How effective is tremorsense?

[Crow_Nightfeath]

Like can tremorsense sense it's surroundings? Like if you don't have normal sight would you run into things?

[Jack_Simth]

Like can tremorsense sense it's surroundings? Like if you don't have normal sight would you run into things?
Well, you know where stuff is when it's in contact with the ground (or at least, what square it's in).
A nice vertical wall? You're not going to walk into that.
A low hanging tree branch? Hope you weren't running.
Oh, the ground is uneven here? You can't really see where you're placing your feet well enough to pick your foot's angle well. