April 09, 2018

Traps in tabletop RPGs

Why traps?

Traps often seem like they exist to do the following:

  1. Force the players to say "we check for traps" (or convince/threaten their DM into accepting "we are constantly and always checking for traps!" as a valid "standard operating procedure").
  2. Slow down the party's progress, due to constantly and always checking for traps. (This allows the DM to make more wandering monster checks, thus affording more opportunities to cackle with sadistic glee when the party is jumped by a … <rolls d20> … "no encounter".)
  3. Punish players who don't do #1, by inflicting gruesome injury on their characters, and forcing the party cleric to spend valuable spell slots to heal them.
  4. Force someone in the party (inevitably, the hapless rogue) to spend ranks on Disable Device (the other use of the skill—opening locks—is fully subsumed by the knock spell, rendering rogues useless, although of course they were already useless, right?).
  5. Reduce the party's successful negotiation of the fearsome dungeon hazards known as traps—those intricate brainchildren of the dungeon creator's fiendish intellect—to simple, unadorned die rolls (Disable Device again). How good are you at rolling high numbers on a d20? Pretty good? Great, you can advance through the dungeon. Not so good? Sorry, you have to keep rolling until you roll a high number. But if you roll low enough, something terrible may happen to your character!

Some of the above is true, some of the time. Sometimes it's not. But it usually feels true. Why?

Well, how does interaction with traps usually go?

DM: You are in a hallway. What do you do?
Players: We advance! <seeing the DM hefting a d20> … CONSTANTLY checking for traps, of course!
DM, rolling: You find a trap!
Players, with feigned excitement: Great! Good job, rogue!
DM: <cursory description of the trap> [this part is optional; sometimes it's omitted]
DM: Roll to disable the trap.
Rogue: <rolls>
DM: You have disabled the trap!
Players, apathetically: Yay.

(What was that phrase? Something about a Mechanics' Association…?)

Other variants exist. Sometimes a DM rebels against the above blandness, and tries to "make traps more interesting" by describing their mechanisms and workings in detail. Having done this, the DM looks at the players expectantly, only to find himself having this conversation:

DM: ... and that's what the trap is like. What do you do?
Rogue: I disable it!
DM: How?
Rogue: … with my Disable Device skill, how else?
DM: Ok, but, like, specifically, what do you do? Describe it.
Rogue, exasperated: I don't know, man! I'm not my character! Figuring out how to disable it is my character's job, not mine. What, do you make the fighter describe how exactly he swings his sword when he makes an attack roll? I invested fifteen ranks into Disable Device, my total modifier with all my bonuses is +27, so… I disable it. Somehow. My character's really good at this, he figures it out.
DM: … sigh.

Some DMs give up, at this point. Others, dead set on the notion that traps must be "interesting" but unable to counter the assertion that "my character's really good at this, he figures it out", describe the trap in detail—then, upon a successful Disable Device roll, also describe how the rogue disables the trap. This sort of "dialogue" is usually met with understandable blank stares from the players (watching a DM play D&D against himself is, at best, a slightly bizarre experience), while making the DM question his life choices.

But wait, more absurdity lies ahead! Even if the DM decides to continue performing the solo trap-description act, it all falls down when magic traps arrive on the scene.

Consider: the PCs walk into one end of a 100 foot long dungeon hallway, completely devoid of doors, branching tunnels, adornments, or anything whatsoever except bare walls and a dead end. On the far wall at the end of the hallway is inscribed a magic symbol. It is enchanted to activate whenever any living creature approaches within 60 feet or less. When it activates, the symbol will kill everyone in the hallway.

The rogue, entering the hallway at the head of the party, spies the symbol immediately, and says, "Hold, friends! A magic trap lies ahead! Wait here, while I disable it." His player then rolls a Disable Device check… beats the Difficulty Class of the trap… and the rogue…

Does what? What does it mean to disable this trap? How is it done? Is the rogue disabling it at range, from more than 60 feet away? How? Is that even a thing the Disable Device skill lets a character do? What if the trigger radius was 600 feet? A mile? Does the rogue approach the trap? But that'll make it trigger. Won't it? Does the rogue somehow render himself undetectable to the symbol's magic? How? Is that an ability that rogues get? (Is that what "trapfinding" is?) Does it allow the rogue to simply walk past a trap without disabling it? Is this power applicable in other, non-trap-related, situations? If not, why not? Is there a special dance the rogue does, as he approaches the symbol, that makes it not activate? What is going on here?

