Finding Traps Stinks - Or Am I Doing It Wrong?

[Pbartender]

Thoughts? Comments? Snark?

You're looking at the problem from the wrong point of view. The problem is not really passive checks, but the simple fundamentals behind how traps have always been placed and been presented.

The problem lies in the fact that, as a player, it is difficult to tell when you should or should not be looking for traps. Historically, traps gets placed in adventures in all sorts of silly, strange places where you wouldn't expect them... In the middle of a well traveled hallway, for example. If the players don't know where to reasonably expect to look for traps, they start to look anywhere and everywhere. And that slows the game down terribly, as the players makes a perception check for every door, chest, closet, cupboard, dead body and five foot square section of floor.

Passive checks were implemented, because people kept complaining about that sort of thing.

So, there's two things you can do, both of them are more about changing your point of view with regards to traps, how you place tham and how you describe and narrate them, rather than any real rules changes.

First, put traps in places that make sense. The purpose of a trap is to A) ambush an enemy someplace you know the enemy will be, but not when or B) protect something or someplace without having to spend manpower to set a guard. Also, if you or your allies use the trapped area frequently, the trap should not be deadly, instead aim for traps that warn and alert.

Second, when designing traps, consider three categories of traps...

First are those that will always be found by your most perceptive PC (DC less than his passive Perception). The big challenge of these traps is not finding them, but bypassing them or disabling them before they get triggered. In that sense, treat passive checks as a sort of "Spidey sense" as far as detecting traps goes. The character notices some small detail that doesn't quite fit the surroundings, which should make the player sit up and take notice. At that point, as long as the player decides to look for something, let them find it automatically -- they've already beat the DC after all. If they ignore the clue, tough luck. The tension comes from the fact the trap is known, but untriggered.

Second, there are those that the best player has some chance of finding (DC greater than passive, but less than Perception+20). These should always be in places you'd expect to find them... Chests, at the perimeter of an encampment, the tomb of a ancient and famous king, and so on. The challenge here is in the finding. What can be fun here, is having multiple traps of the same type -- a minefield might be a good example. The characters blunder into the first trap and set it off. They might suspect there's more, but don't know exactly where. The tension comes from knowing a trap potentially exists, but it's unfound.

Last, there are those are not meant to be found (DC greater than Perception+20). The challenge here comes from the triggered effect... Land slides, rooms filling with water, rolling boulders, slowly closing slabs of stone, lowering ceilings, spreading fire, seeping poison gas, etc. This is a great time for a trap triggered skill challenge, with the dramatic tension coming from the time-sensitive nature of your imminent death.

 

[TarionzCousin]

I'm pretty sure there's a mechanic for finding traps by spending a healing surge...

If you or anyone can find it, you'll win the XP prize!

The problem is more basic - when does the DM call for a skill check, and why?

Depending on your answer, you will arrive at different solutions. The one I have for my game (when there's a conflict, roll dice) works for me.

For example: In my game, only when a PC takes an action to look for traps (ie. there is a conflict between the PC and the environment) do we need to roll.

I believe that this is the standard 4E approach, too: PC's only roll when they say "I'm looking for traps," or "I make a Perception check."

And in actuality, the 4E method is no really different than 1E or 2E. The only difference is that back then the Thief (and only the Thief) would roll percentile dice to try and find a trap, and percentile dice to disarm it. So it's the same as today (two die rolls), except you no longer have to be specifically a single class to attempt it.

Except that in 1E and 2E the chance of finding the trap depended upon how good the thief was at "Find Traps."

In 4E, someone either automatically finds a trap or they have a poor chance to find it. The best a rogue can do for a trap with a DC higher than her Passive Perception is 50%.

That is my problem. It's either 100% or ≤50%. The rogue never has a 60% chance or a 75% chance to find a trap.

Note: Once again I can't disagree with anything Pbartender has written because he is spot on.

 

[Aspeon]

If you or anyone can find it, you'll win the XP prize!

The best I could do in a skim of the PHB is the Detect Secret Doors ritual, which gives a massive bonus to detect secret doors and not traps. Wouldn't be surprised if there's another ritual that does it.

In 4E, someone either automatically finds a trap or they have a poor chance to find it. The best a rogue can do for a trap with a DC higher than her Passive Perception is 50%.

That is my problem. It's either 100% or ≤50%. The rogue never has a 60% chance or a 75% chance to find a trap.

The DMG1's pretty specific about getting passive Perception, or making active checks if nobody sees it with passive. One potential mitigating factor is that when they make active checks, if everybody's looking (and somebody has Perception close to the rogue) or using Aid Another, they may have a better than 50% chance on the active check- it's not much, though. Other than that, you need a houserule of some sort:

1. Always roll one side or the other when there's a passive check that'd matter. im_robertb's suggestion of rolling the trap's Stealth, or just rolling the PC's Perception behind the scenes would work. If you want a compromise, you could say that if two PCs have sufficient passive Perception, they auto-detect (Since they both have a 50% chance of detecting), otherwise they have to roll.
2. Houserule that passive checks don't happen, and PCs have to actually search for traps. This leads to the "search every square" mentality unless your trap placement makes sense- this is what we're doing in my current game, but since the game's Tomb Of Horrors search every square is entirely valid.

 

[Mouseferatu]

I'm pretty sure there's a mechanic for finding traps by spending a healing surge...

Yep. It works like this:

Step. Step. Click.

THRASH-SLICE-CUT-TEAR-REND!

"Uh, hey, guys? There was a trap there. Ow, my hit points..."

IOW, it's called stumbling into it and then healing yourself afterward.

 

[Klaus]

Yep. It works like this:

Step. Step. Click.

THRASH-SLICE-CUT-TEAR-REND!

"Uh, hey, guys? There was a trap there. Ow, my hit points..."

IOW, it's called stumbling into it and then healing yourself afterward.

And there's the time-tested way of bypassing traps: throw the barbarian at it.

 

[nightwyrm]

I think the 4e paradigm for traps has shifted away from being stuff that a rogue finds and disarms and then the party goes on its merry way to traps being an integral part of the terrain during an encounter. Used as such, traps are suppose to not be too difficult to spot. The challenge comes not from avoiding being surprised by the trap, but from avoiding it and/or using it to your advantage during the encounter.

 

[Bold or Stupid]

And there's the time-tested way of bypassing traps: throw the barbarian at it.

Last time we used that the Barbarian volunteered for it... No really.

 

[RangerWickett]

An idea that cropped us from one of Piratecat's recent game logs is to make finding and disabling a trap a skill challenge, potentially one that every PC can help with.

I want rules that play the way that traps show up in stories.

If it's a "that chest might have a trap on it" trap, one or two guys creep forward. Then they examine the chest, and either spot and try to disable the trap, or see no threat and decide whether to take the risk.

If it's a "look out, boulder!" trap, maybe the group spots it in advance, in which case they have to figure out how to get around it, or set it off and try to avoid getting hurt. If they don't spot it and accidentally trigger it, there's an instant where maybe they can duck into a safe cubby or divert the boulder's course somehow so it misses the party. If all that fails, the party gets thumped.

If it's a "we're slowly being crushed by this room" trap, you might spot it in advance so you can avoid it or set it off safely. But if that fails and you're trapped, the group scrambles to hold the walls apart while the rogue figures out how to break the mechanism.

Likewise, if it’s an “I’ve been snagged by a meat hook and pinned to a butcher factory conveyor belt” trap, you and your friends can struggle to free you before you’re sliced into prime cuts.

(Note, I probably have the math off; this was off the top of my head.)

Encountering a Trap
[sblock]The first thing to determine is whether the party detects the trap or sets it off. After that, defeating the trap involves a two-step skill challenge – understanding, to determine if you know the trap works, and avoidance, to keep the trap from harming you and your allies.

In each stage, involved PCs make skill checks. If they fail, the trap gets to attack at full strength. If they succeed enough skill checks for a partial success, the trap attacks at lesser strength. And if they get the full requisite number of successes, the trap harms them not at all.

Unlike normal 4e D&D, if a trap triggers in this system, it does not immediately make it’s attack. The PCs have a chance for last minute reactions to thwart or mitigate the trap. To balance this, however, trap damage is significantly higher. An average trap can bloody a PC in a single strike, and a Trap of Doom (one that gives the PCs a few rounds of warning before it attacks) can potentially kill an equal-level PC.[/sblock]


Detecting a Trap
[sblock]Typically traps with a single target aim at whatever spot the triggering mechanism is in. Traps that affect an area usually have the trigger at a bottleneck point at the far side of the targeted area, to increase the odds of getting multiple people into the area before someone sets it off.

If a player is suspicious and wants his character to search an item or area for traps, secretly roll a Perception check for him. If the check fails, the character is not aware of any trap, but the trap won't trigger unless he takes an appropriate action like opening the chest, pulling the lever, or stepping through the square with the trip wire.

If a player takes the appropriate action that would trigger the trap (regardless of whether he was suspicious or oblivious), compare his character's Passive Perception to the trap's detection DC. If he succeeds, he notices the danger at the last second. If he fails, the trap triggers. [/sblock]


Defeating a Trap
[sblock]This skill challenge has two stages - Understanding and Avoidance. The goal is to accumulate enough successes to avoid being affected by the trap. You do not track failures, only successes. The target number depends on the size of the trap. (These rules cover basic instantaneous traps. Look to the end of the post for rules about traps that take a few moments to build up to something lethal.)

Single Target, Instant. Needle on a trapped chest, pit traps, door scythe, etc. Equivalent to a single monster. Success: 3. Partial: 2.

Area, Instant. Rockslide, flame blast, curse. Equivalent to an elite monster. Success: 6. Partial: 4.


