意味着设计细节上的飞跃性进步。从《侠盗猎车手2》到《侠盗猎车手3》的沙盒品质的进步，确实惊人。从鸟眼到3D的转换打开了世界，并将它从卡通“风火轮”平台游戏变成模似现实的游戏。但关键是，编剧和细节兑现了上述承诺。

正如开头所说的，沙盒设计促进玩家自由感的产生，同时提供了玩法的框架，和丰富而精细的互动世界。《模拟城市》（2000）和《侠盗猎车手3》（2001）就是最典型的例子。现在我们来看看它们的革命性体现在哪里。先说《模拟城市》。

可信的角色：心理游戏、人工生命和AI

《模拟人生》在商业和文化上都获得巨大成功，它代表了这一类游戏的崭新开始——意味着我们也许可以忘记这个类型的源头《Little Computer People》（1985），尽管后者也风靡一时。

在90年代游戏圈进行了几个研究，旨在分析什么样的玩法结构和表现法/界面可以增加玩家对游戏的依恋、什么东西能利用玩家喜欢和渴望以有意义的方式与虚拟角色进行互动。这些研究不知为何总是拘泥于游戏世界的隐喻——把玩家带进虚拟空间并留在那里：使“身体”接触（例如点击鼠标表示抚摸）、共享“空间”（例如玩家和角色可以操作相同的物品）等成为可能。

今天，我们太接近这种虚拟了，以至于越来越难观察到它的机制，但沙盒玩法的基本方面就是形成邻近性的心理幻觉，如果不是持续性的话。

说到具有心理效应的程序，我们会想到AI的双重性。任何一位AI设计师或程序员都会告诉你，设计“可信的NPC”的任务包括学习智能这个复杂的哲学概念的表现和意义：智能的心理意象。

促成这个意象的却是潜层程序——在完全不同的意义上或多或少是“智能的”。我们所谓的程序的“智能”，只是指自主程度和普遍性。本文并不适合深入探讨特定的AI技术，但我敢说，相当简单的程序就可以做出非常可信的NPC AI。

NPC程序员的计划，基本上就是写提示性和可解释的行为，这样玩家就能“读取”更多隐含的信息而不仅是表面上所看到的那些。电脑玩家很擅长国际象棋或格斗之类的游戏，因为这类游戏有比较简单的规则、容易验证的成功条件，等等。

但除此之外，真正的智能程序的问题已经不是我们目前的技能水平能解决的，也许将永远存在。游戏中的NPC的品质的问题总是归结为欺骗问题。

沙盒玩法追求可信的角色主要是因为，角色更富动态，有互动性。它们帮助“推销”游戏世界，因为它们看起来更逼真，甚至足以使你忘记它们的人造属性。NPC的反应越智能，游戏就更像自由而开放的世界。

AI的类型非常多，可能非常复杂，但总体上是目标导向的。程序员构思好目标行为，然后编写能达成这个目标的代码。与AI相比，人造生物是自下而上的程序，与突现性有关。突现行为不一定能提前知道。

《模拟人生》，特别是它借鉴的游戏，都深受90年代的电脑科学的技术开发的影响，特别是人工生命。到2000年，这已经变成一种操纵自动NPC行为的艺术，比如《Majesty》。

在这款经典游戏中，没有玩家角色，如果几乎没有玩家行为。但是，我们有NPC，它们的行为不可以被直接控制，但可能受到间接影响：添加刺激物，然后观察这些“机器人”如何反应。这是一种好玩的模式，我们期望在即将问世的《Majesty》续作中重温经典。

玩自动化的系统，观察NPC AI之间根据程序发生互动活动，或甚至观察人工生命虚拟生物体过它们的日常生活，一直是并且仍然是沙盒玩法的重要亚类。另外，可信和自主的角色已经成为沙盒玩法的核心，因为它们产生丰富的互动空间，极大地帮助树立开放世界的美学标准。但在另一种风格的沙盒游戏中，游戏空间本身就扮演了这个角色……（本文为游戏邦/gamerboom.com编译，拒绝任何不保留版权的转载，如需转载请联系：游戏邦）

The History and Theory of Sandbox Gameplay

by Steve Breslin

It’s such a buzzword nowadays — sandbox. It is a very abstract concept, like “liberty” or “love,” so there are a lot of varieties. Modern sandbox games draw from a wide range of design structures: from open-world design to emergent behavior, from automation of believable agents to multi-threaded or non-linear story.

Being applied in such a broad range of situations means that the word “sandbox” risks its meaning becoming watered-down, confused, and sometimes forgotten.

On the other hand, it remains the single most important design issue for current and future generation games. It’s a great blessing to spend a while in serious thought, on such a critically defining idea.

