Tremorsense Vs Stealth

[MadBear]

Based on a post I saw in another thread, I was curious how others treat Tremorsense vs stealth. Particularly, if a creature is on the ground touching it, would you allow a stealth followed by perception roll to see the creature, or would you say tremorsense allows you to pinpoint the creature if it's in range.

Curious what the forums thoughts on this are.

[MinotaurWarrior]

Based on a post I saw in another thread, I was curious how others treat Tremorsense vs stealth. Particularly, if a creature is on the ground touching it, would you allow a stealth followed by perception roll to see the creature, or would you say tremorsense allows you to pinpoint the creature if it's in range.

Curious what the forums thoughts on this are.

Just to be clear, you never do stealth that way. It's a stealth roll, which you immediately use to compare to monster's Passive Perception, and then a monster may use the search action to make an investigation or perception roll with a DC of the stealth check.

[OldTrees1]

Stealth applies against all forms of detection. Even against blindsight, telepathy, and future sight. Remember this stealth is used in a world with dragons and wishes, a Tier 4 stealth specialist should be level appropriate at stealth.


In the case of Temorsense, as someone gets better at stealth, they also get better at dissipating or mangling their disruptions in the ground. They know how to adjust their steps to be softer and know how to use a cloak and pebbles to fake vibrations elsewhere. They start to notice which parts of the ground are already noisy and learn to time their steps to camouflage with those noises.


At worst, stealth at disadvantage for tremorsense. Stealth at disadvantage and perception at advantage for future sight.

[Unoriginal]

Stealth applies against all forms of detection. Even against blindsight, telepathy, and future sight. Remember this stealth is used in a world with dragons and wishes, a Tier 4 stealth specialist should be level appropriate at stealth.


In the case of Temorsense, as someone gets better at stealth, they also get better at dissipating or mangling their disruptions in the ground. They know how to adjust their steps to be softer and know how to use a cloak and pebbles to fake vibrations elsewhere. They start to notice which parts of the ground are already noisy and learn to time their steps to camouflage with those noises.

This is true. Also worth noting that both Tremorsense and hearing are about perceiving vibrations, if with different organs. Being able to walk on the ground unperceived isn't that different if the perceiver is using hearing or tremorsense.

On the other hand, spells like Invisibility or Silence have no effect against someone using tremorsense, since they don't care about you being unseen or unheard (Silence nulls sounds, not other kinds of vibrations)

[cutlery]

I'd rule that tremorsense negates invisibility for the purposes of passive perception if A is using stealth.

They can't see A, but in this case (if A is walking on the floor) they don't need to.

A can get around this with levitate.

[Hellpyre]

As long as you took Darkstalker...wait, wrong edition.

More seriously, I'd argue tremorsense allows the same rough degree of fidelity as sight, and so could be hidden from by someone aware of a creature with tremorsense as a normal Stealth roll, or as a disadvantaged roll without. The creature may be aware of something moving, but if it was perfectly aware of its surroundings it should have full-on blindsight (which I do allow to pinpoint Stealth-using characters automatically).

For a more comical take, see Skyrim guards remarking "Must've been a rat" after taking an arrow to the eye. Knowing something is nearby doesn't always mean you know what is.

[Chronos]

Neither Stealth nor Perception specifies what senses they apply to. You can try to hide from tremorsense just like you can try to hide from sight or from hearing. Or, for that matter, hiding from smell: We know that creatures explicitly make Perception checks to smell things, because some creatures have advantage on it.

My table does rule, though, that if you're trying to hide from a sense that you personally don't have, you're at disadvantage.

[Mellack]

I think that if you do not have something that would block tremorsense, you cannot stealth. It is a precise sense by the game rules. In the same way that if you do not have something to block sight, you cannot stealth. The rules say that you need obscurement to even make the attempt against sight. If you are in an empty, well-lit hallway, you do not get a stealth check without some special feature. I consider tremorsence similar.

[OldTrees1]

I think that if you do not have something that would block tremorsense, you cannot stealth. It is a precise sense by the game rules. In the same way that if you do not have something to block sight, you cannot stealth. The rules say that you need obscurement to even make the attempt against sight. If you are in an empty, well-lit hallway, you do not get a stealth check without some special feature. I consider tremorsence similar.

But you do have something that would block / confuse / obscure tremorsense. Have you ever walked up a creaky stair? Have you ever tried to walk quietly up a creaky stair? A creaky stair is basically just converting more of the vibrations into noise. Likewise you can use posture, gait, cloaks, and sticks to obscure your "vibration form" and have it meld in with other "vibration forms" just like how camo is used to meld your visual form with other visual forms.

