View Full Version : DM Help On Trap Design

2016-07-01, 10:08 PM
We all know the tyranny of traps-there's rarely a moment where Rogues go 'Man, remember that trap I disabled so it wouldn't kill us all? Good times.' They're one-shot done deals, and that's it. I've heard little of them in non-D20 systems, since they either throw them out altogether or just deal with them similarly to D&D/Pathfinder, where they're 'Roll to spot the trap, roll to disable the trap, move on with life.' So I'm working on something to redesign traps with, but I'm getting a little stuck on a list of what to do with them.

The first step of this trap redesign is that traps are no longer quite as simple as 'Binary spot success/failure, then binary disable success/failure, then move on.' It is instead 'Probably spot the trap, but do you see how to disable it and/or bypass it? When you disable, do you fail, fail with warning, disable via setting it off, disable completely, or potentially redesign it?' And I know that I'm not doing the best job of explaining this, so let me illustrate with an example of a redesign of a Pathfinder Swinging Axe Trap (http://www.d20pfsrd.com/gamemastering/traps-hazards-and-special-terrains/traps/swinging-axe-trap-cr-1).

Swinging Axe Trap
Type:Mechanical; Perception DC:16, 20, 24; Disable DC:16, 20, 24
Trigger:10-foot long pressure plate will activate horizontal axe 4 feet off the ground when 500 pounds of weight steps on it.
Effect: Atk +10 melee (axe; 1d8+1/3); multiple targets (all targets in a 10-ft. line)

A DC 16 Perception check reveals a deep gouge in the opposite wall, and bloodstains on the ground. A DC 20 Perception check reveals the slit that the axe springs out of, and where to begin disabling the axe. A DC 24 Perception check reveals the pressure plate.
A DC 16 Disable Device DC sets off the trap, but you are not flat-footed. A DC 20 Disable Device disables the pressure plate. A DC 24 Disable Device check allows you to disable the device and retrieve its Masterwork Battleaxe without damaging it.
This trap can be bypassed by not putting 500 pounds of weight on the pressure plate, or by keeping to the edge of the corridor. (A DC 5 Acrobatics check.)

It's a bit more work, but it also helps traps feel like they're more than just some kind of minor hindrance to the players-and with a reward for dismantling traps, they can actually be welcomed in certain groups that encourage the skillmonkeys. (It doesn't have to be as straightforward as 'take the weapon out of the trap' either. Magic traps can give 'attuned ruby dust worth 500 GP to a collector' or whatnot, just give it a reward roughly appropriate for its CR, like any monster would.)

Enforcing the Bypass method for traps also helps with both verisimilitude and not punishing players for taking Disable Device or a Rogue. Now there's an explanation for why the Goblins that go through this hallway to never set this trap off-they just don't weigh enough in that small area, and even if it did, it'd sail right over their heads and they'd wind it back in place. And now even a Rogueless group can get past the trap with some difficulty-it might involve a jump check or just going one at a time, but it can be bypassed.

Now, for the part that gives me trouble-the second part of this trap redesign is Out of Combat and In Combat.

In combat traps are the ones people are more familiar with-they slice, they dice, they julienne fries. They also do more minor things, like trip people, hold them in place for a round, and blind them. They're the zap traps, to steal a phrase from the Angry GM, and their only place is to boost the offensive and defensive capabilities of enemies that would otherwise be unable to stand up to PCs without them. (IE, Kobolds.)

Out of combat traps no longer include zap traps-because who cares if you get hit with 10 damage outside of a fight? Maybe if you're extremely low level, have no access to healing, or you're in a far more grim-and-gritty system, you worry about the ten damage. Otherwise, the Cleric heals you, you take out a wand of cure light wounds, you sit down for a few minutes, or you otherwise get rid of the damage somehow.

So instead, out of combat traps introduce new situations to deal with. They're the giant rock that Indiana Jones has to flee from, the alarm that blares to alert everyone and their grandmother of your presence, the pit in front of the door that deposits the party in front of the gloating villain in their seat of power...but the categories of traps kind of elude me, and here's where I need the help.

I'm looking for categories of 'Introduce a situation,' because it sounds nice and easy until you start thinking about how that works. So far, I have...

Enhance enemy capabilities (Usually in the form of an alarm making them wary, getting armed, moving together...)
Instigate a fight (Summon Creature traps, etc.)
Weaken the party (Debuffs, status effects, disorientation, that sort of thing. This really falls under 'zap trap you care about,' but also makes the next encounter more challenging if there's no easy way to remove it.)
Create a 'Win or Die/Suck' situation (Re:Indiana Jones and the Boulder.)
Create a Restriction (You now have to finish the dungeon in a set amount of time or the explosives go off, the cave is magnetized and you can no longer wield metal weapons here, antimagic field turns on, etc.)

And I'm wondering if people have any more things they'd like to add, or have any critiques of the system I'm suggesting.

2016-07-04, 10:00 PM
I'd also consider the logic of the trap being there. No one wants to dodge boulders on their way to the bathroom, for example, and a trap in a well -used corridor will likely kill off a lot of new recruits who forget it's there. Even an alarm trap needs a way to avoid triggering at every passing spider (otherwise, eventually it will just get ignored). A trap protecting a treasure vault, however, is logical. Also, in most situations a way for the rightful owners to bypass and reset the trap is needed.

2016-07-05, 11:45 AM
My favorite trap involves a room where half of it is covered in pressure plates. When two are pressed, that half of the room moves downwards until it is completely cut off from the the other half, which creates two rooms of half the size each containing roughly half of the standard party. Then each half has an encounter.

2016-07-05, 12:27 PM
The Traps and Treachery books are 2 that you should look over, as they have some pretty neat traps in them. For example;
1. a ladder built into a wall has a false rung that come out when you use it
2. they have a trap that sprays the party with blood and unleashes a few hungry wolves
3. the ever classic snake pit,
4 a shoot that casts reduce person on someone and then dumps them into a cell, if they take to long trying to climb back up the chute the reduce person wears off and the only way out is a trapdoor in the ceiling.

2 of these are encounter traps, the ladder trap can serve as an alarm and the other one is a live capture trap. All of these are pretty neat.