作者：Pascal Luban

电子游戏运用物理元素的情况并不鲜见。相信许多人都记得《Lunar Lander》和《Marble Madness》这类完全融入重力效果的游戏。而今天面向大众市场的新颖游戏，一般会运用新技术解决方案来强化游戏中的物理效果。

采用物理控制方式要求游戏运行设备具有较高的运算能力。多核CPU以及专业物理卡（例如Ageia公司开发的产品）销量的增长，为当今游戏增加物理效果创造了理想的条件。

但现在的问题就是，我们应该如何使用这些新资源。目前为止，多数动作游戏中的物理元素仅局限于装饰性的特效，这些特效虽然有助于增加玩家的沉浸感，但却无法真正改变游戏玩法。

我们需要探索物理元素在游戏玩法中的运用方法，以及如何通过这种元素为玩家带来全新游戏体验。

本文宗旨是分享我在设计CTF-Tornado多人地图（游戏邦注：这是《Unreal Tournament 3》mod中的一个地图，采用了Ageia开发的处理器，该地图由Gameco Graphics工作室开发）时的经验和心得。

定义

首先我们要厘清一些物理效果的定义。物理元素并不仅限于重力模拟和物理碰撞的情形，它还包括以下应用方式：

·流体动态（包括液体和气体）

·软体、硬物的变形（例如纤维、金属等）

·模拟摩擦和粘度状态

·物体变质过程（例如水从液态凝结成固状）

·物质破裂

这些物理效果涵盖范围极广，有些效果至今未运用于游戏领域。可见物理效果的应用仍有巨大的发展空间，但开发者都要面临同样的挑战。

应用物理效果的挑战

·要求运行设备具有较高计算性能；

·运用于多人游戏的难度极大；

·难以兼容特定游戏的规格及其他物理效果。

对计算性能的要求

尽管Havok等优秀的物理引擎已经问世好几年，但物理控制方式要求设备具有庞大的计算性能，这导致多数游戏对此望而却步。

当前仅有一小部分游戏会为物理效果分配一定的CPU功率，每个核心一般只会预留10%-25%。但物理效果仍然需要消耗大量资源，以下我们仅以最简单的碰撞效果为例：

每个动态物体的移动都要受到许多参数（游戏邦注：例如移动方向，速度，沿多条轴线旋转等）的影响，而每个画面都需要重新计算参数。也就是说，动态物体间的互动也需要计算参数。10个动态物体彼此互撞所需的运算量，远甚于静态物体。这里有两个解决方案：

·采用具有庞大功率的多核CPU。双核CPU运算能力仍然很微弱，四核CPU或许可支持大量的物理应用。因为四核虽然具有更强大的运算能力，但游戏引擎的要求条件也会随之上升，所以我们还不能确定四核CPU是否还能为物理应用预留一些功率。另外，多核的程序设计更为复杂，而且会产生更多开销。也许八核处理器才是解决对策。

·第二个解决方案就是使用Ageia等公司制造的专业物理卡。与其他新硬件一样，如果出现一定数量的成功应用案例，这种物理卡在游戏中的应用也会更为普遍，而这项技术也会因为安装基础的扩大而获得发展。

物理效果需消耗更多的CPU功率

·在一个关卡中使用物理效果会增加AI寻径的复杂度。这些物理效果还需要根据周围的环境变化作出调整。如果有个巨大的障碍物从天而降卡在半路中间，设计游戏AI时就得考虑到这个因素，以便由AI控制的NPC可绕着该物体走，或者把它当作掩护体。

·光影效果必须具有动态。假如物体移动或者墙壁被摧毁，这时候就无法预先计算光影的参数。因此就很有必要使用动态的光影效果。可以选择低对比度的环境来避免这种情况，但这会影响地图的画面质量。

