UngeheuerLich
Legend
Don´t forget, you add +2 to the spot DC for beeing far away, so it can make a difference forn some traps. (notice /= notice early enough)
Active Perception and Passive Perception
- Thread starter Oompa
- Start date
AbdulAlhazred
Legend
Basically you're onto the whole nut of the thing there Starfox. There's NOTHING wrong with the active/passive perception system. It is a matter of DMs understanding how to use it in the best way.
Where you have something (trap, secret door, etc) there are 3 possibilities essentially. Either the thing can (and thus will) be spotted by the passive perception of a party member. These kinds of 'hidden things' are only "hidden for dramatic effect" as they aren't really hidden at all. This could be like Starfox says a tactical trap where the thing really just serves as some sort of terrain or the entire point of it is to make the rogue disarm it while a fight is going on or make it a choice to disarm, avoid, or just bull through.
The second situation is where an active check by the party's high Perception spotter will find the hidden thing. This is probably your more normal trap that might show up on its own or as part of an encounter where it is intended to be dealt with while its active (a magic crossbow turret that acts pretty much like a monster that COULD be nerfed if a PC is smart). These types of traps may well be foreshadowed (IE there are skeletons of past victims or blast marks or whatever nearby that clue the PCs in to make an active check). Otherwise they could be on a door or some other area that the PCs normally will check anyway and if they are dumb and don't check the door for traps then they get the booby prize.
The third, rare, situation is something so well hidden it cannot be detected by any means at the party's disposal. A trap of this kind would be rare. It is a fait accompli that the characters will set it off except possibly by sheer luck. It could be used as a plot element of some sort that is meant to be found later by other means. Maybe a secret entrance used by a monster or something that later explains how the monster escaped or entered an otherwise secured area. Some special magic or ritual could later reveal it as part of an expostulation or the party could end up on the other side of the secret door where it is obvious and they suddenly solve a mystery it caused. An unfindable trap could serve a similar purpose or it could be actually deployed BY the PCs as a defensive measure or something.
So the only issue with this whole perception thing is for the DM to understand these three cases and what they are good for and use them creatively in adventures to achieve his goals.
Easily spotted traps can be used to give the PCs hazards to deal with or just for 'flavor' or to show that an area is dangerous. Findable traps are the standard type that punish PCs that don't look for traps. Unfindable ones are plot devices.
Within the findable traps category you might make some that are very difficult to find with an active check and others that are pretty easy but could still be missed. The former type will reward repeated searching but you will need to foreshadow them in order to make it obvious that more searching is a good idea. The later type are there often to let the rogue 'shine'.
Uh huh.
If DMs do not envision the system the way you do, then they do not understand the best way to use the system.
This is just wrong on so many levels.
The problems with 4E Perception are the same problems that have existed for a long time in DND with regard to Spot.
1) The DM creates something hidden. The Passive Perception game mechanic is basically worthless because if it is below that number, the PCs always find it. Why bother? Just tell the PCs that something is there.
2) The concept of foreshadowing is just another way of saying: Roll your Perception. It might be a slightly cooler way, but it boils down to the same thing.
3) The chance to find something hidden is dependent on the DC of it combined with the number of players rolling and their Perception bonuses. If the DM wants the party to have an ~50% chance to find something, that can be blown out of the water if fewer or more PCs actively attempt Perception than the DM expected. In the case of fewer PCs (or none), then it becomes a case of the DM either letting it slide, or throwing out clues, or fudging or whatever. I prefer just letting it slide. If I wanted the PCs to auto-find something, I would just allow them to find it.
So my preferred system is to only use Passive Perception in "within range" situations. In other words, if the PCs with the high Passive Perception get within range (e.g. 6 squares in a given situation or whatever), they auto-spot something. If they don't get within range, they don't. If within range is a long distance, I don't even bother with Passive Perception DCs. I just tell the PCs what the observant PC(s) notice. Passive Perception is a rule and game layer that really isn't needed.
I use Active Perception for everything else. It is either obvious to some or all of the PCs, or you have to roll and you have to tell me you want to roll.
So in the case of a hidden door or a hidden trap, they are typically hidden for a reason. It will almost always be an Active Perception required to spot them.
