Trap design

xTATTEREDx · +FINE+ · *SUPERIOR* · ≡EXCEPTIONAL≡ · ☼MASTERWORK☼

v52.04 · v0.47.05

This article is about the current version of DF.
Note that some content may still need to be updated.

This page is one of several inter-related articles on the broader topic of defending your fortress and your dwarves. Trap design focuses on the theory and design of complex traps, mechanical systems and other automation for defending your fortress, and also on unusual uses of simple mechanic's traps. For a general overview of the threats that will challenge your fortress and things to consider when preparing a standard defense, see the defense guide. For tips on laying out your architecture to protect your military, see security design. For specific advice on how to get your soldiers prepared for any threat, see military.

For suggestions on disposing of nobles and other unwanted residents, see unfortunate accident.

For a basic overview of how the different machine parts work and work together, see machine component.

For information on catching vermin-sized creatures in animal traps, see trapper.

Introduction

Simple one-tile traps* are just that - they exist only on their own tile, trigger themselves when a target walks onto that one tile, and affect only that one tile. Complex traps and automation rely on linking doors, hatches, floodgates, and bridges to levers or pressure plates, along with machinery to provide the power to run some of the more diabolical designs. When the trigger is activated, it sends a signal to the linked device. That signal is not always as simple as do it now, but it's specifically either to open or to close. By manipulating what does what and when, and what follows from that, impressive results can be achieved.

(* specifically, the stone-fall trap, weapon trap, and cage trap.)

To fully understand how these component objects work individually (before combining them into diabolical and complex combinations), see those main articles.

Basic traps

These are the simple traps that are placed by a mechanic. They require one mechanism but do not require levers or pressure plates. They can be a quick, easy and brutally effective "first defense" for a fledgling fortress, but they can also be combined into key parts of more complex set ups. For tips on using these basic traps effectively, see the Trap Strategies section.

Stone fall trap

This is the easiest trap to build, so you can easily build them in large numbers. Building lots of them is an easy way to earn experience for your mechanic, and add to the depth of your fort's defenses at the same time. Surrounding intersections and stairways is a good way of handling threats that make it inside the fortress, including berserk dwarves.

Weapon trap

The gold standard of lethal traps. This is the only simple trap that works repeatedly without reloading. They do get jammed, however. View the trap with the items in room t mode, and if there's a corpse inside the trap, it's jammed. None of the weapons on a jammed trap will function. It may be wiser to have several weapon traps with fewer weapons, rather than a smaller number of ten-weapon traps.

Using crossbows or other projectile weapons in weapon traps avoids the problem of jamming, but they must be kept loaded with ammo. Mechanics will load them with any ammo that is not forbidden. They will load each until each type of weapon has ten rounds of ammo. Hammers seem to jam less than swords or axes, and spears seem to jam the most. Your dwarves will attempt to unjam traps unless otherwise forbidden.

Cage trap

A very powerful type of trap. Maybe even too powerful - currently, even a wooden or glass cage can hold any creature indefinitely, even trolls and megabeasts. A cage trap never fails, although creatures with the trapavoid tag cannot be captured unless knocked unconscious or webbed first. Use cage traps as your outermost traps to catch the occasional wandering animal, angry wounded elephant or unicorn, or even zombies. Caged animals and enemies will be safely brought to any animal stockpiles you have, but may escape later if you are not careful. For more information, see captured creatures.

Linked traps

These traps require a trigger such as a pressure plate or lever. They will require at least three mechanisms, one for the trigger and two to create the link. The trigger can be located any distance from the trap, typically close for a pressure plate or far away for a lever.

For a system that repeatedly activates automatically and regularly regardless of enemies, see Repeater.

Menacing spikes

Menacing spikes or upright spears appear on the basic mechanic's Trap menu, but must be activated remotely to pop out of the ground and impale anyone standing on that tile. Vast forests of these can make any area a killing field.

While upright spike defense systems never jam, they also do not discriminate. When activated, they will inflict piercing damage on whatever is standing on the tile, whether it be friend or foe (so it's good for nobles). You can use traffic designations to help somewhat. Designate the spike trap tiles as restricted then make a longer path going around the spikes that's designated as high traffic. Pets and merchants/diplomats will probably still get skewered, though.

Trap strategies

These are some basic tricks that can be used with most any trap design, basic or complex.