多人游戏中的挑战

从游戏玩法角度来看，多人游戏采用物理效果是一个很有趣的设置，因为它可以让玩家根据自己的优势调整游戏布局。但与单人渡相比，多人游戏更具局限性，例如网络带宽和缓冲时间等问题。这其中的难度就在于让那些会直接影响游戏玩法的事件，在所有参与游戏的设备中同步。

目前来看，多数游戏仅需同步玩家的位置及其发射的导弹。但假如物理效果与游戏玩法直接相关，那么所有的物理事件（游戏邦注：比如实体对象、微粒云等很可能阻挡视野、破坏区域的内容）都要进行同步。

不幸的是，这种局限性与游戏设备的计算性能无关，不过我们还是有一些方法可支持多人游戏植入物理效果。可采用的策略就是选择锁定客户设备，并且仅需少量同步的物理效果。这样就可以限制对玩法有影响的大型物体数量（因为这些物体需要在所有设备上同步）。

另外，由微粒组成的云或者小型物体并不需要实现在所有设备上的完美同步效果。只要同步云的位置及其造成的破坏量即可。假如需要同步一座了望塔倒塌的效果，那就只要在所有设备上同步该塔的破坏量及碎片下落的情况，而无需同步碎片本身的细节，否则就会面临一项庞大的工作。只要局部处理碎片之间的碰撞效果即可。

关卡设计在动工之初就要将这些局限性考虑入内，设定好可同步化的物体，最大化可局部处理的物理效果数量。

以物理效果制造意外玩法

出于游戏开发成本等原因，多数单人游戏通常采用线性关卡设计，以便玩家充分体验游戏预设的特效，过场动画、战斗脚本等内容。线性关卡设计还有助于控制游戏节奏。如果玩家在某处漫游久了，却并未发现有趣之物，可能就会感到厌倦。

当然也有一些游戏提供的是开放环境，例如多数RPG或特定的户外动作游戏（如《孤岛惊魂》）。不过从总体上看，大多数动作/冒险游戏采用的是线性或半线性框架。

在这种情境中使用物理元素可能会产生一些关卡设计师未曾预料到的情况。这就是所谓的意外玩法。

这类玩法通常很受欢迎，但在这里使用物理元素可能就需要更改关卡的布局，因此会造成一些类似于玩家行动受阻、角色AI受到干扰，或者关键道具消失等情况。这类问题在多人游戏地图中也时有发生。

我们在设计CTF-Tornado时很快就意识到大型物体因龙卷风而产生的移动，或者玩家行动可能会阻挡前往基地的通道，从而导致他们无法返回等后果。我们必须为玩家提供这种选择，因为它可以带来新的策略性玩法，但得避免玩家在地图上体验游戏受阻的情况。

结果，我们创造了多种解决方案：增加了通道的数量，让玩家使用Impact Hammer这种具有击退效果的武器自己清除障碍。

在游戏玩法中的应用

除了以物理元素作为主要玩法机制的游戏之外，多数游戏仅将这一元素作为装饰性效果。即使是今天，仍然鲜有游戏使用物理元素来优化玩法。原因很简单，动作游戏等大众市场产品已经极为消耗运算能力，而物理效果尤其占用这种资源，并且会极大影响实时播放效果等其他参数。

但今天，无论是哪种游戏都可以考虑使用更多物理元素，原因何在？

在我看来，这一元素在游戏玩法中有四种应用方式：

*为玩家创造克服挑战的新方法

*创造移动的游戏环境

*发展强大的学习机制

*支持玩家自己创建工具

为玩家提供新工具

多数游戏的玩法主要有两个核心理念：1）让玩家克服挑战，例如打败一帮敌人；2）为玩家提供致胜工具，例如武器、动画效果、背景元素等。游戏玩家的目标是掌握工具的使用方法，并巧妙地用它来克服挑战。

从这个角度看，游戏向玩家提供的任何一种新“工具”都应该有助于他们实现目标。物理元素也不例外，假如它不能为玩家带来克服困难的新方法，那么它对游戏玩法来说也就毫无意义了。