[Mellack]

But you do have something that would block / confuse / obscure tremorsense. Have you ever walked up a creaky stair? Have you ever tried to walk quietly up a creaky stair? A creaky stair is basically just converting more of the vibrations into noise. Likewise you can use posture, gait, cloaks, and sticks to obscure your "vibration form" and have it meld in with other "vibration forms" just like how camo is used to meld your visual form with other visual forms.

You are free to rule how you want, but I don't see anything about camo making it possible to hide when you are still in line of sight. It does not obscure you, which is the RAW requirement. Just as I would say it is impossible to hide in a bare, lit room, I would say it is equally impossible to hide from tremorsense when in contact with the ground.

I don't think comparing it to sound or smell is a good comparison. Those only give us general direction usually. Tremorsense says it can "can detect and pinpoint the origin" on any vibrations. That seems very specific and exacting.

[JellyPooga]

I think that if you do not have something that would block tremorsense, you cannot stealth. It is a precise sense by the game rules. In the same way that if you do not have something to block sight, you cannot stealth. The rules say that you need obscurement to even make the attempt against sight. If you are in an empty, well-lit hallway, you do not get a stealth check without some special feature. I consider tremorsence similar.

While generally I agree, I do wonder what you might consider to be concealment/obscurement against Tremorsense. What about these, for example;
- Standing in shallow water?
- Standing on a rug or other matting/decking/floor covering?
- Heavy underbrush?
- In the rain?
- A crowd? (If so, how many people counts as a "crowd"?)

[RSP]

Tremorsense, I imagine, would autobeat stealth more often than not.

You can’t hide if someone can see you clearly, and Tremorsense basically allows a new way to be seen clearly. Stepping “softer” is still stepping.

Could someone try and hide their footsteps among other triggering activities? Sure. Perhaps dropping marbles across a floor would confuse a Tremorsense creature briefly, but it would still know something is in that area.

I liken that strategy to using Shadow of Moil in bright light: you might not be seen, but certainly everyone knows someone/something is there.

[MinotaurWarrior]

You are free to rule how you want, but I don't see anything about camo making it possible to hide when you are still in line of sight. It does not obscure you, which is the RAW requirement. Just as I would say it is impossible to hide in a bare, lit room, I would say it is equally impossible to hide from tremorsense when in contact with the ground.

I don't think comparing it to sound or smell is a good comparison. Those only give us general direction usually. Tremorsense says it can " can detect and pinpoint the origin" on any vibrations. That seems very specific and exacting.

Tremorsense says it *can* be used to pinpoint a location, not that it automatically succeeds, just like darkvision and truesight say you can see in the dark or see invisible creatures - but an invisible wood elf, in the dark, hiding behind some tall grass, even though a creature with truesight and dark vision can see them, may still be hidden because they have skillfully made it difficult to take those sights and put them together into a coherent *perception* of what's in front of them.

And as you point out, RAW the requirement for hiding is strictly obscuration, defined in terms of sight. The game rules privilege that sense above all others. You do not require soundproofing, even against a creature with great hearing like a bat, or scent masking, even against a scent hound or a star-nosed mole.

In fiction, by far the most famous and influencial story about a creature with Tremorsense is Frank Herbert's Dune, where mundane people regularly hide from Tremorsense by moving in a special way that the vibrations they make seem to not be coming from a human. They don't prevent themselves from creating vibrations, they simply use their skill so that the sense information they generate isn't perceptible as a human by the sandworms. As a Sci fi story, there's obviously a lot of spectacular stuff there, but I've never heard a reader complain that those sections of on-foot desert travel broke their suspension of disbelief or lacked verisimilitude.

And in reality, there are many animals that sense vibration, and a few that intentionally mask themselves with it. For example, Stenolemus bituberus creates a fake "image" of a caught fly to lure spiders into striking range, by making vibrations that "look like" a trapped, struggling fly.

[Mellack]

While generally I agree, I do wonder what you might consider to be concealment/obscurement against Tremorsense. What about these, for example;
- Standing in shallow water?
- Standing on a rug or other matting/decking/floor covering?
- Heavy underbrush?
- In the rain?
- A crowd? (If so, how many people counts as a "crowd"?)