Trap disabling is a dissociated mechanic. Dice are rolled, game mechanics are used, but there is no sensible way to translate any of that into a consistent, coherent description of what actually is happening in the game world. Oh, certainly in any particular case a description may be concocted, but it is a post-hoc thing, which may sound plausible at first blush — but either has no bearing whatever on what actually happens in game terms, or it ends up only complicating things (after all, what happens when this explanation turns out to make no sense for the next magic trap?). (Justin Alexander's commentary on dissociated mechanics applies in full here, and I can express his points no more eloquently than he.) To avoid having to face this nonsense head-on, most DMs simply handwave away the details, saying "you disable the trap", and hurry on to the next part of the action. And because doing this is inescapable for magic traps, a DM will usually end up doing the same thing for all traps, having finally given up on "interestingness".

This has a corrosive effect on the game. It breaks immersion: we watch as our characters move through their world, the camera view of our mind's eye following them closely, panning over the critical details of their surroundings, showing us their actions in full Technicolor — until it comes time to handle a trap, and the director says to us: "uh, now, we're going to look away, and blur the view, and, uh, something happens, don't think too hard about it, ah, there we go, all done!" This damages the players' ability to imagine themselves in their characters' place—to roleplay—and reminds them that this is all fake. And, of course, it leads directly and inevitably to that laundry list of complaints at the beginning of this post. If traps have no reality or meaning within the game world, it's hard to see them as anything but annoyances. (In fact, the more the players are pulled out of immersion within their characters and within the world the characters occupy, the more likely it is they will start to see all obstacles facing their characters as annoyances to no good purpose.)

Ok, so what's the alternative?

Obvious answer: don't use traps. At all. This does work, in that it avoids all of the problems just described. Naturally, this is not the answer I chose.

So, again: why traps?

Tradition: Traps have long been so much a part of D&D that their existence and effects are encoded in the design of classes, of spells, of entire campaign worlds. What's a dragon's lair without traps? A lich's stronghold on the Outer Plane of Acheron? The lost tomb of ancient kings? What's White Plume Mountain without the razor-blade pits in the frictionless room, or newbie sorcerers drowning face-down in the mud thanks to a symbol of sleep and a hungry sphinx? What's Castle Ravenloft without a party member being silently teleported into a crypt full of wights, and a disguised wight installed in the victim's place?

Texture: Traps lend a sense of peril to a dungeon delve, the feeling of being in a dangerous place, where you are an unwelcome intruder, and the place itself wishes you ill, and will inflict harm upon you, if you let it. A trap-filled dungeon is not merely another place to have some combats. Pursue the dragon to his lair, and you'll find the tables turned against you; the dragon's mastery of his domain makes your every step potentially your last. The lich whose phylactery you seek has spent a century making his home into death for unwanted guests, and you should fear entering within, even after you've destroyed its owner. Within the peak of Elbrus lies a stronghold of the spell weavers, a strange place of alien geometry and bizarre devices which may do only the gods know what; every object, every surface, is a risk to touch. At its best, a dungeon, creatively furnished with devious traps, can take on a life of its own; it can have a personality, remembered long after its inhabitants have been defeated and forgotten.

Immersion: In a world with teleporting demons and fireball-slinging wizards, the player characters' actions may start to seem increasingly unreal. The characters wander through exotic realms, engage in larger-than-life battles with fantastic monsters, use magic to counter magic, and ward themselves with more magic. The world around them seems to blur and become indistinct, not quite real unless initiative is rolled, painted only in broad strokes otherwise. Traps, done well, force the players to engage directly with the game world, which appears now in sharp focus. Other things may have this effect also—perilous environmental conditions, realistic weather, consistently vivid sensory descriptions—but traps are visceral; they hit home.

Traps tend to have very physical effects: they drop a character down a shaft onto spikes, they send her careening through a slippery chute, they stab at her fingers with cutting blades, they drop stone blocks on her head. The experience of a trap's effects is much easier for the player to imagine from the character's viewpoint than is being affected by a harm spell. This pulls the player into the game world, and into the character's head. For the same reason, well-designed and well-described traps are interactive and interactable: a player can imagine things her character can do with, to, or in a trap, because the trap itself is something imaginable; and the very physicality, the three-dimensionality, of this piece of the game world, means that there is a wide variety of things for a character to do with it.