因此，我们设计游戏时就要考虑到这一点，因为使用物理效果极为消耗资源，它相当于项目动工之初的重大决策。现在我们将介绍数种利用物理元素改善游戏玩法的对策。

以动作游戏为例，这类游戏的玩法多取决于战斗和移动的挑战性。物理元素应为这类游戏玩家提供应对以下问题的新工具：

*弱化或消失敌人

*让玩家实现自保

*打开或关闭通道

*探测敌人

*躲避敌人

了解玩家的意图之后，我们就很容易想到一些实际的解决方案：

*摧毁背景元素有利于玩家从更有利的位置接近敌人，建立一道自我保护的屏障，打开新通道或者关闭原有的路径。

*物体的流动性也可以在这里派上用场。流动性的物体可能是液态或者气态。我们可以让玩家点燃火把，让风将其吹向合适的方向，让玩家的动作所产生的烟雾屏蔽敌人的视野，从而获得新的制敌策略。移动或者延伸的液体可能极大影响其他物体的物理状态，例如导致有些物体下沉，有些物体则浮出表面。堆积物体，或者清空场所也可能明显改变战斗和移动环境，从而在一个已被发掘的区域产生全新的游戏玩法。移动的物体也可能带有一种气味，从而方便玩家探测敌人的行踪。

非静态游戏环境

当前几乎所有游戏的关卡都是静态的，只有敌人出现才能“激活”这些关卡。这里我们可以将游戏环境本身想象成一个敌手，或者说它至少能够提供一些富有变化的条件。物理效果在变化的环境中可以表现为物体下坠、失衡、物体因地面坡度而无法移动等状态。

假设有一款动作游戏的背景环境是一艘下沉的轮船。船舱都积满了水，堵塞了一些通道，改变了角色的行动方向。船体的角度也会发生变化，大型物体会沿着甲板下滑，它们可能成为障碍，也可能成为玩家的武器。最大的变化是船体的角度，它可能已经调头或者呈垂直状态，从而使船体上的物体流动性发生巨变。

类似的情形还包括：火灾、地震、海啸、爆炸、海洋风暴、重力变化或太空增压状态等。

我们开发CTF-Tornado的情形与此类似。我们将龙卷风作为“第三支军队”，使其成为交战一方中的优势或劣势。龙卷风堵塞或打开了地图中的无数通道，导致玩家无法走捷径，它还通过摧毁墙壁或掀翻屋顶而改变地图上的防御条件，甚至可以左右玩家的导弹射程。

为玩家提供强大的学习机制

玩游戏是一种探索和学习机制，例如，FPS玩家可以在游戏过程中边玩边学，他们会先预期对手的反应，然后再据此判断自己应该使用多大的火力。

他们如何做到这一点？答案就是探索和测验游戏环境（游戏邦注：例如使用武器和评估结果等方式）。这样玩家就会在游戏中学到如何使用自己之前不了解的工具。但如果游戏中的因果效应不是那么明显时，这种机制的效用就会打大折扣（游戏邦注：有些益智游戏系统只能响应设计师的逻辑，而非玩家的操作行为，由此我们就能看到因果效应的重要性）。

物理元素尤其适合植入此类自学机制，因为我们了解现实世界的物理现象（例如，我们本能地知道重力和流体物理学将如何影响溢出的液体）。为玩家提供基于物理元素的游戏玩法，有助于他们找到适合自己的解决方案。

例如，在《半条命2》中的一些物体就运用到了浮力现象。玩家可以使用具有浮力的木桶让重物飘浮水面，或者使用大量金属块让飘浮的物体沉没。

在《幽灵行动尖峰战士2》（由瑞典工作室Grin开发）PC版本中，玩家可以通过放倒一座塔楼，让敌人全军覆没。在《Switchball》这款益智游戏中，玩家可使用不同密度的球解开一些谜题，有些玩家很快就会发现球体太轻，就不会有足够的能量冲破一些障碍。

