浅析即时策略RTS游戏中的动态地图元素

原作者：Brandon Casteel 译者：Willow Wu

在即时战略游戏（RTS）中，我总是很高兴看到游戏的地图能够随着时间而演变（或者至少是其中一部分），通过这种方式对玩家行动做出反馈。其次，我也很喜欢那些不需要玩家输入就能随时间变化的地图，迫使玩家适应不断变化的环境和威胁状况——但我觉得这在竞技游戏中并不多见。

在很多RTS游戏中，尤其是很多经典系列，它们的地图都是静态的。随着时间的推移，玩家的资源变少了（如树木），这就出现了新的行动选项，把目光转移到敌方的资源上。但在这些游戏的对抗中，大多数时候这都被视为次要的战术考虑因素。

不过，在一些战术和策略游戏中，玩家是可以通过各种各样的方式修改地图的：开辟新的攻击路径或封锁它们，改变大家在意和想要争夺的区域，或者让特定区域内的玩家选项变得不可行。

我最早见过的，拥有我称之为“动态地图”的游戏就是Z，一款由Bitmap Brothers开发的老式机器人主题战术游戏。在游戏中，会有悬崖阻挡单位的行进。步兵可以通过投掷手榴弹来摧毁悬崖，当然这会耗尽那些数量有限的资源。坦克也可以直接开火摧毁悬崖。可破坏的悬崖的存在也许对游戏的设计没有太大的影响，但对我小时候的想象力肯定有不小的影响。

举一些更靠近这个时代的例子：Relic的RTS游戏，同样也是带有动态地图元素。在《战锤40K：战争黎明2》和《英雄连2》中，有些高级的单位可以碾碎脚/轮胎下的地形和掩体。一些武器的伤害效果很强悍，可以制造出坑洞，直接成为掩体。此外，当车辆报废时，它们会留在地图上，可以作为掩护或被完全摧毁。随着时间的推移，地图会演变成另外一种形态，到处都是弹坑、冒烟的坦克和半履带车的残骸。

《英雄连2》的地图有天气效果，每隔一段时间就会出现暴风雪，水面结冰、大雪堆积，步兵速度减慢，形成一种恶劣环境，步兵要是接触不到热源就会死亡。有些武器，比如喷火器就可以融化雪堆。这在很大程度上并不是由玩家行为驱动的，但从应对暴风雪这件事来看，这种地图确实迫使玩家做出了有趣的反应。然而，这显然不是一个广受欢迎的系统，因为在多人游戏模式下，这个系统后来就被移除了。

此外，在《英雄连2》中，炸药和某些武器能够通过摧毁部队和坦克下的冰面立刻置他们于死地，让他们沉入到冰冷的水下。除了影响单位在冰面上的行为（避开冰面上的洞），这偶尔也会在冬季的地图上引发一些戏剧性效果。在暴风雪中，冰也会重新冻起来，在冰被破坏和重新结冰的过程中又会出现一连串的不确定性事件。

而《最高指挥官》在这方面就有点不同了：单位死亡/报废后，他们会留下残骸，可以作为资源回收。这片区域就成为了新的目标战场，大家都会冲着宝贵的资源而来。这不会改变地图本身，但会改变玩家与地图的交互方式以及区域价值。

《英雄连》系列游戏，还有刚发行不久的《钢铁收割》，它们都有个相似的概念就是单位死亡后会掉落需要多人操作的大型武器或者可以个人携带的小型武器，之后无论是谁捡起来都可以使用。这在战术方面就多了一定的灵活性（鉴于玩家在游戏过程中会不断获得新的兵种），资源也可以从一个玩家那边转移到另一个玩家。武器都是需要耗费资源制作的，而玩家可以通过这种方式免费获得对手的现成工具。实际上，《命令与征服3》也是这样的，工程师可以重新组装机械掉落的残骸，快速成为一个新单位。

StarCraft 2 Legacy of the Void(from polygon)