Challenge, choice, control: People don't just play D&D to be challenged, but challenge is a big part of the game. What is gotten too easily, what is given for nothing, unearned, is not valued; for lack of challenge, all "rewards" taste bland; false "accomplishments" are empty words. And overcoming challenge is its own reward, for it means validation of one's talent and skill: success in D&D demonstrates cleverness, creativity, flair, and other virtues besides. Diversity of challenge both prevents satiety and boredom, and ensures that everyone gets what they like best, at least some of the time. Traps add a new dimension of challenge, one that is unlike the others in the game. And diversity of challenge is itself challenge, forcing characters and parties to be more the Renaissance Man than the narrow specialist.

But "challenge" is not merely "difficulty" or "complexity" or "obstacle". A challenge must be comprehensible, and it must be solvable. To be satisfying, it must allow real, interesting choices; interesting, because their potential outcomes are knowable, and real, because those outcomes are truly different from each other. And a challenge is most exciting to encounter, and most satisfying to solve, when the solution is one of which, and during which, the solver is entirely in control. Such challenges become sought-after opportunities to exercise control, to use one's skills at their best; to win. Well-designed traps, encountered within a game system well-designed to handle them, have all of these qualities.

So what kind of game system is that—"well-designed to handle traps"? The old-school, perhaps? How were traps handled in the olden days? Well, first the trap had to be found; without the Search skill, that meant describing your character's actions: "I walk forward slowly, tapping my staff on the floor before me, side-to-side across the width of the corridor"; "I carefully rap each section of the wooden door with my gauntlet, to see if any part sounds like it might be hollow"; etc.1 The DM might say, "One of the floor tiles just ahead wobbles a tiny bit as you tap it." Further investigation suggests it's a pressure plate, a likely trigger for a trap, of what sort—the PCs don't know. The players brainstorm a solution. "We'll jam it! Wedge a few wooden stakes at the edge, that'll fix it so the plate won't lower!" They announce that their characters do this very thing—"yep," says the DM, "you've wedged it real good"—and then walk forward. Then it's up to the DM: did it work? Or is hilarity about to ensue? The players will soon find out, but anyway it's out of their hands… Meanwhile, the DM is laughing inside, at all the ways in which the plan is foolish, and impractical, and anyway doomed from the get-go.

There are three problems with a system like that, one of which is not a problem, and two of which are. Problem one: in the old school, a 20th level rogue is just as good at finding and disabling traps1 as a 1st level rogue, or a 1st level fighter; because this sort of challenge doesn't rely on the character's numbers, it doesn't scale with character level.2 This is not actually a problem. Where is it written that all challenges in the game must be directly dependent on character level? If a lower-level character can defeat a trap, with clever play instead of abstract numbers, as well as a higher-level one can, then call that a feature of the system.

Problem two: action resolution is entirely at the whim of the DM; he determines, by fiat, whether a trap will be found, and whether the players' method of disabling it will work. The DM might justify his ruling to the players, but it's still fiat. This may be fine for some things, but for interactions with complex, physical systems, like traps, it's strange, and often makes the players' mental image of the game world diverge from what's in the DM's head. Worse, while the DM may well be a walking perfect physics simulator, the players must also trust in this fact; if they doubt it, then it begins to seem as if the challenge is not "solve this trap", but "be persuasive to the DM". That's not a fun game for anyone.

Problem three: some players just plain don't like the cognitive challenge of visualizing a trap, based on the DM's description, analyzing it, brainstorming ways to disable it, and determining the best solution. Fine and well; people enjoy different things. Does this mean that traps, in their entirety, that whole part of the game and all its implications, can never be fun for such players?

I say that these problems can be solved. Device lore (see below) is part of my solution.

The full solution looks like this: The Disable Device skill represents the physical skill of jamming levers and wheels, threading wires through mechanisms, striking a clockwork device just right, so the gear shafts warp and the device misfires. It's training, practice, muscle memory; in other words: execution. Disable Device does not reveal, nor substitute for, a plan for just what the character is trying to do: disable the trap? How, exactly? Say what your character does, and roll Disable Device to find out how well he does it; but the skill doesn't give you the "what". (After all, Disable Device is tied to Dexterity, not to Intelligence!)

