Stealth, Perception, and lighting questions

[Segev]

We'd come to what I thought was a good conclusion on this in the commonly misunderstood rules thread, but then I read the Boots of Elvenkind and that opened up the question for me again. It'll take me a bit to explain how, so please bear with me.

First, an example or few.

1. Alice is invisible. Bob enters the brightly lit room where Alice is. Alice has taken the Hide action, knowing he's coming, but, being invisible, hasn't hidden behind anything. Being invisible, she can absolutely hide in plain sight. Does Bob have Disadvantage on his Wisdom(Perception) check (passive or otherwise) to figure out where Alice is / that Alice is present?
2. Alice is invisible. Bob enters the dimly lit room where Alice is. Alice has taken the Hide action, knowing he's coming, but, being invisible, hasn't hidden behind anything. Being invisible, she can absolutely hide in plain sight. Does Bob have Disadvantage on his Wisdom(Perception) check (passive or otherwise) to figure out where Alice is / that Alice is present?
3. Alice is invisible. Bob (who lacks darkvision) enters the dark room where Alice is. Alice has taken the Hide action, knowing he's coming, but, being invisible, hasn't hidden behind anything. Being invisible, she can absolutely hide in plain sight. Does Bob have Disadvantage on his Wisdom(Perception) check (passive or otherwise) to figure out where Alice is / that Alice is present?
4. Alice is perfectly visible. Having heard Bob coming, Alice hides behind a tapestry in the brightly lit room. Does Bob have Disadvantage on his Wisdom(Perception) check (passive or otherwise) to figure out where Alice is / that Alice is present?
5. Alice is perfectly visible. Having heard Bob coming, Alice hides behind a tapestry in the dimly lit room. Does Bob have Disadvantage on his Wisdom(Perception) check (passive or otherwise) to figure out where Alice is / that Alice is present?
6. Alice is perfectly visible. Having heard Bob coming, Alice hides behind a tapestry in the dark room. Does Bob have Disadvantage on his Wisdom(Perception) check (passive or otherwise) to figure out where Alice is / that Alice is present?
7. Alice is invisible and wearing Boots of Elvenkind. Bob enters the brightly lit room where Alice is. Alice has taken the Hide action, knowing he's coming, but, being invisible, hasn't hidden behind anything. Does Bob have Disadvantage on his Wisdom(Perception) check (passive or otherwise) to figure out where Alice is / that Alice is present?
8. Alice is invisible and wearing Boots of Elvenkind. Bob enters the dimly lit room where Alice is. Alice has taken the Hide action, knowing he's coming, but, being invisible, hasn't hidden behind anything. Does Bob have Disadvantage on his Wisdom(Perception) check (passive or otherwise) to figure out where Alice is / that Alice is present?
9. Alice is invisible and wearing Boots of Elvenkind. Bob enters the dark room where Alice is. Alice has taken the Hide action, knowing he's coming, but, being invisible, hasn't hidden behind anything. Does Bob have Disadvantage on his Wisdom(Perception) check (passive or otherwise) to figure out where Alice is / that Alice is present?
10. Alice is perfectly visible and wearing Boots of Elvenkind. Having heard Bob coming, Alice hides behind a tapestry in the brightly lit room. Does Bob have Disadvantage on his Wisdom(Perception) check (passive or otherwise) to figure out where Alice is / that Alice is present?
11. Alice is perfectly visible and wearing Boots of Elvenkind. Having heard Bob coming, Alice hides behind a tapestry in the dimly lit room. Does Bob have Disadvantage on his Wisdom(Perception) check (passive or otherwise) to figure out where Alice is / that Alice is present?
12. Alice is perfectly visible and wearing Boots of Elvenkind. Having heard Bob coming, Alice hides behind a tapestry in the dark room. Does Bob have Disadvantage on his Wisdom(Perception) check (passive or otherwise) to figure out where Alice is / that Alice is present?
13. Alice is invisible and in a zone of magical silence. Bob enters the brightly lit room where Alice is. Alice has taken the Hide action, knowing he's coming, but, being invisible, hasn't hidden behind anything. Does Bob have Disadvantage on his Wisdom(Perception) check (passive or otherwise) to figure out where Alice is / that Alice is present?
14. Alice is invisible and in a zone of magical silence. Bob enters the dimly lit room where Alice is. Alice has taken the Hide action, knowing he's coming, but, being invisible, hasn't hidden behind anything. Does Bob have Disadvantage on his Wisdom(Perception) check (passive or otherwise) to figure out where Alice is / that Alice is present?
15. Alice is invisible and in a zone of magical silence. Bob enters the dark room where Alice is. Alice has taken the Hide action, knowing he's coming, but, being invisible, hasn't hidden behind anything. Does Bob have Disadvantage on his Wisdom(Perception) check (passive or otherwise) to figure out where Alice is / that Alice is present?
16. Alice is perfectly visible and in a zone of magical silence. Having heard Bob coming, Alice hides behind a tapestry in the brightly lit room. Does Bob have Disadvantage on his Wisdom(Perception) check (passive or otherwise) to figure out where Alice is / that Alice is present?
17. Alice is perfectly visible and in a zone of magical silence. Having heard Bob coming, Alice hides behind a tapestry in the dimly lit room. Does Bob have Disadvantage on his Wisdom(Perception) check (passive or otherwise) to figure out where Alice is / that Alice is present?
18. Alice is perfectly visible and in a zone of magical silence. Having heard Bob coming, Alice hides behind a tapestry in the dark room. Does Bob have Disadvantage on his Wisdom(Perception) check (passive or otherwise) to figure out where Alice is / that Alice is present?