Personal opinions on these:
Shallow water wouldn't work, you are still stepping on the ground. Swimming would work.
Decking would be great. You are off of the ground.
I don't think underbrush would help at all.
Rain probably wouldn't be enough. Perhaps a downpour or a hailstorm would work.
A crowd wouldn't hide your steps, but it would make it hard to follow you in particular.

[JellyPooga]

Personal opinions on these:
Shallow water wouldn't work, you are still stepping on the ground. Swimming would work.
Decking would be great. You are off of the ground.
I don't think underbrush would help at all.
Rain probably wouldn't be enough. Perhaps a downpour or a hailstorm would work.
A crowd wouldn't hide your steps, but it would make it hard to follow you in particular.

Some points to consider and perhaps reconsider some of your answers (NB - I'm not advocating any particular stance here, only pointing out my own thoughts on the matter and the possible repercussions);

- Shallow water: Consider how water disperses both sound and light. You can usually see someone fully submerged, but unless the water is very still, not well. Sound is even further obfuscated. Now while I would agree that a puddle or water shallow enough that your ankles aren't getting wet isn't going to have much, if any, effect on Tremorsense, anything deeper might well make a precise or accurate location much harder to ascertain. Remember that we're not talking about being invisible to Tremorsense (which would be an auto-fail in the same way that visual invisibility is to regular vision and Darkvision), only looking for concealment or obscurement. As the water moves and ripples, the vibrations or pressure that Tremorsense detects might be diffused enough to act like dim light to regular vision.

- In the same vein, decking that removes you from the same surface might not make you entirely invisible to Tremorsense if the decking is in contact with the surface the Tremorsensing creature is on. This might be considered heavy obscurement, for example

- Moving through heavy underbrush or a crowd might create "noise" that could make pinpointing a location difficult or impossible. Consider that, as you mentioned, Tremorsense is a precise sense in the same way that vision is. The more sensitive the detecting equipment, the easier it is to overload or confuse it. A flash of bright light, for example, often causes temporary blindness, or for a better analogy to the underbrush/crowd example, constant glare makes vision difficult; think how difficult it is to face the sun when it's low and bright and further, how someone might use that to conceal themselves from your sight; you might know someone or something is there, but accurately locating them is not so easy. I'll remind you again that we're talking about someone taking advantage of an impairment of sense to make a Stealth check, not be totally invisible.

- Rain. While it might be easy to think of rain in the same way as a crowd or underbrush; creating enough "noise" to conceal someone, it might not be so simple. Perhaps because of the regularity and predictability of rainfall (whether it's heavy, hail, or whatever), makes it less of an inconvenience than the chaotic and unpredictable nature of a moving crowds footfalls, or the intermittent movement of disturbed brambles and ferns. Then again, it might also be just like the other two.

I'd be interested to hear your own or anyone elses thoughts on these or other examples.

[JackPhoenix]

Some points to consider and perhaps reconsider some of your answers (NB - I'm not advocating any particular stance here, only pointing out my own thoughts on the matter and the possible repercussions);

- Shallow water: Consider how water disperses both sound and light. You can usually see someone fully submerged, but unless the water is very still, not well. Sound is even further obfuscated. Now while I would agree that a puddle or water shallow enough that your ankles aren't getting wet isn't going to have much, if any, effect on Tremorsense, anything deeper might well make a precise or accurate location much harder to ascertain. Remember that we're not talking about being invisible to Tremorsense (which would be an auto-fail in the same way that visual invisibility is to regular vision and Darkvision), only looking for concealment or obscurement. As the water moves and ripples, the vibrations or pressure that Tremorsense detects might be diffused enough to act like dim light to regular vision.

- In the same vein, decking that removes you from the same surface might not make you entirely invisible to Tremorsense if the decking is in contact with the surface the Tremorsensing creature is on. This might be considered heavy obscurement, for example

- Moving through heavy underbrush or a crowd might create "noise" that could make pinpointing a location difficult or impossible. Consider that, as you mentioned, Tremorsense is a precise sense in the same way that vision is. The more sensitive the detecting equipment, the easier it is to overload or confuse it. A flash of bright light, for example, often causes temporary blindness, or for a better analogy to the underbrush/crowd example, constant glare makes vision difficult; think how difficult it is to face the sun when it's low and bright and further, how someone might use that to conceal themselves from your sight; you might know someone or something is there, but accurately locating them is not so easy. I'll remind you again that we're talking about someone taking advantage of an impairment of sense to make a Stealth check, not be totally invisible.

