D&D 5E Passively Perceiving in Dim Light

[Flamestrike]

You have to be clearly seen. What that means is up to the DM.

Dim light (or other light obscurement) doesnt fulfil that criterion for hiding in and of itself.

Otherwise the first bullet point of the Skulker feat and the Wood Elves racial ability are obsolete.

Barring those abilities (or similar) I wouldnt rule someone able to Hide in dim light alone, and Im pretty sure the rules dont support it either.

 

[Flamestrike]

Keep in mind, disadvantage on Perception is also relevant for the purposes of detecting traps and secret doors and and such. PCs are less likely to succeed in these activities in dim light.

Yep. Pit traps dont make noise, so they're getting the -5 to spot while in darkvision range. Likely other traps too.

 

[Shiroiken]

Against creatures, I don't automatically apply the -5 if isn't a large amount of noise going on (such as during a combat), but decide based on the situation. Non-living hazards (including a lot of undead an constructs in addition to traps) will always suffer the -5, since vision is pretty much the only way you'll know.

 

[Asisreo]

Dim light (or other light obscurement) doesnt fulfil that criterion for hiding in and of itself.

Otherwise the first bullet point of the Skulker feat and the Wood Elves racial ability are obsolete.

Barring those abilities (or similar) I wouldnt rule someone able to Hide in dim light alone, and Im pretty sure the rules dont support it either.

It's not necessarily that they're hiding in an open field. They're behind, say, a crate. They might have a body part poking out, though. Or, even more confusing, they might be breathing too loudly.

 

[jgsugden]

In a lightly obscured area, such as dim light, patchy fog, or moderate foliage, creatures have disadvantage on Wisdom (Perception) checks that rely on sight.

If the perception check relies upon sight, then it is at disadvantage.

Relies is not a defined term in D&D. Common usage means that it must be dependent, not just utilized. As such, if you could not perceive the thing without seeing it, then the penalty applies. If you could notice it due to sounds it makes (or via other senses) the penalty does not apply.

So, a creature using darkvision in dim light:

* Tries to spot a creature that is hidden. The creature is stationary, and isn't making any obvious noises. I would rule that the only sense that could detect the creature is sight, so the perception check is reliant upon the sight, and thus the -5 penalty applies.

* Tries to spot a creature that is hiding. The creature has been slowly moving up to do a sneak attack on the observing creature. Because they are moving around, the observer has a chance to hear their movement and there is no penalty to the perception check.

* Tries to spot a defect in a tapesty. If they use their hands as well as their eyes, no penalty. If they use only their eyes - penalty.

* Tries to hear something. No penalty.

* Says they want to look around in a cave. I'd look at what is there to be found and determine what it would take for the PC to be using a sense other than sight to find it. Then I'd ask them to describe how they are looking around and would either apply the penalty or not based upon whether they are relying upon sight, or are using a different sense in a way that would assist.

 

[GMMichael]

We can all agree darkvision isn't a perfect mode of vision since PC's can only see in dim light and therefore have disadvantage in perception checks that rely on sight. My problem is that I don't know if passive Perception relies on sight and takes the -5. I mean, hearing ability hasn't been disabled, so what's the deal?

Well, "passive" implies that you're not trying very hard. So yeah, disadvantage.

However, in the dark, it seems that the ears take up the burden of the eyes, so there's no net loss of "perception."

Hope that helps

 

[Reynard]

If the perception check relies upon sight, then it is at disadvantage.

Relies is not a defined term in D&D. Common usage means that it must be dependent, not just utilized. As such, if you could not perceive the thing without seeing it, then the penalty applies. If you could notice it due to sounds it makes (or via other senses) the penalty does not apply.

So, a creature using darkvision in dim light:

* Tries to spot a creature that is hidden. The creature is stationary, and isn't making any obvious noises. I would rule that the only sense that could detect the creature is sight, so the perception check is reliant upon the sight, and thus the -5 penalty applies.

* Tries to spot a creature that is hiding. The creature has been slowly moving up to do a sneak attack on the observing creature. Because they are moving around, the observer has a chance to hear their movement and there is no penalty to the perception check.

* Tries to spot a defect in a tapesty. If they use their hands as well as their eyes, no penalty. If they use only their eyes - penalty.

* Tries to hear something. No penalty.

* Says they want to look around in a cave. I'd look at what is there to be found and determine what it would take for the PC to be using a sense other than sight to find it. Then I'd ask them to describe how they are looking around and would either apply the penalty or not based upon whether they are relying upon sight, or are using a different sense in a way that would assist.

I think this is a pretty good breakdown (although I might quibble with the tapestry example depending on specifics). Generally, as long as those hiding have some concealment beyond the darkness and are laying in wait, the penalty applies. If they are moving around then the check is easily as reliant on hearing.

 

[Horwath]

Well, "passive" implies that you're not trying very hard. So yeah, disadvantage.

However, in the dark, it seems that the ears take up the burden of the eyes, so there's no net loss of "perception."

Hope that helps

That would be if the target is moving and trying to be quiet.

In case of an ambush, traps, secret doors or similar would all suffer penalties.

also hiding in combat, due to sounds of battle that would also maybe give disadvantage on perception based on sound, so you have disadvantage anyway you take on it.

also dim light might put penalty on other activities except perception: using thief tools(my favorite trick is blanket and continual flame under it), survival checks for tracking might get a penalty

 

[GMMichael]

That would be if the target is moving and trying to be quiet.

In case of an ambush, traps, secret doors or similar would all suffer penalties.

also hiding in combat, due to sounds of battle that would also maybe give disadvantage on perception based on sound, so you have disadvantage anyway you take on it.

also dim light might put penalty on other activities except perception: using thief tools(my favorite trick is blanket and continual flame under it), survival checks for tracking might get a penalty

Continual light? Are you one of those mages trying to put rogues out of business? And how long does it take your eyes to adjust after opening that lock?

To me, the real issue here is Asisreo's perfect storm of ambiguous D&D rules. Passive checks, perception, hiding rules... there's not a clear answer to be found. Except for one: rulings, not rules.

 

[Horwath]

Continual light? Are you one of those mages trying to put rogues out of business? And how long does it take your eyes to adjust after opening that lock?

actually not that much, but you need some kind on "hooded lantern" style of that continual flame,maybe like a headlight with a visor above your eyes, so the light goes on the target and not directly into your eyes.