In the case of a hidden trap that is not intentionally made to be a trap (like a dead fall outdoors due to a natural sinkhole or something), then it often becomes a Passive Perception (or Active Perception if the player wants to) based on "within range". The DC is typically not high for these situations, so they fall under the Passive Perception result of the most observant PCs. But, that does not mean that they auto-spot it. They only auto-spot it if they get close enough. If a different unobservant PC walks into the area and the observant PCs are not close enough to see it and nobody either tries to make an Active Perception or fail their rolls, then the unobservant PC walks into the trap.
Another way of handling this is to make the Perception DC a set number and then increase it by 2 for every square away from the hidden object. That way, the DM knows ahead of time exactly how close each PC has to get in order to make a Passive Perception automatically.
So in response to the OP, I never tell my players to roll Perception and I rarely have hidden traps or other things which a Passive Perception will make unless I also want an Active Perception from the less observant PCs to have a fair chance of finding it.
Hidden things should be hidden. They should rarely be auto-found. The DC for hidden things should often be higher (and somethings a lot higher) than the best Passive Perceptions in the party. If they are not higher, then they should be ranged based Perceptions.
Otherwise, why bother? Just tell the group that they spot the trap if it is easy to spot.
AbdulAlhazred
Legend
KD, I think you're making it too hard. Like I say, there are a few different reasons for something to be 'hidden' and not all of them require that it be hard to find something.
A trap could be something that is just supposed to be totally obvious and needs no perception to spot, that's fine.
It could be cinematic to make it 'hidden' but not really hidden from the characters, so it has a low DC to spot, which is fine too, its the same as something that isn't hidden except thematically you are telling the players that they have found something 'hidden' and thus it is an atmosphere thing or maybe a plot device to explain why some NPC didn't find it at some point or make the story work around why nobody else has spotted this thing before. The PCs are just that good that they 'find' the thing when others didn't.
It could be a trap you only want the higher perception character(s) to spot automatically, in which case the DC would be in a range where someone well trained in perception will spot it automatically but most untrained characters won't. This could well be your case where the outcome depends on who goes where. Its primarily designed to let the high perception character shine and give him an advantage that he has earned vs the lower perception people.
It could be something well hidden that needs an active check. Like I said before you want either foreshadowing or to have the trap on some point that the PCs will normally check or else you might as well just make it unfindable and unavoidable and rack up some damage on them. Again this will probably let the high perception character shine, but depending on exactly what the DC is its probable that other PCs will have SOME chance to find the thing. Personally I find this type of trap to be the least useful because you are just relying to some extent on luck. Hey, you got a crummy roll on that check, well too bad you're now taking X damage... It CAN be exciting if the effects of the trap are not too severe or the trap just redirects the PCs (like maybe its a slide or something and if they trigger it they just go to a different area or something).
The unfindable case is again as I said before primarily a plot device. Its a perfectly legitimate setup but I would never use it with a damaging trap that the PCs will run into as again its just some auto-damage, so why bother? At best it could be some kind of element of a combat encounter that is really essentially a hazard, but in that case it seems boring to have it unfindable. The PCs should at least have a CHANCE to know the full tactical situation they are entering.
Since the existing perception skill mechanics seem to adequately support all these possibilities I'm not real sure what the issue is.
As far as conditions and modifiers for spotting things you will note that traps themselves always specify this kind of thing. They will say that a DC is X for an adjacent character to spot the trigger plate or whatever. There is a general rule for distance and perception penalties but it is pretty mild (-2 per 10 squares I think). Its perfectly normal to have more rigid requirements for specific things and that was obviously considered when the system was written as evidenced by the way traps are written up.
So yeah, I still don't see the mechanical problem. I can see where the system requires the DM to think about how to use it, but I guess I don't really see where that is a flaw in the system or that it really has much to do with what mechanics you use. Any way you slice it the DM needs to think about how he's designing his adventure. There's no free lunch with any system. I mean if you think about the old style thief mechanics from say 1e its all basically the same. There was a probability to find a trap. The same possibilities existed then as now. The current system just has a better mechanics where you can have passive detection IF you want it. If you don't want it, then set the DC accordingly.
A trap could be something that is just supposed to be totally obvious and needs no perception to spot, that's fine.