Let us take this opportunity, then, to reflect upon the different ideas we as gamers and designers have of the notion. Let us think about where the whole idea came from, and consider where we’ve come to, as we look toward the many futures of this wonderful little concept.

Just to get rolling, let’s consider the concept in abstract:

The Ironies of the Metaphor

The concept of sandbox-style gameplay, as we know, suggests more-or-less undirected free-play. The metaphor is a child playing in a sandbox: the child produces a world from sand, the most basic of material. This in contrast to a game where the upper-level content is presented fully formed and ordered.

The metaphor of “sandbox” suggests something pure and free. It implies that it is a young child in the sandbox (and a pre-videogame child at that, with no toys), and assumes an idealized childhood imagination, an unlimited creativity. It is a good metaphor, and a useful one, but the metaphor is also a little misleading, insofar as it suggests a sort of dream-world imaginative capability of the audience, which is not always justified.

The implications of the metaphor are not necessarily carried over by game designers: we anticipate that less imaginative players will get less out of a sandbox game, and this is fine. But even so, the idea of leveraging the player’s imagination is quite ambitious, and more than a little risky.

By itself, this design concept is so ambitious — “give them a sandbox, and they will build castles” — that it must be met with a far greater investment in making the sandbox actually work, which generally means much more money and time invested across all levels of production, and particularly upper-level design and writing. It means an especially close relationship between programming and upper-level design, with the anticipation that the upper-level design will often determine the lower-level specifications.

If normal game design is developing upper-level material (missions, etc.) based on an engine, sandbox design is writing an engine to express upper-level gameplay concepts. Of course, it’s very silly to put it so simply as that: indeed, game production is always a back-and-forth between programming and design.

But basically, sandbox design requires the development of engines which enable open exploration in various ways, engines which support upper-level sandbox design by providing systems for the handling of the sandbox elements. It’s fun work for a systems programmer, but it’s not easy. Then, on the upper level, sandbox requires design which emphasizes and encourages free-play, as well as the development and implementation of a wide range of dynamic interactive elements.

And it’s not just the presentation of the sandbox elements and the play space, but it’s handling all of the player’s various interactions, all the possible combinations. To say it very simply, a typical game must respond to correct input, while a sandbox game must reward all input.

While a physical sandbox is very easy to build (compared with most other toys), the sandbox game generally requires far more work than similar, less open and responsive games. Unlike the person who builds a physical sandbox, a sandbox-style game designer cannot simply offload the creative effort onto the gamer.

The Necessary Framework

Unfortunately, sandbox design is sometimes taken to justify the exact opposite: “sandbox” sometimes serves as an excuse for less investment, particularly in high-level design. Sandbox elements can be mistakenly taken as fair replacements of narrative content; indeed, many games have missed their potential because they imagined that free-play would compensate for a lack of narrative. But even for our idealized child, playing around in a physical sandbox gets old pretty quick.

This principle design problem of sandbox-oriented gameplay is already subtly suggested by the sandbox metaphor itself: a child playing in a sandbox needs a lot of direction if they’re going to have very much fun. They need toys first, and they need to be given ideas of things they can do with them. The parent needs to provide a meaningful framework. Just dropping a kid in a sandbox does not work.

The same is true of sandbox design. If the design effort fails to produce a game rich in intriguing potential, it’s very much like shipping a literal sandbox. — Imagine a game-box literally filled with sand: the open-minded player might enjoy playing in the sand a bit, but the gameplay really isn’t worth a lot.

The necessary framework guides the presentation of the sandbox elements as the world develops and unfolds. This is often expressed as a reward system, which can involve new areas to explore and new stuff to do, more difficult gameplay structures to navigate, more story unfolding, more missions becoming available, and so on. It can be based on exploring the space of the game (exploring Liberty City for example), and it can be based on watching the game-world develop over time.

It often means scattering a great number of narrative elements across the game-world for the player to discover. Rather than presenting the sandbox as “here’s a box of toys, goodbye,” the framework gives some strategic order to the game’s elements, a presentational structure — and thus it gives the player periodic rewards for playing.

A common misconception is that the stories of sandbox games are not determined by the game’s developer: instead, the story is supposedly determined and directed by the player. But even designers of the most free-form sandbox games must specialize in producing worlds which are geared towards making that free-play fun. If the sandbox is interesting (and this is by no means guaranteed!), then the game’s potentialities, the potential interest and fun — including the narrative undercurrent and whatever else makes the free-play engaging and worth the time — are all very carefully handled by the developer.

“Sandbox” sometimes challenges traditional narrative, but it always puts something new in its place. — Thus, it does not remove the narrative, but rather transforms predetermined narrative into dynamic, responsive narrative. In other words, the sandbox game distinguished itself by making the responses more significant and meaningful.