- Rain. While it might be easy to think of rain in the same way as a crowd or underbrush; creating enough "noise" to conceal someone, it might not be so simple. Perhaps because of the regularity and predictability of rainfall (whether it's heavy, hail, or whatever), makes it less of an inconvenience than the chaotic and unpredictable nature of a moving crowds footfalls, or the intermittent movement of disturbed brambles and ferns. Then again, it might also be just like the other two.

I'd be interested to hear your own or anyone elses thoughts on these or other examples.

Tremorsense isn't vision-based, so it's not affected by obscurement. It's not precise sense like sight (or blindsight), it allows you to tell where the enemy is, not how does it look like, or what it's doing. It makes hiding impossible (because being hidden means your location is not known, nothing else), but it does not make you unseen: It wouldn't remove the disadvantage to attacks or the advantage for the attacker, it just allows you to know the enemy's position.

[JellyPooga]

Tremorsense isn't vision-based, so it's not affected by obscurement. It's not precise sense like sight (or blindsight), it allows you to tell where the enemy is, not how does it look like, or what it's doing. It makes hiding impossible (because being hidden means your location is not known, nothing else), but it does not make you unseen: It wouldn't remove the disadvantage to attacks or the advantage for the attacker, it just allows you to know the enemy's position.

Strict RAW, I won't argue. Stealth only functions to act "without being seen or heard", which excludes any attempt to foil any sense that isn't based on sight or hearing, which would include Tremorsense.

I, however, consider that an oversight. I would not run my game that way and would consider anyone who does, frankly, a little bit daft. Plenty of examples have been given in this thread already, short though it may be, of how Stealth might function against Tremorsense or how a character might attempt to foil it and any declaration of "impossible" is merely adding to the Guy at the Gym syndrome, in my opinion.

For me, Tremorsense is just another sense. As such, it is as fallible as any other and Stealth works just fine against it...provided adequate concealment or obscurement (as in, the english language term and not necessarily in the specific rule sense, which, as you mention, arguably only provides for visual obscurement). Discussing what might or might not constitute concealment sufficient to roll Stealth against Tremorsense is what I'm interested in here and not the RAW, because the written rules are woefully lacking in this regard.

[Demonslayer666]

I would allow a Stealth check to evade it, but it would be a high DC and or at disadvantage depending on the situation.

Tremorsense is like hearing, but you can "hear" things much softer than sounds, because sounds carry through solid objects much further. In this case, the ground.

Tremorsense would work under water, but at a reduced range. Sounds carry further under water too, but not as well as solids.

[OldTrees1]

For me, Tremorsense is just another sense. As such, it is as fallible as any other and Stealth works just fine against it...provided adequate concealment or obscurement (as in, the english language term and not necessarily in the specific rule sense, which, as you mention, arguably only provides for visual obscurement). Discussing what might or might not constitute concealment sufficient to roll Stealth against Tremorsense is what I'm interested in here and not the RAW, because the written rules are woefully lacking in this regard.


Tremorsense
A monster with tremorsense can detect and pinpoint the origin of vibrations within a specific radius, provided that the monster and the source of the vibrations are in contact with the same ground or substance.

Okay so we have some useful details here.
1) Tremorsense is detecting and pinpointing the origin of vibrations. In a rainstorm an Ankheg notices every raindrop, but not as a raindrop. They detect each vibration (only indirectly detecting the impact) and can pinpoint each of those origins of vibration. So if hunting in a storm, an Ankheg will constantly have thousands of instantaneous blips on their radar. However there might be a repeating pattern of 4 blips that reappear every second but moved to the NW. Maybe that is a quadruped running?
2) The monster and the source have to be in contact with the same substance. If I am hiding in a young sapling from an Ankheg in the ground below, I am not in contact with the same substance as the Ankheg, but the Sapling is. My vibrations will be indirectly noticed by the Sapling causing vibrations against the ground. The Ankheg does not see the roots, but it notices cylindrical sources of vibrations. Also I hope the Ankheg does not touch the Tree and see me up here (then it would be like the Ankheg and I were swimming in a lake).


So I think the following are relevant ways to confuse the Ankheg:
1) Signal/Noise ratio. Have lots of vibrations with lots of origins. That will make it harder to know and track the source it wants to.
2) Muffled / Distorted. Having a substance between you and the ground will already make it see the substance instead of you. However that does not help unless the substance has a vibration that looks different from you. Boots don't really help. But a blanket or a unicycle might.
3) Dampen. It detects vibrations. Having quieter vibrations can make it not notice you among the baseline it gets all the time.
4) Interference. Technically vibration is a wave and technically you can cancel those out. So technically an Invisible to Tremorsense spell could be possible.