It could be cinematic to make it 'hidden' but not really hidden from the characters, so it has a low DC to spot, which is fine too, its the same as something that isn't hidden except thematically you are telling the players that they have found something 'hidden' and thus it is an atmosphere thing or maybe a plot device to explain why some NPC didn't find it at some point or make the story work around why nobody else has spotted this thing before. The PCs are just that good that they 'find' the thing when others didn't.
It could be a trap you only want the higher perception character(s) to spot automatically, in which case the DC would be in a range where someone well trained in perception will spot it automatically but most untrained characters won't. This could well be your case where the outcome depends on who goes where. Its primarily designed to let the high perception character shine and give him an advantage that he has earned vs the lower perception people.
It could be something well hidden that needs an active check. Like I said before you want either foreshadowing or to have the trap on some point that the PCs will normally check or else you might as well just make it unfindable and unavoidable and rack up some damage on them. Again this will probably let the high perception character shine, but depending on exactly what the DC is its probable that other PCs will have SOME chance to find the thing. Personally I find this type of trap to be the least useful because you are just relying to some extent on luck. Hey, you got a crummy roll on that check, well too bad you're now taking X damage... It CAN be exciting if the effects of the trap are not too severe or the trap just redirects the PCs (like maybe its a slide or something and if they trigger it they just go to a different area or something).
The unfindable case is again as I said before primarily a plot device. Its a perfectly legitimate setup but I would never use it with a damaging trap that the PCs will run into as again its just some auto-damage, so why bother? At best it could be some kind of element of a combat encounter that is really essentially a hazard, but in that case it seems boring to have it unfindable. The PCs should at least have a CHANCE to know the full tactical situation they are entering.
Since the existing perception skill mechanics seem to adequately support all these possibilities I'm not real sure what the issue is.
As far as conditions and modifiers for spotting things you will note that traps themselves always specify this kind of thing. They will say that a DC is X for an adjacent character to spot the trigger plate or whatever. There is a general rule for distance and perception penalties but it is pretty mild (-2 per 10 squares I think). Its perfectly normal to have more rigid requirements for specific things and that was obviously considered when the system was written as evidenced by the way traps are written up.
So yeah, I still don't see the mechanical problem. I can see where the system requires the DM to think about how to use it, but I guess I don't really see where that is a flaw in the system or that it really has much to do with what mechanics you use. Any way you slice it the DM needs to think about how he's designing his adventure. There's no free lunch with any system. I mean if you think about the old style thief mechanics from say 1e its all basically the same. There was a probability to find a trap. The same possibilities existed then as now. The current system just has a better mechanics where you can have passive detection IF you want it. If you don't want it, then set the DC accordingly.
chitzk0i
Explorer
I would have the DC vary from one pressure plate to another. Maybe the PCs find a broken one with their passive perception or they see some other clue that will tip them off and get them to make active rolls. Have most require a roll of 12-14 from their best perception, but some require a 15+. Also, you want the PCs to actually move into the hallway, so make sure to enforce the -1 per 10 feet on perception checks.
++Mentat. If you want some variation, just have the trap roll to hide from the PCs rather than the other way around. The purpose of passive perception is, largely, to act as a defense -- so we can have one roll for everything rather than a bunch of little rolls.
Re static DCs against passive in a mod--agreed that this can be fine in a pre-made mod, as it just means that a party with good perception gets to avoid one of the hazards.
Re static DCs against passive in a mod--agreed that this can be fine in a pre-made mod, as it just means that a party with good perception gets to avoid one of the hazards.
Not hard. Different.
Your first two examples here are the same thing. There is no need for a Passive Perception rule for these. The DM just describes the obvious stuff in whatever manner the DM wants to for plot, cinematic, or whatever other reasons.
The problem with this approach is that the higher perception characters always spot the hidden thing. There is no mystery. There is no chance for the lower perception PCs to accidently fall in the trap or step on the pressure panel.
As a general rule, I've never like auto-successes where there is no active attempt. For example, auto-success on a climb? Fine. The player is actively deciding to climb. Auto-success on a perception? Not so cool. Especially when we are talking about something like a hidden trap. The "in game" designer of the trap went out of his way to make it hidden, but the DM allows an auto-success. That just doesn't sit well with me.
If a DM said "Oh yeah, the Elf spots a trap across the room" when the PCs walk in a room, I would wonder "Who designed that trap? Barney Fife???".