《英雄连2》在这一方面的设计是相当优秀的，比任何我能想到的游戏都好（包括《命令与征服3》），任何玩家都可以占据被遗弃的坦克。坦克是非常昂贵、强大的，能够从对手那边夺到一个就算很大的收获了。

我认为这些掉落的武器、坦克等就是“动态地图元素”，就跟我看待《最高指挥官》中死亡单位一样：它们都是玩家对战后的产物，是会出现在地图上某一区域出现的免费资源，任何玩家/团队都能从中受益。而且这时候玩家们会比较重视这些区域的战术/策略（暂时性的）。

其实我真的很喜欢《最高指挥官》的设计方式， 并在我的个人游戏项目中也做了一个类似的系统：SCRAP mod。在SCRAP中，当单位死亡后，它会先燃烧三分钟，才会解体成资源，在真正可以收集之前给玩家时间去思考怎么夺得这些资源。

甚至《星际争霸2》和《灰蛊》也在地图上做了一些尝试，让地图能够随着时间而变化：《灰蛊》中增加岩石，可以阻挡某些通道。而在《星际争霸2》中，摧毁石柱可以堵住通道，再摧毁碎石就能重新打开通道了。

我们再来讲讲地形的问题。

一般来说，动态地图元素的应用重点在于单位在地图上行动模式。可破坏的桥梁就是一个很好的例子——在几个《命令与征服》游戏中，工程师们从桥的任意一端进入到指定的建筑中就能够重建桥梁。

还有，在大多数情况下，玩家们可以采取的行动主要就是消除上述所说的动态地图元素。硝烟弥漫、残破不堪的地方有很多，但维修、翻新的地方并不多。

我想我得谨慎一些……我特地使用了“动态地图元素”（dynamic map elements）而不是“动态地形”（dynamic terrain）这个词，因为几乎在所有情况下，地图的实际地形都是不能被修改的。如果地图上有一个不可越过的悬崖，那它在玩家对战过程中依然还是悬崖。相比之下，“动态地图元素”是类似于“因玩家而产生的结构”：它不能移动、可以被摧毁。它在游戏中也起到一定的为战术目的服务的作用，任何玩家都能加以利用。另外，这样的“地图元素”可能是玩家行动的间接结果（重点强调间接！）：一辆废弃车变成了残骸，或者一次猛烈的攻击留下了一个弹坑，诸如此类。

为什么将动态地图元素定义成间接行动的产物在我看来非常关键？我想，归根结底是因为此时双方/所有玩家都必须对变化的战场做出反应，而不是让玩家准备一个变化的战场，逼迫对手做出反应。前段时间我写了一篇关于策略游戏中的行动类别的文章，我觉得很多策略游戏已经有了足够多的准备行动（比如玩家为了让自己在游戏中获得最终的优势而长期重复的某些行动），而游戏地图在多人对战的过程中都是保持静态的，除非有动态的地图元素存在。在我看来，在地图上添加响应式的元素，这是能够产生积极影响的。你得让玩家们保持警惕。

有些游戏，比如《地球2150》，还有最近的Zero-K，确实提供了更加灵活的地形调整选项：制造山峰、在峡谷上建桥梁、挖沟……类似这样的。

虽然这很有意思，但我并不认为竞技策略游戏总是能通过这种提供大量修改地形选项的方式变得更好。就比如说，在《地球2150》中我几乎就没用过地形修改工具。

当然《地球2150》确实是一个“无所不包、一应俱全”的游戏：玩家可以自己设计单位，游戏有“画中画”模式——玩家可以同时观看多个地区的情况，还有一个挖沟系统，为的是让单元在地下隧道里穿梭……这样的例子不胜枚举。在我能想到的RTS游戏中，我个人认为在地形修改方面下了最多功夫的应该是Zero-K。游戏的地形修改系统兼具了战术和策略元素，这让我很感兴趣。虽说我玩得还不够久。