物理游戏环境还可让玩家充分发挥自己的主观能动性，以自己的现实生活经验找到解决方案。

我们还可以想象一下关卡设计师可在物理游戏环境中实现的功能。假如玩家被躲在路障之后的敌人围困，他们会想出什么通关妙计？

他们也许可以放倒一棵树或者建筑消灭敌人，或者使用一个大型圆柱体作为移动掩体，让一辆车在斜坡下滑以冲击敌人，或者引爆汽车趁着烟雾弥漫巧妙脱身。这些解决方案均来自我们对环境的观察和对现实世界的理解。

让玩家自己制造工具

盘子、软管或横梁的变形也是一种物理现象。我们可以用这种方法让玩家打造自己所需的工具。扭曲金属板可让玩家制造水道或球轨。一块精心裁切的帆布也可作为求生模拟游戏中的屋顶或者掩体。树枝等脆弱材料可以作为掩盖于陷阱之上的遮避物，而钢片等韧性材料的则可制作原始弹弓。

这些物理现象的应用也许只适用于益智或求生等特定类型的游戏，实际上，游戏趣味性还有极大发展空间。如果建设类游戏也可以采用此类元素，让其中的每一块砖都呈现其物理特征，那么玩家就可以建设一个完全不同的游戏世界。

结语

物理元素需占用大量资源，我在本文提到的一些观点目前暂时无法实现，但相信工具和技术的发展总有一天会让这些设想成为可能。从现在开始，我们就可以通过有效应用物理效果使其优化游戏玩法，而不仅仅是成为一种装饰性元素。让玩家改变游戏动态环境，已经成为当前关卡设计的一个发展趋势。物理效果或许还将继续推进这一变革。

游戏邦注：原文发表于2007年12月4日，所涉事件及数据以当时为准。（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）

Physics in Games: A New Gameplay Frontier

by Pascal Luban

The use of physics in video games is not something new. Many of us lovingly remember Lunar Lander and Marble Madness. The gameplay in such games fully consisted in interacting with gravity. Today it’s new technical solutions that enable an advanced management of physics in mass-market games that is the novelty.

Physics management is quite demanding in terms of computing power. Thanks to the increased sales of multicore CPUs and the availability of dedicated physics cards (such as that developed by Ageia), a much more intense use of physics in games may now be considered.

The real question in such cases is what we are to do with this new resource. Until now, the use of physics in action games was most often limited to cosmetic effects. These are important for the gamer’s immersion in the world but don’t really change the gameplay.

The question is now to know what the possible applications in terms of gameplay are. How are we going to provide the gamer with new experiences?

The purpose of this article is to offer some answers and share my experience which I gained while designing the CTF-Tornado multiplayer map, one of the maps available in an Unreal Tournament 3 mod designed to take advantage of the processor developed by Ageia. The map was developed by the talented Gameco Graphics studio.

Part One: Introduction
Definitions

Let’s start with a few definitions. The scope of physics is not limited to gravity simulation and collisions between objects. Physics also includes the following applications:

*

Fluid dynamics, either liquid or gaseous
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Distortion of soft objects such as fabric or of hard objects such as metal plate or even solid hollow objects
*

Simulation of friction and viscosities
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Changes in the state of matter such as the passage of water from the liquid state to the solid state
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Breaking of materials

Thus physics covers a wide scope of issues, some of which have never been used in games. The potential is huge but the issues faced by the developers are equally challenging.
Challenges arising from the use of physics in games

There are several challenges:

*

The requirements in terms of computing capacity
*

The challenge in multiplayer games
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The incompatibility between the scripted dimension of certain games and the chaotic nature of physics

Let’s take a closer look at each of them.
The requirements in terms of computing capacity

Physics management requires a huge computing capacity. It is not by accident that physics has not been widely used in games so far, despite the fact that good software physics engines like Havok have been available for several years.

