Making Dungeons Make Sense- Part I: Traps

[SirNibbles]

This will be the first part of a series of discussions about dungeons and why most of them make no sense in their design (from a realism point of view).

Why do you put a trap somewhere? You put it there because you don't want someone to get past it.
Why not just build a wall? You don't build a wall because you want some people to be able to get past it.
Why not put a wall with a locked door? People who don't have the key need to be able to get through.
Why not have a guarded gate? You don't have the manpower or it's not worth it for the amount of traffic.

So, you use a trap to prevent baddies from going through an area while allowing allies to pass through easily. You also want this defence to not require constant monitoring.

1. Traps that can't be passed without disabling/triggering them aren't easy for allies to pass.
2. Traps that need to be reset require monitoring.

Ideally, your allies should either be immune to the trap or be able to evade it without any effort.

How do you accomplish this?

1. Natural Immunity
-Blade traps that are higher up than members of your race are tall (for short races)
-Poisons to which your allies are immune (through Mithridatism, natural immunity, or some other poison immunity)
-Traps that don't activate if both sides of the passageway are touched (for creatures with a large armspan)

2. Simple Evasion
-Instructions written in the native language or a simple riddle or both for where/how to step to avoid the trap (the manner of stepping should be simple and not require any particular athletic ability or timing)

3. Magic Traps
-Magic traps which are able to detect and ignore your allies will allow them to pass through safely

My list isn't, nor is it intended to be, an exhaustive one. I'm simply saying certain principles can and should be applied to trap design.

Too often we see traps which are just there for the purpose of killing anyone who tries to get past. If we didn't want anyone to get past, we'd seal the passageway.

_

EDIT: Yes, sometimes trying to kill anyone who wants to get past is perfectly valid. Sometimes, as someone else said, you use a trap that simply marks anyone who passes it, whether it be with mundane methods like paint or mud, or magical methods. My main point was that the dungeon owner needs to think about the brainless mooks/civilians who might have to pass by the trap. Replacing mooks gets expensive when they start to catch on that they die after 1 day on the job.

The use of a trap as an alarm is also something extremely valuable that should've been mentioned.

Thanks everyone for the comments.

[Gildedragon]

there is one situation where the murder trap is meant to kill whoever goes through:
when the passageway in which the trap is is a trap in and of itself.
A passageway with a well concealed trap presents a path of least resistance, which invaders are likelier to use instead of looking for the well hidden "service" corridors.
This is particularly the case with fortified underground villages or settlements (think for kobolds or dwarves).

Invader comes, goes down the murder hall, and you've ideally taken out some of their forces before they engaged one.

Also there's the Ancient Tomb traps: boobytrapped for preserving the treasures within. No one is supposed to go through, but walls and seals can be broken: best kill any trespassers. (IRL example: iron dust in egyptian tombs)

[VonMuller]

I agree with both of you. Think about Dwarf Fortress (the videogame). Player's build traps almost exclusively to funnel enemies through them.

Great post, btw.

[Bucky]

One of my favorite low level traps is the color spray and ghost sound trap. It's a minor nuisance if one of the residents accidentally triggers it, but a much larger one for an intruder.

Another use for traps is protecting places that are necessary but not meant for passage, for example an electric shock trap in the chimney to deal with people trying to climb it.

[OldTrees1]

Addendums for the opening post:

Why not put a wall with a locked door? People who don't have the key need to be able to get through.
AND Some people that can get past a lock should not be allowed through.

2. Simple Evasion
... Instructions on how to get past might not be located next to the trap. They might be covered in a security pamphlet or ancient diary. This is not to say a forgetful minion won't scratch a note next to the trap.



Traps should also be designed based on who you expect to reach the trap.

If the trap is the first layer of defense it will encounter all the unwanted (Joe the village idiot, Sally the little girl, & Jane Doe the master thief) and should react as you would want to reach to anyone (might be a non lethal trap if you don't want to hurt Sally).

If the trap is deeper inside your defenses, then you can expect the unwanted to be more cunning. It might be okay to make the trap such that Jane Doe has a higher chance to fall victim but neither Joe nor Sally would trigger the trap.

Sidenote: Some of your minions might be like Joe or Sally. If so then trap design is trickier.

[Azoth]

Don't forget those designed to protect other traps. The ever classic double trap. They are harmless until you unsuccessfully tamper with the initial mechanism.