This is perhaps contrary to an image of sandbox play which emphasizes pure freedom, but again, sand by itself is not much fun. Automated, complex, and perhaps most of all, directed responsiveness is essential to sandbox play, and the more complex and responsive the world, the more interesting the sandbox.

What is interesting about the sandbox form is not that it allows full freedom, but that it generalizes and parameterizes, it finds arenas for agency and gently crafts the potential space of the game. It fosters a sense of free-play and exploration of that space. It engenders a sense of player control, without actually handing over the reins entirely.

Prelude: Leisurely Play, Discovering Elite

As popular gaming moved from the arcade into the living room, the stage was set for a less frantic, more leisurely presentation of the action — gaming “off the clock.”

No longer was there a need to kill the player off as quickly as possible, in order that he (or the people waiting in line behind him) insert another quarter.

It became feasible and even desirable to give the player a break from the action, some time to thoughtfully explore his environment, rather than race him towards inevitable destruction.

Thus were born a number of popular gaming genres, including the adventure game and the flight simulator.

The adventure game popularly began in 1978 with Warren Robinett’s breakthrough game for the Atari 2600, entitled, appropriately enough, Adventure. 1980 saw the release of the more sophisticated and seminal Rogue and Ultima.

This genre moved through the popular classic Pitfall and the unforgettable catastrophe E.T. (both, 1982). The player now had his leisure — his world was now basically open. Pac-Man had broken out of his labyrinth — and found a real world waiting for him outside.

Adventure

A seemingly distant genre, the flight-simulator, popularly began in 1980 with subLOGIC’s appropriately-titled Flight Simulator, later licensed to Microsoft. These games were groundbreaking for the sense of freedom — and what better sense of freedom than flying through the open air? Their basic problem was that the air was empty, so there was literally everywhere to go and nothing to do. The game was the movement alone.

Movement alone is a fantastic concept for gaming, of course, as has been well demonstrated by recent parkour-inspired games (Assassin’s Creed, Mirror’s Edge), and the closely-related genre of sports games. Also, exploration is the fundamental gameplay concept of open-world games. So, even while the early flight simulators were devoid of narrative or action, they were perhaps the first pure expression of open-world joy.

Then there came Elite (1983), which synthesized these emerging forces, and in so doing shifted the paradigm.

Elite

Elite was outstanding in many ways. Its graphics engine was original and groundbreaking: wireframe 3D graphics with hidden-line removal was a big deal back then. The auto-generation of the universe was brilliant, and its combat was clever (although dogfighting had already been incorporated by subLOGIC/Microsoft’s Flight Simulator back in 1982). Its economy was a game just by itself, and it had a rich gameplay all around.

But Elite was truly profound because it presented a game-world space and a freedom of movement and choice that for the first time felt real and unbounded. The game-world no longer appeared to be a closed labyrinth or a hilly continuum, but was now an open universe — and so the game-world metaphor began to operate on a new level.

With The Seven Cities of Gold (1984), this was of course the birth of a genre: the trade/exploration/combat/adventure sandbox, typically in space or at sea (key metaphors of freedom). The successors are far too numerous to list, but they include: Starflight (1986), Pirates! (1987), Star Control (1990), Privateer (1993, and following), X (1999, and following), Freelancer (2003), Darkstar One (2006), SpaceForce 2 (2007).

In the whole history of computer games, there have been only two other innovations which are on the same level as this moment: 1) the explosion of multi-player; and 2) the paradigm-shift from 2D “platform” to 3D world — the latter already anticipated by Elite’s cockpit view, though this was already done in the popular arena by the arcade game Battlezone (1980).

(Technically speaking, Jim Bowery’s 1974 game Spasim was the first multiplayer 3D combat, but as it ran on a PLATO network mainframe, its audience was relatively small and specialized.)

However, it would be about sixteen years before game designers began to use the term “sandbox” to describe this kind of free-form play. Nevertheless, the concept of the open game-world is essentially the same, from Elite all the way to Assassin’s Creed, Spore, or GTAIV.

Building

The intervening years saw many trends in free-play, the most popular of which was the city-building game. It began in 1982 with Utopia, but the city-building genre really came into its own when it ceased to be strategic/competitive and became instead an exercise in “free” building for its own sake.

The genre grew out of the natural pleasure of designing game-worlds — a pleasure that game developers experience all the time. One developer, Will Wright, thought that it would be a good idea to share this joy as directly as possible, and this insight led to the development of SimCity, which became a record-breaking success, defining one of the largest genres of the 1990s.

Sometimes this sort of free play was blended with economic simulation, in such as the Tycoon games, starting with Railroad Tycoon (1990). Various more-or-less competition- and objective-oriented games joined its ranks throughout the following decade, from SimIsle to Capitalism (both 1995).

Opening game design to the player, even to a very limited degree, heralded modern player-generated-content games, from Second Life to LittleBigPlanet to Spore.