Bait animals

Enemies will hunt down and kill friendly tame animals wandering outside if they have nothing better to do. Put an expendable animal on a restraint or in a 1x1 pen in some random spot outside, build a few columns around it to reduce the chance of them shooting it, and trap that area to hell and back.

Note that this is a horrible method of getting rid of cats, as they will often adopt a dwarf who will then attempt to free the cat. This may lead to the unfortunate situation of Urist McCatlover getting skewered by an ambush party while on his way to free Mr. Baitykins.

Bait furniture

Building destroyers can be baited by furniture, which they will path to and destroy, if they can. Furniture bait allows you to selectively target building destroyers, to draw them away from other aggressors or to a different trap. This can be useful when, for instance, you'd like to draw a building destroyer like a giant cave spider into a cage trap, but don't want to bother caging all of the other wildlife around it. It can also be useful for trapping monsters with special attacks that you'd rather not see go off, as the building destroyer won't use any special attacks on furniture as it would an animal. For instance, you could use bait furniture to trap a forgotten beast with deadly dust without causing it to spew more contagion.

Bait furniture can be especially effective when used with artifact quality furniture. Artifact furniture cannot be destroyed, but building destroyers will still attempt to path to it, at which point they will ineffectually attempt to destroy the furniture. This makes traps baited with artifact furniture easily reusable.

Trapping efficiently

Crosshair trapping

As the converse of building many traps everywhere, consider instead herding your enemies into a few traps. A cross-hair pattern of walls or impassable channels with an array of traps in the middle gap will increase the usage of each individual trap. This is particularly useful when capturing wildlife. You may also want a few traps near the edges, to catch the creatures that attempt to go around it.

+

^

+

l

e

g

e

n

d

+

▓

+

▓

s

t

o

n

e

/

w

a

l

+

▓

+

^

t

r

a

p

+

▓

+

f

l

o

r

+

▓

+

^

▓

^

+

^

+

^

▓

^

+

^

▓

^

▓

^

+

^

▓

^

+

^

+

^

▓

^

+

▓

+

▓

+

▓

+

▓

+

^

+

Inside corner trapping

If the path where you will place your traps has bends, expect the enemy to take the most direct path - it's not guaranteed, but they will tend to hug the inside of a corner, and rarely detour to a dead-end.

╔

═

║

U

n

l

i

k

e

l

y

p

a

t

h

║

╔

═

U

n

p

r

e

d

i

c

t

a

b

l

e

p

a

t

h

║

"

M

o

s

t

l

i

k

e

l

y

"

p

a

t

h

║

g

║

g

I

n

v

a

d

e

r

║

╚

═

╝

Once in a straight hall, anything is possible, but placing your best (or first) traps on the inside path near "inside" corners (and de-emphasizing outside "dead-end" corners) is the best bet. If two invaders are side-by-side, they will wander, and random actions are always possible, but if you had to guess, this is the way to do it.

Pass trapping

If there are a lot of hills outside, remove most of the ramps, then trap those last few routes. The only way for creatures to get around will be to go through your traps.

░░░░░░░░░░░░░░░░░░
▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲   Before
++++++++++++++++++

░░░░░░░░░░░░░░░░░░
+++++++^▲^++++++++   After
+++++++^^^++++++++

Ford trapping

Have a river or any kind of chasm? Construct a floor over it (not a bridge), then build traps over it. Brooks won't work for this, because everything can already walk over the top of a brook. It also won't work as well in winter on a map that freezes.

+++++++++++░^^░+++++++++++
+++++++++++░^^░+++++++++++
+++++++++++░^^░+++++++++++
~~ ~~ ~~ ~~░^^░~~ ~~ ~~ ~~  Nobody ever said that it had to end at the river banks.
~~ ~~ ~~ ~~░^^░~~ ~~ ~~ ~~  Building walls along the side allows you to make it longer
+++++++++++░^^░+++++++++++  and to fill it with more traps.
+++++++++++░^^░+++++++++++
+++++++++++░^^░+++++++++++