It is noteworthy that while we initially discussed this in the other thread as Boots of Elvenkind making you move silently, they technically only give you Advantage on stealth rolls that rely on moving quietly. Would they apply to all cases, here, where the boots are present? Or only to those where Alice is invisible or in the dark?

Of particular concern, here, is whether Bob gets disadvantage EVER based on the dim lighting, and, if he does, if it goes away if Alice is invisible. The second case would mean that it's possible to make it harder to hide by turning invisible, which seems...counter-intuitive.

[JackPhoenix]

Assuming only sight and hearing in play, as humans don't have that good sense of smell. The boots don't matter for the question, as they influence Alice's Stealth check, not Bob's Perception check.

1. no
2. no
3. no
4. no
5. no
6. no
7. no
8.no
9. no
10. no
11. no
12. no
13. No. She can't be found at all by either sight or hearing, assuming there aren't circumstances that would allow Bob to visually detect her presence and location indirectly (tracks on the floor, for example). If there are, still no.
14. No. She can't be found at all by either sight or hearing, assuming there aren't circumstances that would allow Bob to visually detect her presence and location indirectly (tracks on the floor, for example). If there are, yes.
15. No. She can't be found at all by either sight or hearing.
16. Depends. Is the tapestry set in a way that would allow Bob to find Alice by sight? If it is, no, if it's not, she can't be found either by sight or hearing.
17. Depends. Is the tapestry set in a way that would allow Bob to find Alice by sight? If it is, yes, if it's not, she can't be found either by sight or hearing.
18. No. She can't be found at all by either sight or hearing.

We've been over this. At no point will dim light make finding someone harder than being invisible will, unless you have indirect ways (tracks, movement of surroundings caused by their presence, smoke/rain/water being displaced by their presence...) to detect their presence by sight, at which point the invisibility doesn't matter, as you aren't looking for the invisible person itself (which you can't, anyway).

The disadvantage for dim light still applies in non-Stealth-related situations.

[Greywander]

Dim light (or darkness, for those with Darkvision) imposed disadvantage on sight based ability checks. Being invisible or in darkness (against non-Darkvision races) makes you entirely undetectable by sight. The problem is, it's not really clear which senses a character is able to use when detecting others. It seems to be fairly standard that you can use hearing to detect invisible creatures who aren't hidden, but logically you could just as easily detect a hidden creature (invisible or not) by hearing as well. The Perception check to find a hidden creature is partially based on sight, but also on hearing, so would it have disadvantage if done in a dimly lit room?

It makes sense to me that a normal Perception check represents using all of your senses as best you can, in this case using both sight and hearing to search for a hidden creature. If for some reason one of your senses is impaired, it makes sense that there would be a penalty to the roll since you're relying on fewer senses. However, not all Perception checks are created equal. If someone is stomping loudly down the hall, you don't need sight to tell you that someone is coming. Likewise, if someone is standing out in the open on a bright day, they might be completely silent and it won't stop you from spotting them.

Oh, and let's make it more complicated. We can also find things by touch. So even if you're invisible and in a zone of magical silence, I can still bump into you. Barring powerful magic, there's no way to become 100% undetectable.

So, would the check have disadvantage? I actually don't know. It feels like it should have some kind of penalty. But maybe for stealth it's just a matter of avoiding automatic detection. If not invisible, and you're not hiding behind something, and the area is brightly lit, you should be automatically detected if someone looks your way. To avoid automatic detection, you need to either be invisible, hiding behind cover, or in a dimly lit area (or darkness).

[Tanarii]

Start with: Can BoB Hear or possibly hear Alice? If so are there any modifiers to the check?

Then ask if Bob can see Alice? If so are there any modifiers to the check.