[Mellack]

Some points to consider and perhaps reconsider some of your answers (NB - I'm not advocating any particular stance here, only pointing out my own thoughts on the matter and the possible repercussions);

- Shallow water: Consider how water disperses both sound and light. You can usually see someone fully submerged, but unless the water is very still, not well. Sound is even further obfuscated. Now while I would agree that a puddle or water shallow enough that your ankles aren't getting wet isn't going to have much, if any, effect on Tremorsense, anything deeper might well make a precise or accurate location much harder to ascertain. Remember that we're not talking about being invisible to Tremorsense (which would be an auto-fail in the same way that visual invisibility is to regular vision and Darkvision), only looking for concealment or obscurement. As the water moves and ripples, the vibrations or pressure that Tremorsense detects might be diffused enough to act like dim light to regular vision.

- In the same vein, decking that removes you from the same surface might not make you entirely invisible to Tremorsense if the decking is in contact with the surface the Tremorsensing creature is on. This might be considered heavy obscurement, for example

- Moving through heavy underbrush or a crowd might create "noise" that could make pinpointing a location difficult or impossible. Consider that, as you mentioned, Tremorsense is a precise sense in the same way that vision is. The more sensitive the detecting equipment, the easier it is to overload or confuse it. A flash of bright light, for example, often causes temporary blindness, or for a better analogy to the underbrush/crowd example, constant glare makes vision difficult; think how difficult it is to face the sun when it's low and bright and further, how someone might use that to conceal themselves from your sight; you might know someone or something is there, but accurately locating them is not so easy. I'll remind you again that we're talking about someone taking advantage of an impairment of sense to make a Stealth check, not be totally invisible.

- Rain. While it might be easy to think of rain in the same way as a crowd or underbrush; creating enough "noise" to conceal someone, it might not be so simple. Perhaps because of the regularity and predictability of rainfall (whether it's heavy, hail, or whatever), makes it less of an inconvenience than the chaotic and unpredictable nature of a moving crowds footfalls, or the intermittent movement of disturbed brambles and ferns. Then again, it might also be just like the other two.

I'd be interested to hear your own or anyone elses thoughts on these or other examples.

I would point out that water carries vibrations very well. Whales can communicate for many miles because water carries sound wave (and other low frequency waves like tremors presumable would be) both faster and farther than air will. The main difficulty would be the change from water to the earth, much like how water to air does.


I can see rain being either making detection harder like trying to hear a conversation over a loud steady noise, or not hurt at all because it would be a difference against a steady background.

Since humans do not have any experience with such a sense, it requires the GM to make rulings as to how they think it should work. I can see valid reasoning for different interpretations.

[Bloodcloud]

I would definitely rule that you can stealth against tremorsense, maybe even with advantage if you researched that particular creature. But I would genrally require specificaly stealthing from tremorsense.

Dune, after all, definitely has the Fremens doing stealth check against sandworms.

[Sindeloke]

Mud feels like the best solution to tremorsense, short of hovering. Organic ground cover like thick moss, wet decaying leaves, or similar, would also help a lot. Sand would realistically probably be a pain too, despite the Dune heritage of the concept. Snow, too. Anything relatively soft, springy, or yielding.

[Tanarii]

IIRC like surprise, Hiding is written in an ambiguous way. As in, the DM determines when it happens, followed by mechanics. It's just not written in a "and this mechanic is the mandated method" fashion.

So potentially, as long as the DM determines your PC has done something to allow them to hide from any applicable perceptions, it's a Dexterity (Stealth) vs (usually passive) Wisdom (Perception) contest. Even those ability scores and proficiencies may vary if they use the variant rule. And then it'd be modified by the best applicable sense.

So if you can't be seen, might be smelled, and definitely will be tremor'd, you wouldn't roll and would be detected.

If you couldn't be seen, might be tremor'd, and might be smelled (at advantage), you would roll vs their advantage perception.

This is the same problem people run into with "do you auto-detect someone not hiding who is invisible?" Yes, if you auto detect them through any other sense. Some kind of check if any other sense might detect them. Automatically don't detect if no sense can detect.