I do suppose protect may be the wrong term. Alot of the examples I can think of tend to be force amplifiers for the initial trap.

[Albertus Magus]

I'll leave a Link to a short and beautiful treatise about traps (https://www.reddit.com/r/DnDBehindTheScreen/comments/5r3pzg/traps_101/) here; take particular note of the "bait" section.

[noob]

Well often adventurers dig through walls and then you need to trap every wall to be sure to not have your entire dungeon ruined by the holes.

[Gildedragon]

Well often adventurers dig through walls and then you need to trap every wall to be sure to not have your entire dungeon ruined by the holes.

Make the walls load bearing to absolutely 0 margin of error.
Knock a wall down and the roof comes crashing down

[Starbuck_II]

Make the walls load bearing to absolutely 0 margin of error.
Knock a wall down and the roof comes crashing down
It is a simple Architecture/Engineering check DC to know which is load bearing.

[Gildedragon]

It is a simple Architecture/Engineering check DC to know which is load bearing.

That's the thing. If one realizes they're all bearing loads then they're forced to go through the hallways

[Coidzor]

Make the walls load bearing to absolutely 0 margin of error.
Knock a wall down and the roof comes crashing down

That can be problematic to the use and operation of your lair of evil.

[SirNibbles]

That can be problematic to the use and operation of your lair of evil.

When I say use a wall to stop people getting through, I mean the way the US are completely sealing underground tunnels with concrete to prevent drug-smuggling. They're not putting up a layer of brick and mortar- they're completely filling in the tunnels.

That's not something you can dig through without many weeks of labour.

In an evil lair, especially if it's underground, it'd be better to not have a passageway dug at all if you don't want people going down the passageway.

[Psyren]

Too often we see traps which are just there for the purpose of killing anyone who tries to get past. If we didn't want anyone to get past, we'd seal the passageway.

Except that is a legitimate use for traps too - converting intruders into a resource. For example, a trap that minces up adventurers to feed some kind of monster, or one that extracts their souls as an energy source, or even both. Sealing a passage won't accomplish that objective.

I agree that too many traps are used this way, but it's not unrealistic for some to be.

[Coidzor]

When I say use a wall to stop people getting through, I mean the way the US are completely sealing underground tunnels with concrete to prevent drug-smuggling. They're not putting up a layer of brick and mortar- they're completely filling in the tunnels.

That's not something you can dig through without many weeks of labour.

In an evil lair, especially if it's underground, it'd be better to not have a passageway dug at all if you don't want people going down the passageway.

Indeed, but if your evil lair is set up so that it collapses from any real damage to your walls, gonna have a real risk of enemies deciding to just bring your fortress down on your head. Or accidentally doing so while assaulting your location if any siege weaponry can be brought to bear.

[Afgncaap5]

Ahh, I always appreciate a reminder to rethink why a given trap or dungeon is the way it is. The suggestion about the riddle in the native language reminds me of one of my favorite sorts of riddles: the one requiring specialized knowledge.

It's a bit cheap, but it allows the placement of a riddle in a dungeon that isn't a ten minute derailment while the players try to figure things out. If the riddle references an ancient in-universe legend, myth, rumor, or story (such as the battle between dwarves and goblines that happened two centuries prior), it's likely to stump those who don't have ranks in Knowledge (History).

[ross]

First lever opens floodgate to the magma chamber, flooding all entrance hallways and the surrounding countryside. Hitting it again closes floodgate.
Second lever opens drains to drain magma. Hit it again to close.
Third lever engages pumps to refill chamber from magma sea. Hit again to disengage.
All three levers contained in one room, manned in four-hour shifts, so you never have more than one dude away from his job / family / bed. Allowed and encouraged to bring snacks and magazines.
Enemies are detected by war animals stationed at every entrance, along with patrols and pressure plates as redundant fail-safes. (The pressure plates cause an alarm to sound in the lever room.)
Anyone who releases magma that kills enemies is rewarded with better food and a week off of work with full pay; but a magma release for no reason, or that kills friendlies, is harshly punished.

This is, of course, for a fortress that's actively being used by a community, not an abandoned ruin or sacrificial chamber. Naturally, reclusive evil weirdos don't have as many options.

[John Longarrow]

One other use for traps is to allow defenders to engage intruders without opening themselves up to direct attack, at least normally.

Kobold archers are on a ledge overlooking the great hall.
All of the area at the base of the wall the ledge is on is trapped.

