Observant, Passive Investigation, and Illusions

[Crake]

If I have the observant feat, granting me a passive investigation of say, 20, does this mean that any illusion that allows for an investigation check to notice will be done so passively without an action on my behalf? If so, does that essentially make Observant the best anti-illusion feat ever?

[Demonic Spoon]

There aren't any rules that I'm aware of outside of passive perception vs stealth that explicitly call for the use of passive checks. All passive checks aside from stealth that I am aware of are raw DM fiat. In related news, I hate the Observant feat.

[DanyBallon]

... In related news, I hate the Observant feat.

Observant is wonderful for my low wisdom lore bard. He's somehow able to notice the fine crack in the wall deducing that there's a hidden door, even guessing perfectly how to open it, but will definitely believe anyone telling him that's the gate to hell :P

[Louro]

I am DMing right now.
I hate that ffffeat.
I love illusions.

You can only attempt to disbelief an illusion if:
1) It makes no sense (It's raining doughnuts!)
2*) You make contact (Nice hat, let me touch it)
3) You actively use your action to carefully examine it.

So, passive perception won't do the trick.
*With some illusions I use the "real belief" variant, making them "real" for those who don't pass the save roll. Even if the hat is an illusion you believe it is in your hands if you fail the save.
By rules you automatically disbelief if you touch it.

[Quarterling]

So, passive perception won't do the trick.
*With some illusions I use the "real belief" variant, making them "real" for those who don't pass the save roll. Even if the hat is an illusion you believe it is in your hands if you fail the save.
By rules you automatically disbelief if you touch it.

As a DM I follow similarly in regard to illusions they trick the viewers mind it's not like an outfit with a bit of plaster on the cheek though on a side note observant is probably one of the best feats in the book. It's bonkers good

[Crake]

3) You actively use your action to carefully examine it.

So, passive perception won't do the trick.

It's not about passive perception, its about passive investigation from the observant feat.

[Louro]

It's not about passive perception, its about passive investigation from the observant feat.

Never mind, you need to use your action, so it is not passive. It is active, the players must declare he wants to examine the object and rolls.

[DanyBallon]

Since there is no real description of passive Investigation, it's up to your DM to decide when it should apply. I would allow passive investigation to be used to know how to disarm or bypass a trap. To gather general gossip or remember knowledge that a character might know. I.e in the Age of Worm Adventure Path a character passive Investigation would let them know all the details on the Wind lords up to their passive investigation score. If someone then decide to do more research on the topic, then they would roll but won't get lower result than what they already know. Or if they come by a trap with a low Disable DC then they recall that this kind of trap can by disarm this way. On higher DC they just wont have a clue and will be required to roll to find out how to disarm it.

[Myzz]

Never mind, you need to use your action, so it is not passive. It is active, the players must declare he wants to examine the object and rolls.

RAW says its the DM discretion...

And the point of Observant is that he is actively doing those things... Unless otherwise engaged.

A highly intelligent observant person would know that the shade of green in the illusion doesnt quite match what the surrounding forest's green looks like and would then subconsciously nit pick the illusion... until it unraveled for him...

[Easy_Lee]

Regarding illusions, you have to attempt to disbelieve them in order to disbelieve them, as stated. Disguise yourself as a box and people will see a box unless they specifically try to examine you and see if you're actually a box.

[Laurefindel]

Regarding illusions, you have to attempt to disbelieve them in order to disbelieve them, as stated. Disguise yourself as a box and people will see a box unless they specifically try to examine you and see if you're actually a box.

True, but you could make a case that with the Observant feat boosting your passive perception/investigation so high, you will notice small details that would lead you to doubt the reality of the object, thenceforth actively seeking to disbelieve it as being real.

For example, you could notice that the box casts no shadow, or that dust hasn't accumulated on it as much as on other objects, or that the same wood grain pattern appears on all visible sides of the box.

So while this wouldn't be an auto-spot, it could lead to a disbelief save.

[DanyBallon]

True, but you could make a case that with the Observant feat boosting your passive perception/investigation so high, you will notice small details that would lead you to doubt the reality of the object, thenceforth actively seeking to disbelieve it as being real.

For example, you could notice that the box casts no shadow, or that dust hasn't accumulated on it as much as on other objects, or that the same wood grain pattern appears on all visible sides of the box.

So while this wouldn't be an auto-spot, it could lead to a disbelief save.

This would be a reasonable use of passive perception in my home game. You don't get to notice the illusion per say, but you notice that something is amiss. Thus allowing either an other save vs the illusion or advantage on the check

[Person_Man]

On a related note, there's a nasty trick that I picked up from an old Gygax module years ago. Evil DMs can nest things disguised by other means inside of an illusion. If the players penetrate the illusion by whatever means, they treat whatever they find at face value, assuming that the problem has been solved, and often don't bother to check for traps or take other reasonable precautions.

For example, the players come across a wall that seems out of place. They investigate, and find out that the wall is an illusion hiding a small alcove with an open chest in in. They try to take the treasure inside, but find out that its actually a Mimic. They finally defeat the Mimic and get the treasure inside. Later they find out that one of the magic items they found inside is actually cursed (or a potion labeled Healing is actually Poison, or its all made out of iron and attracts the presence of Rust Monsters in the next part of the cavern, etc).

I don't use such tactics very often. But I do pull them out occasionally, when players get too meta-gamey or stop bothering to pay attention and ask questions about their surroundings.

[Myzz]

This would be a reasonable use of passive perception in my home game. You don't get to notice the illusion per say, but you notice that something is amiss. Thus allowing either an other save vs the illusion or advantage on the check

passive perception you would notice it, but it would have no real meaning (generally aware)...