[Spiritchaser]

I don’t think it’s too much of a stretch to extend the existing stealth rules to tremorsense, or indeed to blindsight (blindsight is nessesarily harder because, notwithstanding bats, it’s mechanism is generally not explained) in any case, to have a chance for stealth to succeed, the observer must not be able to see you clearly. Well just swap that for “perceive clearly”.

The difficulty comes with trying to decide what defines “clearly” in this context.

A certain amount of background vibration could be equated as something to “ hide behind” but how much is enough? Are other creatures sufficient? If so, how many are needed before one more might escape notice. Could you try and time your steps with another creature to roll stealth? How about standing in a river? For whatever it’s worth, I do allow this last (standing in moving water) to provide the opportunity.

Other methods might include standing on something that might be particularly poor at transmitting vibrations. Gaps between where one is standing and the ground might also help, though trying to come up with a remotely consistent set of guidelines is more than I’ve ever done.

Look on the bright side. However much this is irritating to rule on, it’s better than blindsight. For blindsight you must first decide for each creature, how it’s blindsight works before you can figure out what (If anything) might be done to hide from it.

[JackPhoenix]

I would definitely rule that you can stealth against tremorsense, maybe even with advantage if you researched that particular creature. But I would genrally require specificaly stealthing from tremorsense.

Dune, after all, definitely has the Fremens doing stealth check against sandworms.

People keep using that example, but that's now what happened in Dune. They didn't hide from the sandworms, they just figure how to move to get the sandworms to ignore them. The worms still knew about them, but only attacked when the vibrations came in certain regular patterns.

[Tanarii]

People keep using that example, but that's now what happened in Dune. They didn't hide from the sandworms, they just figure how to move to get the sandworms to ignore them. The worms still knew about them, but only attacked when the vibrations came in certain regular patterns.
Did they only use thumpers as a distraction in the movie?

[iTreeby]

How do people feel about the magic item, boots of elven kind /and or the spell silence vrs tremor sense enemies? How about pass without trace? There are some very common effects that might be worth considering.

[JackPhoenix]

Did they only use thumpers as a distraction in the movie?

I'm not sure about the name, the version I've read was translated. But they've used them to call the worm from a distance so they could mount it... a single human walking carelessly would still get attacked if the worm was around, but the device naturally had a longer range.

[Chronos]

A more recent, and perhaps more familiar to modern players, example of tremorsense is Toph, from Avatar: the Last Airbender. She's an extremely skilled earthbender, and uses tremorsense to make up for being eye-blind. And she really doesn't like loose sand, because it makes it hard for her to "see" anything.

I'm not sure whether her version of Tremorsense would work at all on non-earthen surfaces (like a wooden floor), though.

[MinotaurWarrior]

People keep using that example, but that's now what happened in Dune. They didn't hide from the sandworms, they just figure how to move to get the sandworms to ignore them. The worms still knew about them, but only attacked when the vibrations came in certain regular patterns.

The worms sensed vibrations, but they didn't perceive their trigger for attacking - regular patterns of movement. The Fremen's footsteps blended in the background of wind-blown, shifting, and settling sand. Shai-hulud didn't perceive them as "good, random humans" it didn't perceive them as humans, because the sense impressions they left didn't fit it's pattern for "thing I should attack".

Same as how when someone is obscured, you can still see them, but you might not be able to match what you see to the pattern you have for them. E.g. a deer behind foliage. I see a lot of tan, black, and brown spots between leaves (the deer) but they are not clearly forming the shape of a deer. I don't perceive it as a deer. (https://live.staticflickr.com/6174/6145767781_f09f668708.jpg)


I don’t think it’s too much of a stretch to extend the existing stealth rules to tremorsense, or indeed to blindsight (blindsight is nessesarily harder because, notwithstanding bats, it’s mechanism is generally not explained) in any case, to have a chance for stealth to succeed, the observer must not be able to see you clearly. Well just swap that for “perceive clearly”.

Or keep it at "see clearly", what's in the rules, and if a being with tremorsense cannot see you, you can hide. But if it can't see, smell, touch, hear, or taste you (for example - because you are separated from it by several feet of earth as it burrows underground) it can still detect you via tremorsense.

[Hellpyre]

A more recent, and perhaps more familiar to modern players, example of tremorsense is Toph, from Avatar: the Last Airbender. She's an extremely skilled earthbender, and uses tremorsense to make up for being eye-blind. And she really doesn't like loose sand, because it makes it hard for her to "see" anything.

She has something a bit more precise than what tremorsense is described as. Arguably, what she has is blindsight (with the previous poster's caveat that you need to figure out how her blindsight works to rule on hiding from it) that can't see objects not touching a surface continuous with the one she is on.