In the current games, only a very small portion of the CPU power is allotted to physics, between 10 and 25% of a single core. Yet, physics requires considerable resources. Let’s consider the simplest case, that of collision management.

The movement of each dynamic object is managed by many parameters (direction of movement, speed, rotation on multiple axes) which must be recalculated for each image. Then, interactions among dynamic objects must be calculated. Ten dynamic objects that are packed against each other require far more calculations than if they did not touch each other. Two technical solutions are available:

*

The arrival of multi-core CPUs will provide a massive amount of CPU power. Dual-cores are still too weak but quad-cores will begin to bring the power needed for massive applications of physics. Will it be enough? We don’t know for sure. Quad-cores will provide much more power than we currently have, but game engine requirements will increase accordingly and there is no guarantee that there will be enough extra power left for physics applications. Furthermore, programming multiple cores is more complex and generates its own overhead. We might have to wait for eight–core processors.
*

The second solution is the use of dedicated physics cards such as the one manufactured by Ageia. Like any new hardware, it will pick up when enough exciting applications will be available, which in turn will be developed if the installed base is large enough.

Physics also makes more work for the CPU outside of the physics in itself

*

The use of physics in one level makes the pathfinding far more complex. In fact, it must adapt on-the-fly to a changing environment. If a large block falls down in the middle of a road, the artificial intelligence of the game must take it into account, so that the NPCs controlled by the AI move around the object or use it for cover.
*

The lights and the shadows must be dynamic. If objects move or walls are destroyed, pre-calculated shadows or lights cannot be used. Thus, the use of dynamic lighting becomes essential. This can be avoided by choosing environments with little contrast, but the graphical quality of the map suffers.

The challenge posed in multiplayer gaming

The use of physics in a multiplayer game offers very interesting perspectives from the gameplay point of view, as the gamer can then modify the topology to his or her advantage. However, when compared to a single player game, the multiplayer game offers additional constraints as well: the available bandwidth for sessions played on the internet, and the latency. The challenge is to synchronize the events that have a direct impact of the gameplay on all machines.

Until now, in most games, only the position of the gamers and their projectiles had to be synchronized. If physics is to have an impact on gameplay, all physics events should be synchronized as well: physical objects, clouds of particles that are likely to block the view, damage zones etc.

Unfortunately, this constraint is largely independent of the computing power of the game machine, but several solutions enable the use of physics in a multiplayer session. The strategy to follow is to have a physics implementation whose impact is focused on the client machines and which requires little synchronization. Thus, the number of large objects that have an impact on the gameplay should be limited, as they have to be synchronized on all machines.

On the other hand, a cloud made up of particles or small objects does not require perfect synchronization on all machines. Synchronizing the position of the cloud and its possible damage volume would suffice. Thus, if synchronizing the effects of the fall of a watchtower is desired, what should be synchronized on all machines is the damage volume associated with the fall of debris and not the debris itself, of which there is far too much. Physics locally manages the collisions between debris.

The level design should take this constraint into account from the very beginning by allowing that a maximum number of physical effects should be managed locally, and by providing a “budget” of objects to synchronize.
The incompatibility between the scripted dimension of certain games and the chaotic nature of physics

All games that offer a single experience aim to provide the gamer with the best sensations. For game development cost reasons, such games offer a linear level design, thus ensuring that the gamer takes advantage of the projected special effects, cutscenes and scripted combat situations. The linear level design also allows controlling the rhythm of the game. If the gamer starts to roam in a place where nothing interesting happens, they might get bored.

Of course there are many exceptions that offer open game environments such as most of the RPGs or certain action games that take place outdoors, such as Far Cry, but the majority of action/adventure games provide linear or semi-linear architecture.

In such a context, the use of physics may lead to situations that are unpredicted by the level designer. This is called emergent gameplay.