我个人更倾向于有明确的定义和约束的游戏系统，同时还能允许单位之间进行深层次、复杂的互动。而对于这些自由度相对较高的系统，我个人还是有点担忧的，包括那些能够自行设计单位类型的游戏。我发现，比起具有预设定系统的游戏，你在那些实际可行方案/策略其实不怎么多的系统中很容易就能找到“最优”方案，而且这类游戏的复杂度与深度的关系严重不协调，这种复杂性不仅不能强化响应式玩法，还会增加产生反效果的风险。

我想在这里澄清一下：我的意思绝对不是“我反对在RTS游戏中应用可自由操控地形的机制”，我只是对此抱着怀疑态度，目前还没有哪个说法或者实例可以说服我。或许等我的Zero-K游戏时间再长一些以后，我会再回来反馈。

虽然比较二元化，但我更喜欢的是类似于《命令与征服》游戏中桥梁的设计（系列多数都有）。单位可以摧毁桥梁（击杀正在坍塌的桥上的任何东西），然后再由工程师到关联的控制塔里展开重建工作。这就给了双方玩家很大的主宰权，由他们决定游戏地图上何时建造桥梁、怎么建。在我看来，像桥梁或其它可破坏的建筑（如《战锤40K：战争黎明2》中的掩体），它们比一般的地形操控这种笼统的设计互动性更强，也更容易摸索。

我非常重视游戏系统的清晰明了。而且，在我看来，地图上的具体物体，比如建筑物、可以用来躲避的石头、战壕……这些都是玩家可以一目了然的东西。弹坑的边缘可以帮你抵挡炮火的冲击，躲在建筑物里也能起到同样的作用。把建筑点燃，让敌人捞不到任何好处出，或者消灭一堆躲在里面的敌人，嗯……这也是很明确的互动暗示。

总结

无论是我所说的“动态地图元素”“动态地形”还是传统的静态RTS地图，肯定都有正面和反面的实例。

那些经常玩《帝国时代2》或《星际争霸2》的人——也就是追求纯粹竞技的人，往往能够看出地图的限制所在，这会阻碍他们展示技能，让他们提不起竞争动力。就比如说《星际争霸：母巢之战》这个游戏，地图中并没有多少元素会促使冲突事件朝着完全超乎玩家预期的方向发展，或者说在对战过程中，地图的哪些部分会突然变得很重要。

然而，在《命令与征服：重制版》中，地图上泰矿的出现会产生一些影响——这一点在《泰伯利亚之日》中则更为明显，泰矿再生速度加快，杀伤力也随之增加。在更早的游戏中，玩家很难掌控泰矿出现的位置，但随着地图上的泰矿逐渐被清除，步兵们在地图上行动就变得更加安全了，进而对个人战斗产生一定影响。

所以，在我看来，动态地图元素最大的缺点就是基于总体设计目标而言，它们可能会产生一种突兀感。即便如此，我还是得再说一下：《星际争霸2》中的可清理的碎石在一定程度上就算是一种可行的应对方法。

总而言之，我认为在游戏地图上加入动态元素是一件很有益的事，不管是简单地加上阻挡道路的石头，摧毁它打通道路，还是类似防御道具这种更复杂的设计——可以为任何一方所用，需要特殊能力才能摧毁（如手榴弹）。当地图对玩家的行动给出反馈时，它通过给玩家提供新的地图区域来争夺（无论是为了资源，还是为了从对手那里偷取武器），或者删除或增加防御选项来促使玩家用新方法来应对特定区域，又或者是提供应对敌人的新方法，从而进一步增加游戏在响应方面的深度。

我觉得要是RTS游戏的开发者能多赋予地图多一些灵活性、真实性，而不是单纯的静态游戏面板，这样会更好。它们应该随着玩家的行为而演变——坠毁的直升机把草地砸了个坑、建筑被烧毁、处于枪林弹雨中的墙摇摇欲坠……我支持动态地图元素是从机制/系统考虑的，但我想视觉上应该也是很酷的。

