Passive Perception weirdness and Observant feat - how to handle it.

[Threeshades]

So i've seen some discussion previously on how passive perception is supposed to work, especially with the observant feat around. So I wanted to open this can of worms here once again and give my idea how to handle it in a way that makes sense:

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Reading the PHB, it seems like the idea is, if a character is not actively looking for something or someone, the DM is supposed to compare the Perception DC to the character's Passive Perception. If the character does actively look, he or she makes a Perception check.

Now this is already strange because that would mean a character with, say, a +3 Perception (and consequently 13 passive) who is not actively looking for something is 100% assured to find anything hidden with a DC of 12 or less. Now if the same character is actively trying to find it, he has a good chance of missing the thing, because the roll could come out below the DC.

This only becomes wierder with the observant feat, which adds +5 to the creature's Passive Perception and nothing to active rolls.

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So eventually I came to the conclusion that the only way to really make sense of this is if you always apply Passive Perception AND on top of that a creature can make a roll if it is actively looking out.

For example: our +3 Perception character is exploring a dungeon expecting traps, so the player makes active perception checks. He comes across a trap that is hidden with a DC 10 and rolls a 3 on the d20 (+3=6), the active check wasn't enough but because the passive is also in effect he finds the rather shoddily hidden trap. Later he comes across a DC 18 trap, his passive is not enough to spot the trap, so he better hope he rolls a 15 (+3=18) or better on the d20 if he is still looking for traps. If he has stopped actively searching for traps, he will not get a check and automatically miss this one.

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This is how I have come to handle Passive Perception and active checks. It does mean that anything hidden with a DC 9 or less is basically obvious to anyone who isn't distracted or somehow impaired (disadvantage reduces passive by 5) or fairly oblivious in general (due to a negative Wisdom mod and no proficiency in Perception)

How do you do it? Do you think my way of doing it is correct? Or did I just state what was already obvious to you?

[Garbage-Tier Waifu]

So, I haven't ever had Observant in MY game, but I've used it. Eventually I just started asking my DM if my PP of 21 or Investigation of 23 was able to find the hidden thing, and he just would sigh and nod. It did take most of the surprise out of some of the sessions, but that's sort of what diviners do ;)

That said, yeah, passive perception can be used that way and it does mean you can throw in easily missed details for the highly observant characters who invested into that sort of things to spot. Passive perception is more important for determining if a creature notices another creature in Stealth, but it also works for details. But it also can mean that traps become fairly pointless most of the time. Perception checks is only important for actively looking, and every creature is entitled to passive perception to see if they are alerted to environmental information even without being prompted.

[Threeshades]

Okay so maybe thereshould be an additional qualifier. Some things may be hidden in such a way that they cannot be found without actively searching.

A key that is placed inside a closed desk drawer won't be found by someone with a passive Perception of 30, if that person just passes through the room even if its DC is just 10. Someone who says "I search the desk" gets to roll, and only the roll will decide if they find it.

Similarly a traps mechanisms might be concealed and/or camouflaged well enough that they are indistinguishable from the harnless surroundings.

[Kalshane]

I generally set the Passive Perception as the minimum for someone who is actively searching (since, as you say, it seems silly that they have a chance of being less observant when they're actively looking for something.) This doesn't bother me so much with traps, since all Perception does is clue you in to something being out of the ordinary. Investigation is required to actually recognize the trap and what it does. (And even there, depending on the trap, there might be more involved than a simple Thieves' Tools check.)

However, if someone is distracted or otherwise has their attention focused on something other than their surroundings, their Passive Perception doesn't come into play and they just get a roll (possibly with disadvantage, depending on how distracted they are.)

[Drejk]

I think the key information is hidden in adventuring section (activity while adventuring, I think): passive Perception main role is noticing threats and setting DC for stealth checks of hidden creatures. It's not the same as finding hidden objects and passages just because you passed them.

Also, passive checks are used for repeated task:

Basic Rules wrote:

A  passive  check  is  a  special  kind  of  ability  check  that

doesn’t  involve  any  die  rolls.  Such  a  check  can
represent  the  average  result  for  a  task  done
repeatedly,  such  as  searching  for  secret  doors  over
and  over  again,  or  can  be  used  when  the  GM  wants
to  secretly  determine  whether  the  characters
succeed  at  something  without  rolling  dice,  such  as
noticing  a  hidden  monster.

[Dustin Ashe]

This is one of those rules that should serve the DM or should be ignored.

In one of my campaigns, I almost never use passive Perception. In mt other campaign, I use it almost exclusively. Different campaigns have different needs.