Now compare the two and take the worst set of modifiers, most likely to be detected. That's your check.

[Asisreo1]

I think that it depends on what the creature in question is relying on. In a situation where a creature is moving and in dim light but is trying to stay hidden, the creature they're hiding from would be relying on both sight and hearing and smell.
The lightly obscured area gives disadvantage on perception checks that rely on sight. It doesn't say perception checks that only rely on sight. And doesn't that feel right. At least, in some ways it makes sense that someone hiding would want to stick to the shadows and gain some benefit whether or not they're moving. If they make noise, it can be chalked up to them rolling low on the stealth.

Now, imagine that person is invisible. Do the other creature get disadvantage? Well, they're now heavily obscured which means the unsuspecting creature is now blind to the stalker. However, blind comes with an interesting phrase: A blinded creature can't see and automatically fails any ability check that requires sight. Note: requires. That means that blinded has no effect on passive perception, since it doesn't require sight.
It's a bit unintuitive, isn't it? But check the description of invisible. It notes that creatures can still be heard or leave tracks. That second one's important because it leaves an intuitive understanding of why being invisible doesn't automatically give the victim disadvantage: they can see foot tracts. But what if that creature's in dim light? Then they get the disadvantage. There is nothing saying a creature can't be both lightly and heavily obscured.

There's a bit of a funk going on, though. I'm saying that being in pure darkness gives the victim a higher perception than being in dim light? That seems wrong, though. Well, that's not exactly the case. If the stalker's not moving and holding your breath, the victim is no longer relying on hearing. If the stalker doesn't smell significantly different from its environment, the victim is no longer relying on smell. The stalker isn't touching or being tasted by the victim so victim is now requiring sight to spot the stalker. (This is why being still is stealthier than being on the move.)
But I hear ya, you're not satisfied because moving in dim light is still better than moving in darkness despite how obviously wrong that it. Well, one way to solve that is by having passive Perception *require* sight. It's not too off the mark, unless someone's being much louder than they should be, people usually don't notice subtle noises unless it's extremely quiet. That's not often in an adevnturer's life, though since they have to communicate with their fellow adventurers or are in a loud tavern or doing something else. Smell is one of the last things anyone passively senses unless it's a strong odor. Now, if they have keen hearing or smell, they might still get advantage since they'd certainly not rely on sight more than their keen senses even in a casual state.

That's my take on it anyways.

[Spiritchaser]

Obviously DM and campaign dependent here, however:

Bob is a PC race yes? Not a pet wolf or something?

How big is the room and what is the background noise like?

(Probably lots of similar considerations too, but I find hearing sensory range comes up a LOT)

Range is (or should be) a factor in determining dissadvantage, and it’s usually a shorter range for hearing than vision.
Hearing range decreases even further with background noise.

Obviously not detrimental in a small quiet room or dead silent cave, but...

[da newt]

Logically for me, it depends if the hider is moving. If they are still, I don't think hearing comes into play (I'm assuming breathing is quieter than background noise - aka the rest of the party, etc).

A normal PC can't smell much, so unless there is a reason the hider smells, that doesn't come into play.

Does the seeker say they actively search the room - moving about touching everything? Then they are making plenty of noise themselves, but they could touch ...

Otherwise, perception for people is 90% sight, and I assign DISADV based on that sense mostly.

[Spiritchaser]

Logically for me, it depends if the hider is moving. If they are still, I don't think hearing comes into play (I'm assuming breathing is quieter than background noise - aka the rest of the party, etc).

A normal PC can't smell much, so unless there is a reason the hider smells, that doesn't come into play.

Does the seeker say they actively search the room - moving about touching everything? Then they are making plenty of noise themselves, but they could touch ...

Otherwise, perception for people is 90% sight, and I assign DISADV based on that sense mostly.

DM discretion of course, but I don’t assign a still target an impossible to find status for hearing checks unless they were far away, but I’d be very quick to throw out dissadvantage.

I agree, sight is the greater portion of human perception. Being invisible won’t by definition give an enemy dissadvantage to perceive you, but with the movement players have, at the ranges this game operates at, it functionally will a lot of the time.

This falls into DM judgement, because there is no rule, but an important point to consider is how much background noise is required for a hearing-only check to have dissadvantage at 30’

It isn’t campaign defining but it is pretty important.

[RSP]

Being invisible isn’t an auto fail on sight-involved perception checks, per the RAW:

“An invisible creature can’t be seen, so it can always try to hide. Signs of its passage might still be noticed, however, and it still has to stay quiet.”

So any instance of invisibility can still be noticed via signs of passage, and in dim light conditions, Bob will have Disadvantage on perception checks. As the RAW states, being invisible only allows someone to “try” to hide.