That's where device lore comes in. A successful device lore check tells you what you can do to "solve" the trap, what options you have. Higher rolls reveal more options; simpler solutions, more convenient ones; solutions that don't involve modifying or breaking the device at all. Device lore steps in for the player's need to analyze the trap himself. The player rolls the check, the DM reports the results, and the player considers the options thus revealed and decides what his character will do; then, Disable Device determines how well the characters does it.

Thus when a party comes across a trap, their interaction with it can go in one of four ways:

Scenario 0: The characters don't see the trap before blundering into it. The trap is triggered, and the PCs are exposed to its effects. Perhaps some party members make their saves, if the traps allows a save; perhaps not. In any case, the consequences of the trap's triggering take place.

In the other three scenarios, the characters detect the trap (by using the Search skill or otherwise); the DM then thoroughly describes just what the characters find, what they see—the physical nature of the trap. Then–

Scenario 1: The players analyze the trap, based on what their characters can see of it, and come up with a solution: a way to disable it, or "solve" it in some other way. The characters carry out the players' plan. How well they succeed now depends on the dice, the number of Disable Device ranks of the party's trap-handler, the complexity of the trap, and other factors of a game-mechanical nature.

Scenario 2: The party's rogue3 rolls a successful device lore check. The DM provides the rogue's player with their character's analysis of the trap, which includes one or more potential solutions—approaches to disabling or bypassing the trap. If the check result was high enough to get multiple potential solutions, then these may differ in success chance, in time required to implement them, in resources which must be expended, in danger, and in any number of other things. This all the DM also conveys. The players, weighing their options, decide which approach to take. The characters carry out the players' chosen plan. How well they succeed now, again, depends on the dice, and the rogue's (or another party member's!) Disable Device ranks, the complexity of the trap, and all the same other factors as in the first scenario.

Scenario 3: The party has no rogue3, nor are the players able (or willing) to analyze the trap and solve it themselves. The party cannot disable the trap, nor can they rig the trap to bypass it safely. They must find some other way of handling this challenge. Perhaps the wizard casts dimension door to teleport the party past the trapped hallway; perhaps the bard uses a staff of passage to create a phase door through the wall; perhaps the rogue pulls a bear out of her bag of tricks and has it trigger the trap, or the fighter triggers it himself—how bad can it be? Or maybe the characters simply decide to avoid this part of the dungeon, or this treasure chamber, for the time being.

The last piece of my solution is more subtle, made of the confluence of many factors. In the original, Gygaxian, vision4, traps are not a "hard barrier", which the PCs must disable if they're to progress through the dungeon, or even survive it. Traps happen; the clever and cautious party avoids most of them, but even for the most careful dungeon-delvers, some traps are unavoidable. The characters must simply deal competently with the trap's effects, and any one trap is not a game-ender; real failure only comes when the party takes a reckless attitude toward the whole dungeon, falling for trap after trap, and eventually succumbing.5 And in the Worlds of Adventure campaign, not even death ends the game; after losing one of their number to a careless encounter with a scything blade, the party returns to the City and has the character resurrected—an expense covered by resurrection insurance from the Argos Trade Consortium, which the prudent adventurer has, of course, seen fit to purchase. And if not… well, there's always a new character to roll. Isn't there a monk you've been wanting to try?

To summarize: traps in the Worlds of Adventure campaign are a common form of challenge, to be handled by the players and the characters, with robust game mechanics designed for the purpose. Traps, just like other challenges in the game, test the players' creativity and cleverness, and their skill at building effective characters and effective parties. The characters' game-mechanical abilities work in concert with the players' ingenuity; greater weight may be put on the former or the latter, depending on how the players choose to play, and how they've built their characters. Traps, as integral, physical parts of the simulated game world, may be be handled in many ways, on many levels—with trap-specific game mechanics, with general character abilities (magical or mundane), with strategic and tactical thinking—according to the players' preferred style and approach. The player characters may thus expect to regularly encounter traps in their excursions into dungeons across the worlds.

Postscript: Magical Traps

Many parts of the solution outlined above speak of physical or mechanical traps, but the device lore ability mentions magical traps as well. What of them?

Magical traps are of two kinds: spells that create trap-like effects, and non-spell traps that have magic triggering "mechanisms", magic effects, or both. The first kind is generally well enough described (as are most spells in modern D&D-type systems) that they may be treated much like mechanisms: the spell has a clearly described effect; how spells interact with other things is also well defined; thus the players can easily reason about the spell and the trap it creates.