关于动态地图元素，你有什么想法？RTS游戏的地图应该像《星际争霸》那样偏静态，还是应该像Relic旗下的游戏那样？像Zero-K、《地球2150》这样可自由操控地形的设计是否过犹不及？

本文由游戏邦编译，转载请注明来源，或咨询微信zhengjintiao

One thing I always love to see in an RTS is when its game maps, or at least portions of them, are able to evolve over time in reaction to the actions players take. To a lesser extent, I also enjoy seeing maps which change over time without player input, to force players to adapt to changing situations and threat profiles, but I feel that has less of a solid case in competitive games.

In many RTS games, especially many of the the classic franchises, game maps are largely static. They may become denuded of resources (like trees) over time, which opens up new movement options to target enemy holdings, but in most cases this is not a major tactical consideration across most competitive matches in those games.

There are tactics and strategy games, however, where the map itself is able to be modified by players in a variety of ways: opening up new attack paths or closing them off, changing which areas of the map players care about and want to contest, or removing options from players in specific geographic areas.

A screenshot from the Steam version of Z which shows what cliffs look like. The blue tank at the top of the image is shooting cliffs to destroy them so that it can pass through.

The oldest game where I remember seeing what I’m calling a ‘dynamic map’ is Z, the retro tactical robot game by Bitmap Brothers. In that game, there are cliffs which block traversal by units (see screenshot above). Infantry can take down the cliffs by throwing grenades at them, which of course depletes the limited supply of those valuable pick-ups. Tanks can also fire on cliffs to destroy them. The presence of destructible cliffs might not have had an outsized impact on the game’s design, but it certainly did on my imagination as a kid.

Some Additional Examples

Relic’s RTS games are more recent examples of games with dynamic map elements. In Dawn of War 2 and Company of Heroes 2, some higher tier units are capable of crushing terrain and cover underfoot or under tread, and some weapons hit hard enough to create craters that can themselves provide cover. Additionally, in these games, when vehicles die they remain behind on the map and can be used as cover or destroyed entirely. Over time in these games, the map devolves into something else, devoid of cover for infantry, covered in craters and the smoking wrecks of tanks and halftracks.

Large units, like the Carnifex, are able to crush map elements by walking through them

While not seen ranked multiplayer any more, Company of Heroes 2 also launched with weather effects on the game map, where at irregular intervals blizzards would occur, freezing water, creating snow drifts which would slow down infantry, and creating hostile environments where infantry would die without access to a heat source. Some weapons, such as flamethrowers, could melt the snow. This wasn’t so much driven by player action, but did force interesting reactions from players in terms of preparing for the blizzards and how the game worked during and even after them. Clearly it wasn’t a widely popular system, since it ended up being removed from the multiplayer experience.

Additionally in Company of Heroes 2, explosives and some weapons are able to destroy ice under troops and tanks, instantly killing them by submerging them in the frigid water underneath. This occasionally has a dramatic effect in winter maps, in addition to changing how units are forced to move while on ice (to avoid holes in the ice). I believe during blizzards, ice could re-freeze as well, creating a cadence of changes as ice was destroyed and re-frozen.

Tanks breaking through the ice in Company of Heroes 2 is one of my favorite examples of dynamic map interactions

Supreme Commander has a slightly different take on this: In SupCom, when units die, they leave behind a wreck that can be salvaged for resources, seeding the sites of battles with valuable income for whomever reclaims it. This doesn’t change the map itself as much, but does change how players interact with the map and which parts of it might be the most valuable to hold or contest.

Company of Heroes games, and now Iron Harvest, have a similar idea in that when units die they drop either the weapon they’re crewing, or a weapon they’re carrying that then any other infantry squad can appropriate. This allows for both tactical flexibility (since players are able to gain squad types on the fly) and a transfer of resources from one player to the other, since the weapons all cost resources and a player can gain a tool paid for by their opponent at no cost. Actually, C&C 3 does this as well with some vehicles dropping wrecks that can be re-crewed by engineers for quick access to a new unit.