The BoE take away noticing footstep sounds, but “signs of passage” can still be noticed, as can say, the sounds of breathing or the sound made when bumping into something. The boots do grant Advantage to moving silently checks though.

So, mechanically, BoE grant Advantage to Stealth checks if moving silently is involved. Dim Light grants Disadvantage on Perception checks to notice when sight is involved.

[Chronic]

Passive perception Is a an ability check, albeit a special one, and disadvantage grant a malus of 5 to a passive check. So it does have an effect. When blinded, you fail automatically every check requiring sight, so if you don't have a special sense, no passive perception.

[Segev]

Passive perception Is a an ability check, albeit a special one, and disadvantage grant a malus of 5 to a passive check. So it does have an effect. When blinded, you fail automatically every check requiring sight, so if you don't have a special sense, no passive perception.

Except that darkness/blindness should not negate all sound, so shouldn’t you still get a perception check against anybody trying to hide in the dark? The trouble being that now it’s not in dim light and not relying at all on vision; does it suffer disadvantage?

If not, it’s easier to perceive somebody hiding in the dark than in dim light.

Unless you let the perception based on hearing auto fail. Or grant disadvantage despite vision not applying. It’s...weird.

[Tanarii]

Except that darkness/blindness should not negate all sound, so shouldn’t you still get a perception check against anybody trying to hide in the dark? The trouble being that now it’s not in dim light and not relying at all on vision; does it suffer disadvantage?

If not, it’s easier to perceive somebody hiding in the dark than in dim light.

Unless you let the perception based on hearing auto fail. Or grant disadvantage despite vision not applying. It’s...weird.

If you were relying on hearing in the first place, you didn't get disadvantage in Dim Light anyway. Its not a hard concept.

The only problem is DMs that allow people to rely on hearing to oppose Stealth checks at 100ft or more. Edit: Or autolocate non-hiding targets by hearing at similarly extreme ranges.

[Telok]

In my experience what happens in actual play is a ruling that ignores all the nuances.

The stealth, vision, and other bits are spread over 3 to 5 places in the books. The DM hasn't exhaustively read or memorized them and doesn't haunt forums where they're discussed. There aren't examples or specific advice in the rule books.

Therefore the DM rules that A is hidden, or calls for opposed stealth & exception checks, or if B is a PC and doesn't specifically say they're looking for invisible/hidden people then A is hidden.

Light, dark, invisible, etc., just never seems to matter.

[Greywander]

I feel like a lot of this could be solved if hearing (and probably other senses, like smell) was treated similarly to darkvision. Say, something like within 60 feet you can accurately determine the location of non-hidden creatures using just your hearing, and can use hearing for perception checks to find hidden creatures. Beyond that range, it's all sight-based perception checks.

[Asisreo1]

Blindsight...Oh! Blindsight!

Okay, the first sentence of blindsight is: A creature with blind sight can perceive its surroundings without relying on sight, within a specific radius.

Does that mean that a creature without blind sight cannot perceive it's surrounding without relying on sight? That makes sense to me, at least.

[Greywander]

My assumption was that blindsight and tremorsense served as a substitute for sight. For example, spells the require you to see the target. A creature with, for example, echolocation has good enough hearing that it can completely replace vision. Creatures without these senses still have normal hearing, it's just that a creature with blindsight can perceive as good as if they could see the thing in their blindsight range. You can detect someone via hearing, but you need to actually see them to get the details on who/what they are.

Blindsight itself is a bit frustrating, since it doesn't describe how it works or what it can do. A creature with blindsight can read, for example, because the assumption is that it's a type of "sight" and nothing says they can't. But there would certainly be cases where it wouldn't make sense for them to read via blindsight, such as those using echolocation.

[Asisreo1]

My assumption was that blindsight and tremorsense served as a substitute for sight. For example, spells the require you to see the target. A creature with, for example, echolocation has good enough hearing that it can completely replace vision. Creatures without these senses still have normal hearing, it's just that a creature with blindsight can perceive as good as if they could see the thing in their blindsight range. You can detect someone via hearing, but you need to actually see them to get the details on who/what they are.

Blindsight itself is a bit frustrating, since it doesn't describe how it works or what it can do. A creature with blindsight can read, for example, because the assumption is that it's a type of "sight" and nothing says they can't. But there would certainly be cases where it wouldn't make sense for them to read via blindsight, such as those using echolocation.

Well, I think the case where a blindsight creature needs to read is rare but I assume that if it comes up, they can magically read. Though, you can tell if a creature is using echolocation or some other weird variant on their senses by looking at their features. What isn't there, isn't there.