So a solution where the auto-success is based on proximity gives two possible chances to find it: the perceptive PC gets close enough, or any PC tries Perception and makes the roll. It gives one a real REASON for having the Passive Perception rule at all in the first place.
As for active checks, remember, Perception is now a Minor Action. Even a low Perception PC can sometimes afford a minor action in a given round and get lucky.
Not that all players will do this, but the option is available.
This I think is the real intent of Perception. Find something that is hidden. But, I think foreshadowing has to be done really carefully or the DM might as well just say "Roll Perception".
Actually, auto-damage is one of the few reasons for the unfindable case. The unfindable hidden trap outside the findable hidden vault that not only auto-damages the PCs, but also makes them wonder why a trap is just sitting in the middle of a corridor somewhere.
But there aren't many good reasons for the DC being so high that the PCs cannot find something hidden. Like you say, why bother?
The vast majority of DCs that the DM introduces in the game system should be ones reachable by at least one PC in the party unless it is something special like a slippery cliff that the PCs should be climbing in 10 levels, not today.
The issue is that Passive Perception is auto-success and a waste for case #1, auto-success for some PCs in case #2, and not useable in case #3.
For all intents and purposes, Passive Perception if used as written is a totally worthless rule. I just add the proximity element to make it worthwhile again.
Guess we'll just have to disagree here.
Nytmare
David Jose
My understanding of Passive Checks were that they were simply a shorthand for taking 10 while doing something else. Taking a look at the averages for an indistinct stretch of time is a heck of a lot easier than breaking the entire thing down to 3 action rounds.
As such, I always assumed that they should kinda stop happening when you zoomed in to the granular, round by round slugfest of the battlemat. They make sense as a DC, but not for filling in for an active action.
Deciding to "take 10" on the battlemat should mean that you are spending 10 standard actions rolling a d20, no?
[EDIT] Otherwise, wouldn't you treat every d20 roll as bottoming out at 10 since you could use your passive action as a crutch?
As such, I always assumed that they should kinda stop happening when you zoomed in to the granular, round by round slugfest of the battlemat. They make sense as a DC, but not for filling in for an active action.
Deciding to "take 10" on the battlemat should mean that you are spending 10 standard actions rolling a d20, no?
[EDIT] Otherwise, wouldn't you treat every d20 roll as bottoming out at 10 since you could use your passive action as a crutch?
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Prism
Explorer
Perception can take a standard action or one minute to do. If its something that can be noticed with a standard action like a hidden monster I apply passive perception. If its something hidden like a secret door that would normally take 1 minute to search for I don't allow a passive perception - I might if they stood right by it for a minute or so, or rested in the room. For traps I mix and match them depending. Sometimes I allow a clue with a passive roll and then maybe require a full active search roll taking a minute to find the lever that disarms it or secret door that bypasses it. Other times I won't. If the rogue doesn't actively search for traps on a locked chest I'm not usually going to hold their hand and let them notice it with a passive check
No, thats taking 20 (taking 20 standard actions rolling a d20, with no failure result). Taking 10 means you're taking a slightly worse than average result in an unstressed situation in one action.
But passive perception, while it derives from that, is actually somewhat different, as I mention upthread--the real reason it exists at all is so you don't have to roll two opposed d20s when the probability of success if you just roll one d20 for the "attack" is more or less equivalent. The fact that stealth rolls actively against passive perception, and similarly for bluff vs passive insight makes those skills more reliable while keeping the overall 2 person reliability the same.
The problem, of course, comes when you then try to use passive perception/insight to solve the age-old question if "how do you handle someone's character not noticing something without the player knowing it". (not to mention "how do we stop a game from turning into "take 5 steps, make a perception roll" snoozefest"). The -best- solution to that problem is to make it an active check and have good enough players that they don't metagame it (thus letting them spend encounter-level or daily level resources to boost the check if they want--at a cost of denying the players clue-based retries as they either succeed or fail).
Failing that, KD's solution of circumstance bonuses based on player actions is actually pretty good; it rewards good play (and playing to a character's strengths) rather than good die rolling; one can enhance it by having different decriptions depending on the highest passive perception--no perception lets you get all the info, but the better your perception is, the better a clue you get that there's something to see here.