Company of Heroes 2 goes farther with this than any other game I can think of (including C&C3) with de-crewed tanks having the ability to be captured by other players. Since tanks are so powerful and expensive, scoring one off of an opponent is a major gain.
I consider these dropped weapons and crew weapons and tanks to be ‘dynamic map elements’ in exactly the same way that I consider dead units in Supreme Commander to be such: they’re free resources that occur in locations on the map that are the result of combat between players, that can advantage either player/team and cause those areas of the map to become temporarily tactically or strategically important, to say nothing of dead vehicles becoming cover for infantry in these games.

I actually really like Supreme Commander’s approach, and have implemented a similar system in my personal game project: SCRAP mod. In SCRAP, when units die, they decay into resources after spending 3 minutes as a burning wreck, giving players time to jockey for control of those resources before actually being able to mine them.

When units like the Aeon Illuminate’s Czar die, they create obstacles to unit movement that are also valuable sources of income for either player, creating an area of high value on the map that didn’t previously exist

Even StarCraft 2 and Grey Goo have dipped their toe a bit into maps that can evolve over time with the addition of rocks that block certain map access points; and, in StarCraft 2′s case, pillars which can be destroyed to block off access to areas of the map with debris that can itself be destroyed to open up the path again.

Going into Detail about ‘Terrain’

In most cases, implementations of dynamic map elements are mainly focused on how units traverse the game space. Destructible bridges are a good example of this – in several of the Command and Conquer games, Engineers are capable of re-building bridges by entering a designated structure at either end of the bridge.

Also in most cases, the majority of actions players can take is to remove said dynamic map elements from the game. There’s a lot of crushing and burning and demolishing that goes on, and not a lot of growing or shoring up.

Builder units in Earth 2150 can modify map terrain to make bridges, walls, ditches, and more.

I need to be careful here: I’m specifically using the term “dynamic map elements” instead of “dynamic terrain” because in almost no case is the actual terrain of the map able to be modified. If there’s an impassable cliff, it remains a cliff for the duration of a match. By contrast, a ‘dynamic map element’ is in some ways similar to a player-produced structure: it’s something that cannot move, that can be destroyed, but in the case of a dynamic map element it also serves some tactical purpose in the game but can be utilized by either/any player. Alternately, such ‘map elements’ might be an indirect (to me, it’s important that the reaction be indirect!) result of player action: a dead vehicle turning into a wreck, or a heavy attack leaving a crater, that sort of thing.

Why is it important to me that dynamic map elements be created as the result of indirect action? That’s a really good question. I think, ultimately, it’s because at that point both/all players must react to the changing battlefield as opposed to having the players prepare a changing battlefield to force their opponent to react in order to deal with. I wrote a while ago about categories of action in strategy gaming, and I feel that strategy games have tended to have a sufficient amount of preparatory actions in them (e.g. actions that players build up over time in order to give themselves an eventual leg up in the game) and game maps in particular remain pretty static over the course of any competitive multiplayer match, unless dynamic map elements are present. Adding reactive elements to the map, to me, is a positive thing. Gotta keep players on their toes.

Some games, such as Earth 2150 and, more recently, Zero-K, do allow for a more free-form modification of terrain itself: making mountains, bridging chasms, digging ditches, that sort of thing.

In Zero-K, terrain manipulation can be a pretty big deal

While really fascinating, I’m not fully convinced that competitive strategy games are always made better by providing players with unlimited freedom to modify the terrain of a map. In Earth 2150, for instance, I rarely if ever made use of the terrain modification tools for any reason.

Of course, Earth 2150 is admittedly an example of ‘kitchen sink’ design: players design their own units, the game has a ‘picture in picture’ mode where the player can watch multiple areas of the map simultaneously, there’s a system for digging and moving units around in underground tunnels on a separate layer of the map… the list goes on. Zero-K is probably the RTS that I can think of which takes terrain modification most seriously. There are tactical and strategic elements to the game’s terrain management system that interest me, even if I haven’t played much of the game yet.