Intruders can either trade shots with the kobolds (kobolds can fall back if needed) OR they try to close. If they close they hit the traps.

Another fun one is the get-away trap. 5x5 spot with a 5 foot deep pit trap. Step on it and your dropped into a space that allows you access to a 5 foot tall passage that is otherwise hidden away. If the party disables the trap without setting it off, they can't get to the passage. Bad guy knows where it is and will fall back to that spot, set off the trap, and fall 5 feet before heading down the passage.

Once bad guy goes far enough down the passage another trap springs sealing off said passage. This also does wonders for splitting a party that isn't prepared... :redcloak:

[oxybe]

That's the thing. If one realizes they're all bearing loads then they're forced to go through the hallways

"Problem's in here?"
"Problem's in there, yup."
"Load bearing wall?"
"Yup."
"All of them?"
"Seal 'em in and keep an eye for people leaving secret exits?"
"You got it."

[Fouredged Sword]

One thing traps are commonly used for is to provide low cost protections for times when more expansive protections are simply not plausible. Yes, a full palisade is the ideal for defending a camp, but unless you are a roman army you are unlikely to be able to make on every single day when on the move. On the other hand, just stacking some logs and rocks in an unstable pile and attaching a tripwire to pull out a linchpin can act a little extra safety at night. Anything that trips the trap causes a loud noise.

No string? Well if you have a shovel you can dig some quick anklebreakers along paths you suspect someone will attempt to come from. These are quick pit traps that are about 9" around and 9-18" deep. Cut the sod carefully and replace it with a few sticks to hold the bottom up and it looks just like flat ground. Stepping on it will surely trip and possibly break the ankle of whoever is coming.

That's just the thing. Many traps are cheap and when you cannot build fortifications and lack the manpower to provide more active defenses traps can provide an edge.

Finally, traps are useful force multipliers. A pair of kobold archers are much safer behind a pit trap that will catch the barbarian before he can complete his charge.

[weckar]

Traps, unlike walls, usually mark or detain those who tried to pass but failed. It thereby allows interrogation or punishment at a later moment.

Another common purpose for traps is as "tests of ability". Here there is not a specific subset of people who should be able to pass, but a variable subset depending on competence.

[Starbuck_II]

One thing traps are commonly used for is to provide low cost protections for times when more expansive protections are simply not plausible. Yes, a full palisade is the ideal for defending a camp, but unless you are a roman army you are unlikely to be able to make on every single day when on the move. On the other hand, just stacking some logs and rocks in an unstable pile and attaching a tripwire to pull out a linchpin can act a little extra safety at night. Anything that trips the trap causes a loud noise.

No string? Well if you have a shovel you can dig some quick anklebreakers along paths you suspect someone will attempt to come from. These are quick pit traps that are about 9" around and 9-18" deep. Cut the sod carefully and replace it with a few sticks to hold the bottom up and it looks just like flat ground. Stepping on it will surely trip and possibly break the ankle of whoever is coming.

That's just the thing. Many traps are cheap and when you cannot build fortifications and lack the manpower to provide more active defenses traps can provide an edge.

Finally, traps are useful force multipliers. A pair of kobold archers are much safer behind a pit trap that will catch the barbarian before he can complete his charge.

Not in D&D, traps are worth whole adventures. I mean, have you seen the trap prices?

Kobolds would be rich if they would stop wasting all their money on booze and traps.

[Fouredged Sword]

Not in D&D, traps are worth whole adventures. I mean, have you seen the trap prices?

Kobolds would be rich if they would stop wasting all their money on booze and traps.

This is something that I have always felt was underdeveloped in 3.5. There should be three catagories of traps: Simple, Complex, and Magic.

Simple traps should cost less than 10gp and be a matter of minutes to set up unless they involve a lot of brute labor. Setting a branches and leaf litter pit trap over a pit is 10 minutes of work and costs nothing. Adding wooden spikes, if you have an ax or cutting tool, should be another hour maybe. An alarm trip-line with a bell or even just improvised sounds should also be trivial to make. There should be a hide check to determine how hidden the trap is and maybe a survival check to scrounge resources and maybe a craft Trapsmith check to make it, but nothing over a DC 10 craft check, as it is literally a few knots and bracing sticks and cutting points on sticks.

It would make playing a ranger, scout, or wilderness themed rogue so much more fun.