Especially since it's implied that she sends out vibrations to get the sight, rather than it just all passively filtering back to her.

[Tanarii]

Tangent: Would you allow blindsight to work:
- in a vacuum?
- Through water?
- throuh foliage? (Concealment but actual physical matter)
- Through walls? (Hard cover)
- In high winds?
- in a rainstorm?

[Valmark]

I rule it as it works in Tremors, more or less.

So auto-detect, but you don't know what it is. If someone throws a stone, you have no idea which is what. Though a smart creature with Tremorsense could guess.

[Telok]

I always just considered tremorsense to be dirt & rock based hearing for burrowing creatures. Pretty much on par with regular hearing, maybe like submarine sonar without the pinging. People can understand that concept.

Oddly the whole "same substance" thing, and not being any kind of parallel to human sense, make it a weird magic radar that's blocked by a blanket on the ground. Or ice and thick snow, now that I think about it. That substance limit stops at the edge of the dirt or rock the creature is burrowing through, which wouldn't be the ice/snow being walked on.

Of course by the rules tremorsense has no possible interaction with stealth or perception because it's not sight or hearing and those are the only senses the rules care about.

[OldTrees1]

Tangent: Would you allow blindsight to work:
- in a vacuum?
- Through water?
- throuh foliage? (Concealment but actual physical matter)
- Through walls? (Hard cover)
- In high winds?
- in a rainstorm?

Depends on the blindsight, but yes.

For example:
A Bat's blindsight depends on sound waves. It would travel through gas / liquid, rebound off of solids, and disappear in a vacuum. So things that make noise or dampen noise would impair the sight.
But a Wraith's Lifesense (in 3E, not ported to 5E) depends on life force. It would travel through any non living matter but could not distinguish between living creatures if they are sufficiently healthy.


Oddly the whole "same substance" thing, and not being any kind of parallel to human sense, make it a weird magic radar that's blocked by a blanket on the ground. Or ice and thick snow, now that I think about it. That substance limit stops at the edge of the dirt or rock the creature is burrowing through, which wouldn't be the ice/snow being walked on.

If I walk on the snow, the snow gets pushed into the ground. This causes the vibrations in the ground. So the radar still detects things beyond the blanket BUT only indirectly by the affect on the boundary.

[Tanarii]

Of course by the rules tremorsense has no possible interaction with stealth or perception because it's not sight or hearing and those are the only senses the rules care about.
Lots of creatures get advantage on perception checks involving a sense of smell.


Depends on the blindsight, but yes.
Yeah. I guess my questions don't really make sense. Since it's a catch all and the how is variable.

[OldTrees1]

Yeah. I guess my questions don't really make sense. Since it's a catch all and the how is variable.

I edited in the 2nd half of the answer. It is a broad question, so it gets a broad answer.


For example:
A Bat's blindsight depends on sound waves. It would travel through gas / liquid, rebound off of solids, and disappear in a vacuum. So things that make noise or dampen noise would impair the sight.
But a Wraith's Lifesense (in 3E, not ported to 5E) depends on life force. It would travel through any non living matter but could not distinguish between living creatures if they are sufficiently healthy.

So, yes vacuum and foliage could stop some blindsight, and every blindsight can be confused by increasing the noise/signal ratio.

[Tanarii]

, and every blindsight can be confused by increasing the noise/signal ratio.
Oh yes. I assume two things that are often ignored for these kinds of discussions:

- distance matter for "signal" strength. This one is less ignored when distance is specified, ie Darkvision or Tremorsense or Blindsight. But it's critical for making a DM on ruling on, for example, can you hear a non-hiding invisible or concealed creature.

- "noise" matters. Combat is definitely noisy, and will impact the ability to hear a non-hidden concealed creature. For tremor sense, it's more arguable because it specifies pin point, but a creature might be able to conceal itself among an army or beneath a Dune-like Thumper. For blindsight it'd depend on the how.

[OldTrees1]

- "noise" matters. Combat is definitely noisy, and will impact the ability to hear a non-hidden concealed creature. For tremor sense, it's more arguable because it specifies pin point, but a creature might be able to conceal itself among an army or beneath a Dune-like Thumper. For blindsight it'd depend on the how.

For Lifesense, a flock of birds could be used to conceal the location of a Druid. Which of those healthy life signs is the Druid, which is another rock pidgeon, and which is the Druid's pet Roc.