Passive Investigation you passively compare/contrast (make deductions)...

AND metagame wise if you do use Passive Perception and tell players whats amiss, they are going to then investigate actively...

really comes down to is that a Wis check or an Int check... I would default that its an Int check vs Illusions... but thats not RAW ...

[Easy_Lee]

True, but you could make a case that with the Observant feat boosting your passive perception/investigation so high, you will notice small details that would lead you to doubt the reality of the object, thenceforth actively seeking to disbelieve it as being real.

For example, you could notice that the box casts no shadow, or that dust hasn't accumulated on it as much as on other objects, or that the same wood grain pattern appears on all visible sides of the box.

So while this wouldn't be an auto-spot, it could lead to a disbelief save.

That's something the player should do, not the character. You're getting into the-game-plays-itself territory if you let class features stand in for active players.

DM: the room looks like this and there's a box in it
Bad PC: ...
Good PC: I examine the box
DM: you see that the box casts no shadow

As opposed to:

DM: you see a box in the room but, because you're observant, you notice that The box is probably an illusion without even having to tell me you looked at it.

Players should be playing the game. If they aren't asking questions or looking for clues then they aren't really observant, no matter how observant their character sheets claim they are.

[Laurefindel]

really comes down to is that a Wis check or an Int check... I would default that its an Int check vs Illusions... but thats not RAW ...

No it ain''t

and besides, a passive resistance/check would assume that there was a check to oppose in the first place. By RaW if you don't know how well the illusion has been made, you can't set the bar where passive investigation would spot that something is amiss.

But in 5e D&D, I feel much better, as a DM to move around the RaW to make a better story/adventure/good time with my friends than in previous versions of D&D since 2e A&D (and I include Pathfinder in there). So I wouldn't dismiss that kind of scenario immediatly.

Of course you would have the PC make disbelief before stating the reason that led it to make the save in the first place. Otherwise, telling the player that the object is suspicious is telling the player that "here is an illusion".

[Myzz]

just because someone knows its an illusion does not mean they automatically disbelieve or see through said illusion, so you don't need to know the DC of the illusion cast.

my point was, beware of using passive perception to simulate deductions (investigation).

and as you pointed out, telling PC's that they notice something fishy is infact making a deduction... that what they noticed doesn't belong.

The hard part I've always thought is that characters with low Int scores might not be able to spot the out of place stuff in you flavor text that Players spot due to thier INT.

[DanyBallon]

That's something the player should do, not the character. You're getting into the-game-plays-itself territory if you let class features stand in for active players.

DM: the room looks like this and there's a box in it
Bad PC: ...
Good PC: I examine the box
DM: you see that the box casts no shadow

As opposed to:

DM: you see a box in the room but, because you're observant, you notice that The box is probably an illusion without even having to tell me you looked at it.

Players should be playing the game. If they aren't asking questions or looking for clues then they aren't really observant, no matter how observant their character sheets claim they are.

Instead, this could go this way:
DM: the room looks like this and there's a box in it
DM to the PC with high passive perception: you notice that the box cast no shadow.
PC with high passive perception: I investigate that box
Other PCs: pay attention to something else because the have no reason to suspect that the box is an illusion.

The rogue may find out if looking carefully for traps

[Easy_Lee]

Instead, this could go this way:
DM: the room looks like this and there's a box in it
DM to the PC with high passive perception: you notice that the box cast no shadow.
PC with high passive perception: I investigate that box
Other PCs: pay attention to something else because the have no reason to suspect that the box is an illusion.

The rogue may find out if looking carefully for traps

In other words the DM just told his player what to do. I don't see how that's any different.

[Laurefindel]

my point was, beware of using passive perception to simulate deductions (investigation).

Fair enough.

My only point was to illustrate how a passive perception could sensibly lead to a disbelieve save, rather than a rigid "active search only".

As for avoiding metagaming, you could ask for a save without stating why. For all the player knows, it could be a mind-affecting effect, or some other kind of spell. If the save is successful, you tell the player that he/she has discovered an illusory box, which her Observant feat made possible. Or once the PC declare that they are searching the room for trap and doors and whatnot, allow a save then.

Basically, I would simply acknowledge that Observant (or any high passive perception score) could grant some kind of benefit against illusions in some situations, including (but limited to) allows a free "interaction" when the conditions seem appropriate.

When would I allow that and under what circumstances? I can't tell; I'd rely on my experience as a DM and what type/style/genre of game my group wants to play.

[Louro]

If a DM grants automatically that info to a player... Half of the exploration flavor us lost.

And I feel that the observant feat is already good enough making you almost inmune to ambushes and traps. This is not bad at all, just forces the DM to be a bit more imaginative and evil. But if you add illusions on top of that... too much IMHO.

[DanyBallon]

In other words the DM just told his player what to do. I don't see how that's any different.

You can see it this way, but I prefer to see this, than someone who dumped is mental stat, going around and acting like Sherlock Holmes, because the player metagamed that since there's a box, it should be checked just in case...

It's just different style of play I presume :)

[Louro]

Do you add riddles and puzzles on your adventures?
Do you allow your players to roll INT to solve them?
Metagaming is not always a bad thing.

[SharkForce]

last i checked, illusions already have a mechanic described for detecting them. it is not passive perception/investigation (or active perception/investigation, for that matter).

you could allow it, if you feel that illusions are overpowered for some reason and need nerfing, i suppose. but i wouldn't allow it except as a specific house rule designed to nerf something i considered overpowered. and for me at least, i generally don't find illusions to be overpowered.