Maze/Labyrinth

Mazes not only look cool, they are very effective traps. Essentially, you want 2 entrances to your fort. One for your dwarves and trade caravans, and another for invaders - the maze. Whenever you are under siege, close the entrance for your dwarves. This leaves a long maze that invaders must go through to path into your fort. This allows the entire invading force to be in the maze when you close off the entrance, sealing them in. With the clever use of bridges, you may divert invaders out of the maze and into your traps/military's arms at a rate you can deal with. If your map doesn't have iron, this will greatly decrease the amount of iron you'd normally lose when the invading force starts losing and flees. NOTE: Unlike real-life mazes, it's best to create yours with a single winding path from the entrance to the exit. Invaders have clairvoyance and will path directly into your fort. A roof is also necessary, as walls mean nothing if they can be climbed over. If you do put traps in the maze itself, put them near the end as invaders will flee if they start getting torn up by traps. (Example(note: bridges are down for access), MS Paint Illustration)

I prefer putting my entrance to my maze right below the entrance to my trade depot, then put a bridge over the opening. If the bridge is down then the access to me depot, bridge raises and the entrance is now the maze. Simplifies the multistep process given in the picture. Be sure to have your maze either safe for your own dwarves to walk through or some other method to help out dwarves that are outside at the start of a siege.

Trap Designs

Bridge and drop traps

Drawbridge trap

Lowering drawbridges on invaders will crush them into nothingness. Known as the 'Dwarven Atom Smasher', bridges will destroy most things with some notable exceptions including jabberers and elephants, who will not only survive unscathed but also destroy the bridge.

Try replacing the side wall of a part of your main entrance with a drawbridge, big enough so it spans the whole hallway. Link the drawbridge to a trigger, and whenever you feel like it activate the trap. This can be done with minimal effort and used to smash invaders, unwanted immigrants, bothersome nobles, or simply to destroy your garbage.

Pit trap

A long retracting bridge in your entrance tunnel, with the pressure plate right in front of the fortress doors. The expression on the face of the point-goblin who reaches them only to watch his comrades plunge to whatever gruesome fate you have prepared for them will be a mental picture to cherish. Remember when designing this trap that bridges do not open until 100 ticks after they've been triggered.

You may also consider linking these bridges to levers for more control, just in case a goblin thief triggers the pressure plate while a caravan is on the bridge. Or, you might consider linking the bridges to a repeater.

Cave-in trap

Supports can be linked to triggers. Building a section of floor that is deliberately held up only by a trapped support allows for an intentional cave-in.

Invaders dropped into a pit can be wounded or killed.
Dropping a floor or wall directly onto any creature will instantly kill it, regardless of its size.
The cave-in will also knock nearby invaders unconscious. This will stun them, and also make them susceptible to simple traps (even if they possess the TRAPAVOID token).
Cave-ins will not reveal invisible invaders, such as ambushers unless it kills them outright, in which case their bodies become visible.

The biggest drawback of this sort of trap is the "reload" process, which can be relatively time consuming. Have a drawbridge that can seal off the work area so your mechanics and masons can reconstruct the setup in peace.

Land mines

In any suitable open area which hasn't been dug out underneath, build a support and an adjacent multi-use pressure plate set to trigger on creatures (but not citizens), link them together, then build floor tiles above the support and pressure plate. When an enemy steps on the pressure plate, the game will pause and recenter the view with the announcement "A section of the cavern has collapsed!", at which point the enemy will be crushed and its companions will be stunned or knocked unconscious by the cloud of dust (though not necessarily revealed, in the case of an ambush).

More "traditional" landmines also exist, taking advantage of a bug. This involves setting a bridge to be deconstructed, then having this order be cancelled, all done while the bridge is in the down position. The bridge will then let fluids through, which with pressurized magma makes it a potent weapon.

Chasm trap

The easiest chasm trap is just a platform connected only by a retractable bridge or grate, and supported by a support, very high up or over a very deep hole. The support is connected to a pressure plate on the platform, which is triggered by invaders.

A uselessly complicated collapsing spiral trap can take out ten goblins at a time. When finished, it looks like this:

+

.

+

.

+

#

+

.

+

╔

═

.

#

=

r

e

t

r

a

c

t

a

b

l

e

b

r

i

d

g

e

.

+

║

+

.

(

o

r

g

r

a

t

e

)

.

+

║

+

╔

═

╗

+

.

+

=

f

l

o

r

.

+

║

+

║

A

+

║

+

.

+

║

+

╚

═

^

║

+

.