I tend to be more in favor (personally) of game systems that are clearly defined and constrained, while still allowing for deep and complex interactions between units. I tend to be a bit wary of more freeform systems, including ‘design your own units’ type systems in games. I find that it’s often easy to find ‘optimal’ builds in those systems that actually have a smaller number of viable builds/strategies than games with pre-defined systems and also that they’re also ultimately too much complexity buying too little depth, with the added risk of that complexity actually damaging emergent gameplay where it’s trying to foster it instead.

I would like to be 1000% clear here: I’m not saying that I’m against full terrain manipulation in RTS games. I’m just saying that I’m skeptical of it and have yet to be convinced either way. I may report back once I get more hours into Zero-K as to the results of that experience.

While admittedly more binary, I tend to prefer things like how bridges work in (most) C&C games. They can be destroyed by units (killing anything on the collapsing bridge) and rebuilt by an Engineer going into the bridge’s associated control tower. This gives both player a lot of say over when, and how, bridges exist on a game map. Something like bridges or destructible buildings/other terrain objects (like cover in DOW2) to me feels a lot more interactive and straightforward to grok to me than something more nebulous like more general terrain manipulation.

I’m a pretty big proponent of clarity in terms of game systems (you might find this hard to believe if you’ve played my personal mod project, but I digress). And, to me, concrete objects on the map like buildings, rock to hide troops behind, trenches… these are things that a player can understand and interpret clearly. The lip of a crater will protect your troops from incoming fire; holing up in a building will do the same. Setting the building alight to prevent the enemy from using it or to destroy a bunch of enemies holed up inside, well… that’s a pretty clear interaction too.

Wrapping it Up

There’s definitely cases that can be made both in favor of, and in opposition to, both what I’m calling “dynamic map elements,” “dynamic terrain,” and traditional static RTS maps.
Competitive purists: those that mostly play Age of Empires 2 or StarCraft 2, tend to appreciate the relatively limited rough edges that maps provide that get in the way of the expression of their skill and competitive drive. There’s not much in a Brood War map that’s going to mess with a player’s expectations of how different encounters are going to go, for instance, or the parts of the map that are going to matter over the course of a match.

In Command and Conquer Remastered, however, the presence of Tiberium on the map can have some impact (this is more true in Tiberian Sun, where Tiberium regenerates faster and can be more lethal). In the older games, players don’t have much option to control where Tiberium is, but as the maps clear out of Tiberium, they become much safer for infantry to traverse, which can have some impact on the progress of an individual match.

So, to me, the biggest con for dynamic map elements is that they might not fit into the game based on the overall design goals. Though again: even StarCraft 2 has managed to find limited expressions of this sort of thing in the form of destructible debris.

Ultimately, I think it’s a great thing to have dynamic elements on the game map, whether it’s as simple as rocks that block paths, which can be destroyed to open them up, or whether it’s more complex like defensive tools that can serve either player, and be destroyed by abilities (like grenades). When the map responds to player action, it creates emergent depth in the game by giving the players new areas of the map to fight over (whether it’s for resources, or for actual weapons of war to steal from their opponent), or creating new ways to react on certain areas of the map by removing or adding defensive options, or new approaches to dealing with their opponents.

On average, I feel like it would be good for maps in RTS games to feel more like a living place and less like a static game board. They should evolve based on player actions, with crashing helicopters digging up turf, buildings burning down, walls crumbling as shots or vehicles pass through them. I ultimately like this for mechanical/systems reasons, but I imagine it would also be cool visually.

What do you think about the topic of dynamic map elements? Should maps be more static, like in StarCraft, or should they evolve more like in Relic’s RTS? Is more freeform terrain manipulation like Zero-K or Earth 2150 better, or going too far?

(source: gamasutra.com )