[Tanarii]

For Lifesense, a flock of birds could be used to conceal the location of a Druid. Which of those healthy life signs is the Druid, which is another rock pidgeon, and which is the Druid's pet Roc.
Its not which is which, so much as it's going undetected because you can't be clearly "seen". Slightly different.

And also context matters. Is the life-sensor going to ignore all those life-sensed as a threat? That matters for surprise purposes, and attempting to launch an ambush from within the flock. Ditto for trying to ambush vs tremor sense by sneaking up using ambient tremors as cover. let's say they're next to an operating drop hammer for some reason. I'd assume in that case they'd be tuning out the hammering. :smallamused:

[Telok]

Lots of creatures get advantage on perception checks involving a sense of smell.
Quite right, my bad. I don't recall any other information on scent perception beyond some critters getting advantage. Do you recall if there's anything beyond the "critter gets advantage" for scent perception anywhere?


If I walk on the snow, the snow gets pushed into the ground. This causes the vibrations in the ground. So the radar still detects things beyond the blanket BUT only indirectly by the affect on the boundary.
Interesting, I'd missed that they actually used the word 'vibrations'. This edition goes back and forth between total handwavium and extremely precise, explicit, near-legalese in the weirdest places. It keeps throwing me off.

However that does make it the equal of hearing as a sense. Therefore you default to the "unseen but heard" rules and can make stealth checks by just standing still.

Unless you want to rule that tremorsense is sensitive enough to detect heartbeats and breathing, but then it would hear regular sounds as those vibrations of the air are transmitted to the ground. That would mean it could hear flying creatures and people climbing, not pinpoint then but definitely hear them.

[Tanarii]

Quite right, my bad. I don't recall any other information on scent perception beyond some critters getting advantage. Do you recall if there's anything beyond the "critter gets advantage" for scent perception anywhere?

Not to my knowledge. Which means the DM has to use a lot of judgement, just as with hearing. Because many creatures can perceive by smell when the chance of a human doing so is Nope, No Check.

Same with hearing. The human range is a normal convo sounds like a whisper at 30ft, and a loud one at 60ft, more or less. Which means pinpointing an archer in a fog cloud by hearing at 300ft who isn't using Stealth is ... unlikely.

Which makes Tremorsense hard to judge. We don't even have real world comparisons to judge against. We've got things like Tremors and Dune.

[JackPhoenix]

Which makes Tremorsense hard to judge. We don't even have real world comparisons to judge against. We've got things like Tremors and Dune.

Well, we've got spiders and snakes....

[Tanarii]

Well, we've got spiders and snakes....
Okay sure. In the real world, I've got no basis for judging it. Because I've no idea how it works for spiders or snakes. :smallamused:

[Spiritchaser]

Tangent: Would you allow blindsight to work:
- in a vacuum?
- Through water?
- throuh foliage? (Concealment but actual physical matter)
- Through walls? (Hard cover)
- In high winds?
- in a rainstorm?

I generally pick either echolocation or thermal-imaging for a creature’s blindsight, and some of the answers would be different for each...

Though I do have to ask... have you ever actually confronted dungeons and dragons players with a vacuum?

[Hellpyre]

Though I do have to ask... have you ever actually confronted dungeons and dragons players with a vacuum?

I've been in a lich's lair once that was an airless vacuum filled with constructs and undead.

[OldTrees1]

I generally pick either echolocation or thermal-imaging for a creature’s blindsight, and some of the answers would be different for each...

Though I do have to ask... have you ever actually confronted dungeons and dragons players with a vacuum?

Yes, it was a trap my dungeon guide PC survived. We were playing a 5E hardcover.

Many years earlier, while I was DMing the party went to a moon.

[Chronos]

Blindsense can get even more complicated when it works in multiple ways. IIRC, for dragons, it's a result of their keen hearing and smell. So does that mean that they lose it entirely when one of those is negated, or keep it as long as one isn't negated? Maybe disadvantage if one is negated but not the other?

[OldTrees1]

Blindsense can get even more complicated when it works in multiple ways. IIRC, for dragons, it's a result of their keen hearing and smell. So does that mean that they lose it entirely when one of those is negated, or keep it as long as one isn't negated? Maybe disadvantage if one is negated but not the other?

Fortunate typo (in bold). You could also rule that negating a component of the Blindsight (as if seen) degrades it to only Blindsense (as if located). 3E had that distinction. I kinda wonder if they answered this question in Draconomicon.