Encouraging Player Experimentation

The metaphor of the “sandbox game” finally emerged at the turn of the century, around the publication The Sims and the following year, Grand Theft Auto III, the two games which are traditionally considered the two original and canonical “sandbox” games.

The invention of the term did indeed accompany a new development in game design, but this was not, as the term suggests, player freedom, which was already available by any number of means: non-linearity; the lack of objectives or central storyline; automatic variation of the game-world and game-behavior.

It was in terms of responsiveness and encouraging player experimentation that these games represented a gradual but transformative change in game design.

“Sandbox” was a new development because it indicated a new promise: automated responsiveness to player behavior. In this sense it does not mean “free play,” “non-linear,” and the rest; rather, it indicates that which makes this style of play specifically and particularly interesting in its own right.

Most of all, this meant a radical development in design detail. The evolution of sandbox-oriented quality between GTA2 and GTAIII is truly astounding. The switch from bird’s eye to 3D opened the world and shifted it from cartoonish “Hot Wheels” platformer to a realistic city. But the critical part was that the writing and detail followed through on the promise.

As mentioned at the beginning, sandbox design facilitates and encourages a sense of player freedom, while providing a framework for play and a rich and detailed world for interaction. This was definitively achieved by The Sims in 2000, and in 2001, Grand Theft Auto III. Let’s now consider their innovations, starting with The Sims.

Towards Believable Characters: Psychological Games, A-Life, and AI

The amazing commercial and cultural success of The Sims might suggest that it was entirely new — which means we are likely to forget that the genre began with Little Computer People (1985), even though the latter “game” was well celebrated in its time.

This is the birth of the mind game, the virtual seduction.

There were several studies in the 1990s, of what gameplay structures and presentation/interface regimes increase attachment, what exploits the player’s tendency and desire to interact in a seemingly meaningful way with the artificial character. These always somehow literalize the metaphor of the game-world, bring the player into the virtual space and enmesh him there: enabling “physical” contact (mouse-petting), sharing “space” (e.g., the player and the character can manipulate the same on-screen objects), and so on.

Today we are so close to such virtuality that it has perhaps become difficult to observe its mechanism, but a primary aspect of sandbox play is the formation of a psychological illusion of contiguity, if not continuity.

Thinking more towards psychologically effective programming, let us consider the dual nature of AI. As any AI designer or programmer will tell you, the task of designing a “believable NPC” involves fostering an appearance or impression of that elusive philosophical notion of intelligence: the psychological impression of intelligence.

What contributes to this impression, however — the underlying program — is more or less “intelligent” in an entirely different sense. Where we speak of the “intelligence” of the program, we mean only the level of autonomy and generality. This is not the place to get into the specific maneuvers and techniques, but be assured that relatively simple programming can lead to really convincing NPC AI, and really it’s mostly in the presentation.

The NPC programmer’s plan, then, is essentially to write suggestive and interpretable behavior, so that the player will “read in” a lot more sophistication than is actually present. Computer-players can be good at winning a chess match or a combat, which has relatively simple rules, easily-validated success cases, etc.

But beyond this, the question of truly intelligent programming (in that ephemeral, philosophical and psychological sense) is well beyond our technological horizon and may well remain there forever. The question of NPC personality in games is always the question of faking it.

The main reason that this trend towards believable characters is compelling for sandbox play is that the characters are, at bottom, more dynamic and interactable. They help “sell” the game world because they seem more realistic. Not “realistic” in the sense that they can ever hope to pass the Turing test, but realistic enough that they’ll lull you into forgetting about their artificiality. The more intelligently the NPCs respond, the more the game feels like a free and open world.

AI is widely various and can be complicated, but in general it is effect-oriented. The programmer has in mind a goal behavior, and writes code to meet this objective. In comparison with AI, Artificial Life is bottom-up programming, and it’s all about emergence. The emergent behavior is not necessarily even known in advance.

The Sims, and especially the range of games it inspired, was heavily influenced by technological developments in computer science during the 1990s, and in particular Alife. By 2000, this has developed into the art of manipulating automated NPC behavior, even in an otherwise traditional title, as we have for example in Majesty.

In this classic, there is no player-character, and little if any direct action by the player. Instead we have NPC agents whose behavior cannot be directly controlled, but only indirectly influenced in some way: add stimuli and enjoy watching how the automatons respond. It’s a delightful gameplay model, which we look forward to revisiting in the forthcoming Majesty sequel.

Playing with automated systems, watching NPC AI agents interact with each other according to their program, or even watching Alife virtual organisms go about their daily life, has long been and remains a key sub-genre of sandbox play. Further, believable and self-motivated characters have become key to sandbox play, because they produce a rich space for interactivity and greatly help establish the open-world aesthetic. But in another style of sandbox games, the game space itself plays this role….(source:gamasutra)