This type of gameplay is usually welcome, but the use of physics provides for the possibility to change the topology of a level and therefore create situations like blocked movements, disturbance of the characters’ AI or disappearance of key items for the script. These kinds of problems may also occur in the multiplayer maps.

Thus, in CTF-Tornado we quickly became aware that the movement of large objects by the tornado or gamers could block the access to the bases and therefore prevent them from getting back or laying down the captured flags. This option had to be offered, as it opens new tactical possibilities, but care had to be taken not to block play on the map.

Consequently, various solutions were developed: the number of access paths was increased and we offered gamers the opportunity to get rid of the possible obstacles themselves by using the Impact Hammer, one of the Unreal Tournament 3 weapons that provide a repelling effect.

Part Two: Gameplay Applications of Physics

Except for games where physics provide the main gameplay mechanism, physics has been essentially used in games for cosmetic purposes. Even today very few games use physics to improve their gameplay. The reason for this is simple. Mass-market games like action games are already very demanding in terms of computing power and we have seen that physics is especially demanding in that area, and strongly impacts other parameters such as real-time display.

Today, a more intensive use of physics is conceivable, regardless of the kind of game — but for what purpose?

In my opinion, there are four groups of application:

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To give the player new ways to handle the challenges he or she will face in the game
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To create mobile game environments
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To develop powerful learning mechanisms
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To allow the player to build his own tools

Providing the gamer with new tools

For most games, the idea behind the gameplay is: 1) offer the gamer a challenge to overcome, such as defeating a group of enemies and 2) provide him or her with tools to succeed: weapons, animations, background elements etc. The gamer’s objective is to learn how to master such tools and use them wisely to overcome the challenge.

From this perspective, any new “tool” that is offered to the gamer should enable him or her to achieve this objective. The same is true for physics. If it does not provide new ways for the gamer to overcome the challenge, it is completely useless from the gameplay perspective.

This tough reality should always be taken into account, for the use of physics remains highly demanding in terms of resources and implies significant decisions at the beginning of the project. Let’s now look at a few ways to really take advantage of physics to improve gameplay.

Action games represent a major genre, so let’s look at the possible uses of physics in action gameplay. In this kind of game, the gameplay lies essentially on the challenges of combat and movement. Physics should therefore provide the gamer with new tools to respond to the following problems:

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Weaken or eliminate opponents
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Protect himself or herself
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Open or close a passage
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Detect opponents
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Hide from opponents

When the gamer’s purpose is understood, numerous practical applications come to mind:

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The destruction of background elements enables the gamer to reach an opponent from an advantageous point, gain protection by building a cover, open new paths or on the contrary, close existing paths.
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Fluid management offers a totally new scope. Fluids may be either liquid or gaseous. They allow the player to light up a fire or let the wind blow it in right direction. The smoke generated by the player’s actions may impair his opponents’ vision, thus offering new tactical opportunities. A moving or expanding liquid may drastically affects the physics of the other bodies: certain bodies will sink, while other will float to the surface. Filling up or, on the contrary, emptying an area may also drastically change the combat and movement conditions and provide a totally new gameplay in an area previously already exploited. A moving fluid may also serve to carry an odor, thus widening the means of detection available for the gamer… and his or her opponents.

Non-static game environments

Today, almost all game levels are totally static. It is the opponents that animate them. Let’s imagine games where the game environment itself is the opponent, or at least provides changing conditions. Physics allows for changing environments, with all the consequences: falling objects, loss of balance, objects more or less difficult to move according to the slope, etc.

Imagine an action game that takes place on a sinking ship. Compartments fill with water and change the movement of characters by blocking certain passageways, but also by putting out fires. The angle of the hull itself changes. Large objects can slide along the decks and be used as obstacles or even weapons. The complete change of the ship’s angle, such as a turn around or passage to vertical, could lead to a drastic change of the circulation in the hull.

Other situations are imaginable: Fire, earthquake, tidal wave, bombing, sea storm, changes in gravity or space pressurization etc.