The second kind—"traps" where the trigger, the effect, or both, are magical in nature, and do not necessarily duplicate the effects of any spell (this is most relevant in the case of the trigger)—should, in some cases, not be properly thought of as traps (in the narrow game-mechanical sense) at all. Rather, they are perhaps magical phenomena, that happen to have detrimental effects. They are probably not "disabled" or otherwise handled in anything like the same way that the usual sort of traps are. Perhaps they can be dispelled or disjoined, perhaps a magical keystone must be found to turn them off, or something else… in any case, it's a different category altogether.

In other cases, where the trap is magical in construction, but quite trap-like in behavior (e.g. magical runes that cover every surface of the treasure chamber, that fill the room with sheets of lightning if any words are spoken within), it may still not be possible to disable it; magical means of circumvention (dispel magic, etc.) may be required. In any case, a successful device lore check will reveal these facts about the trap (as may a Spellcraft check).


1 To the objection that thieves in AD&D had a trap-finding ability, I quote this from the 1st edition Player's Handbook, the thief class listing, page 27: "Finding/removing traps pertains to relatively small mechanical devices such as poisoned needles, spring blades, and the like. Finding is accomplished by inspection, and they are nullified by mechanical removal or by being rendered harmless." In other words: those traps which are handled by abstract game mechanic are only and exactly those whose construction and operation is too esoteric and intricate to imaginably describe, or to plausibly defeat for one who is not, in real life, a lock-picker or similar specialist.

2 Actually, magical (or even mundane!) equipment, and various character abilities, may quite plausibly help with such "naturalistic" trap-handling, and higher-level characters have more of these things, so chance of success does scale with level, after a fashion; it just doesn't scale in a clear, obvious, numerical way.

3 It need not be a member of the rogue class, but may be any character with the device lore class feature.

4 The 1st edition Player's Handbook again, page 103: "Traps, Tricks, and Encounters".

5 The Tomb of Horrors, the most famous of all trap dungeons, is an outlier; there, a greater than usual degree of paranoia is called for. But not even all of the Tomb's traps are deadly! (Some are merely embarrassing.)

Appendix: Device lore

A rogue may make a special device lore check, with a bonus equal to his rogue level + his Intelligence modifier, to see whether he can comprehend the nature and workings of a trap, and come up with ideas on how to disable it, or understand how to bypass it. (Device lore also applies to mechanisms and devices that are not traps.) (If the rogue has 5 or more ranks in Knowledge (engineering), he gains a +2 bonus on device lore checks concerning mechanical traps, but not magical ones.)

A successful device lore check will not allow the rogue to disable or bypass the trap, only reveal methods for doing so. A successful Disable Device check is still needed in order to disable a device. (Bypassing a trap or other device may involve the use of other skills or abilities, or no skill checks at all, depending on the specific nature of the device and other aspects of the situation.)

The Difficulty Class for the device lore check depends on the type and complexity of the device or trap, as shown on the table below.

Complexity of deviceExampleDevice lore DC
TrivialPit trap5
BasicArrow trap10
Moderate 15
Elaborate 20
Intricate 25
Fiendish 30
Impossible 40
Magic traps1Symbol of death25 + spell level

Magic Traps: Most magic traps cannot be disabled via mechanical means, only bypassed. It may be possible to dispel or otherwise counter them with magic, however. A successful device lore check reveals all of this information about a given magic trap. Additionally, making a successful Spellcraft check against the device lore DC of the magic trap reveals the magical properties of the trap (see the Spellcraft skill description for details), and grants a +2 bonus on the device lore check.

For every 5 points by which the device lore check result beats the Difficulty Class of the device, it reveals another method for disabling or bypassing the trap. Higher check results reveal superior (quicker, more efficient, etc.) methods.

It takes one round to make a device lore check. A rogue may take 10 or take 20 on the check; the normal rules for taking 10 and taking 20 apply.

A character without the device lore ability may make an "untrained" version of this check (which is just an Intelligence check), but only for devices of moderate or lower complexity (device lore check DC of 15 or less).

A character with the device lore ability also gains a +2 competence bonus on Search checks to discover relatively small mechanical traps and devices such as poisoned needles, spring blades, and the like. This bonus increases to +4 at 10th level.

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