Stage One: Understanding
This stage represents figuring out how the trap works -- either over the course of a few rounds to examine a trap you've spotted, or in the split second you have after triggering the trap before it kills you.

If you are in no great rush, any character who can see or otherwise sense the trap can contribute one skill check by spending a few rounds.

If you have already triggered the trap, however, or if you have a time pressure, each characters close enough to interact with the trap can contribute one skill check as a free action, and the DCs increase one step (from easy to medium to hard). In either case, each PC can only make one skill check to contribute to this stage of the skill challenge.

Use Arcana for magical traps, Dungeoneering for mechanical ones, Nature for wilderness ones, and possibly Religion for divine (or divinely-themed) traps. Use medium DCs (or hard DCs if there is a time crunch).

If the trap has not been triggered, after this stage the party can choose whether to keep trying to defeat the trap, or to give up. If they want to try again later, they keep their existing checks to understand the trap unless they have gained a level in the interim.

If the party chooses to keep trying to defeat the trap, then at the end of the second stage of the skill challenge they risk triggering the trap and suffering its effects. Of course, if they’ve already triggered the trap, they don’t have a choice.


Stage Two: Avoidance
This stage represents trying to keep the trap from hurting anyone. It usually entails getting close enough to the trap to possibly trigger it, so unlike in stage one, the DCs are the same whether the trap has been triggered already or not. Only characters close enough to interact with the trap can make checks to defeat it.

Use Thievery checks for most mechanical traps, Arcana for most magical traps, with a medium DC.

Depending on the trap’s make-up, other skill checks might be helpful too, but they should normally be against a hard DC. You might make an Acrobatics check if the trap has a deactivation that requires getting into a tight spot, or an Athletics check to shove or pull people out of the way of the trap, grab someone falling into a pit, or hold up a crushing ceiling until people get out of the way. (You can't just use Acrobatics to dodge; that's represented by your AC or Reflex when the trap attacks.) Likewise, PC might have powers that they can use for an automatic success, and certain creative ideas can negate traps entirely.


Results
Every trap should be formatted with two attack entries. For instance:

Flame Blast - Level 1 Trap
Detect Perception DC 18 or Arcana DC 18 (active only)
Understand Arcana DC 18, Disarm Arcana DC 18
Close blast 5
Full Atk: +5 vs. Ref.
…Hit: 3d6+10 fire damage.
…Miss: Half damage.
Partial Atk: +5 vs. Ref.
…Hit: 2d6+3 fire damage.

If the party achieves a full success, the trap has no effect, either because they avoided setting off the trap, or disrupted its magic. If the party achieves a partial success, the trap uses the lesser attack option. If they fail, the trap hits them with its full power. They still earn full XP for surviving the trap, regardless of success or failure.

???? Doom Traps under construction ????



Single Target, of Doom. Cage that traps you

Area, Imminent Doom. Crushing walls, pumping gas, tank full of sharks with laser-beams. Success: 10. Partial: 7. (However, you get more chances to make these checks.)[/sblock]

 

[RangerWickett]

And there's the time-tested way of bypassing traps: throw the barbarian at it.

Like the 3e method of finding secret doors - rub the elf on the walls.

 

[bganon]

If you want a trap that's easy to actively spot but not just automatically detected passively, then you can always be liberal with granting significant "circumstance" bonuses, especially if the rogue looks in the "right place".

Example: there's a covered pit in the middle of the hallway, DC 20 to notice, which beats the Passive Perception of 17. But if the player says "hold on, I check the floor for traps", well, you might give a +4 to their roll because they said "floor".

Another option is multi-stage checks, where the DC to notice that there's something funny is fairly easy (and the passive Perception might give the player this warning automatically), but the DC to locate exactly -what- is "off" might be harder.

Example: the DC to notice something funny is 15, so the character (with passive Perception 17) walking into the hallway automatically notices something isn't right. But the DC to actually find the pit trap is 20, so they need to roll. If the roll succeeds, they notice the pit trap as normal, but if they fail, even though the party will know there's a trap, you don't tell them where it is unless they come up with another way of finding it.

I like the second method, myself. Notice that if the first DC is below the passive Perception, then you're really not doing any extra rolling. The main difference is that instead of traps falling into basically two categories ("auto-found" and "hard to detect and springs without warning"), you've now got a third category of "hard to detect but gives some warning".

You can also do the multi-stage part more literally, and if you make it complex enough it becomes the skill challenge method described by our Ewok friend. But you can get "in between" a bit, with something like:

There's an easily noticable pressure plate on the floor. What does it do? Hard Perception to find what it connects to. If you don't, a Thievery check can jam the plate but this might be unreliable (characters stepping on it make an easy Athletics/Acrobatics check, which triggers the trap if they fail). If you do find the spears in the ceiling that the plate triggers, then disabling those are easier and more permanent. The idea is that this isn't a full-blown skill challenge, but a trap that isn't just completely disabled with a single roll once noticed.