It is in fact what we did with CTF-Tornado. The tornado behaves as the “third team”, by helping or putting at a disadvantage one of the two sides. The tornado changes the circulation in the map by blocking or opening numerous passageways. Its simple presence prevents the gamers from taking the shortest passageways. It also changes the defense conditions of the map by tearing off pieces of walls or roofs. It can even sidetrack gamers’ projectiles!

Providing the gamer with a powerful learning mechanism

Playing is not an activity reserved to mankind. It is a mechanism of discovery and learning that had been developed by nature well before Homo Sapiens descended from their trees. Playing is learning. Of course this mechanism applies to our own games. The gamers learn in a FPS to anticipate their opponents’ reactions and to evaluate the power of a weapon, for instance.

How do they do it? By exploring their game environment and by testing it, for example by using the available weapons and evaluating the results. It is thus possible to teach the gamers how to use tools they do not know. But this mechanism becomes much less efficient when the cause-effect relationship is not obvious. You’ve seen this in certain puzzles that do not respond to our logic but rather to that of the game designer that created them.

Physics is especially suitable for this kind of self-learning mechanism, since we know how it works in the real world. Thus, we instinctively know how the forces of gravity and fluid physics will influence a spilled liquid. Providing the gamers with gameplay that relies on physics enables them to find their own solutions to complex problems.

Think this is just hazy theory? Let’s look at a few applications. In Half-Life 2 several moving puzzles lie on a well-known mechanism: buoyancy — or its absence — of certain objects. The gamer thus uses the positive buoyancy of barrels to make a heavy object float or, on the contrary, takes advantage of the mass of the metal pieces to make a floating object sink.

In the PC version of GRAW 2 developed by the Swedish studio Grin, gamers can get rid of opponents entrenched in a tower by causing its fall. Finally, let’s consider the example of Switchball. In this puzzle game, some of the puzzles are solved by using balls of different densities. A player quickly discovers that too light a ball does not have enough energy to make its way through some obstacles.

A physical game environment would allow the player to use his or her initiative and spirit. The player can find solutions by using his or her own real-life experience.

Let’s project ourselves ahead into the future and figure out what a level designer with a physical game environment available could accomplish. Imagine that a gamer is blocked by a group of opponents solidly entrenched behind a barricade. What solutions could he or she come up with to pass?

The falling of a tree or a building could crush opponents, a large cylindrical object could be moved by the player who would then be able to push it to make a mobile rampart, a vehicle could be freed along a slope in order to be used as a ram, a vehicle could explode so that the smoke column mask the player’s movements. All these solutions derive from the simple observation of the environment and from our innate understanding of what is possible in the real world.

Letting players build their own tools

Physics enables the distortion of objects such as plates, hoses or beams. It is therefore imaginable to allow the gamer to shape them according to his or her needs. Thus, by distorting metal sheets, a player can build watercourses or ball paths. A skillfully cut canvas could act as roofing or veil within a survival simulation. The frailness of certain materials such as branches enables the building of traps by covering a hole with the respective materials. The flexibility features of a steel blade or board enable the building of a primitive catapult.

Such applications of physics would probably be limited to certain kinds of games such as puzzles or survival games. In fact, the interface would have to be adapted. But the fun potential of the game could be huge. Imagine a building game where each brick is designed with physical features. The gamer could build a totally unique game environment.
Conclusion

Physics is extremely demanding in terms of resources and some of the ideas that I have developed here are not currently achievable — but the advances in the tools and technologies are foreseeable, giving us the power in the future. From now on, gameplay can be improved with uses that are not just cosmetic. The development of dynamic game environments that the player can change on the fly is already a trend in today’s level design. Physics makes this evolution possible.

Near future technologies will astonish us and provide us with the power increase. The ball will then be in the court of the game and level designers who will then have to take this advantage we need to bring new experiences to the gamer. （source:gamasutra）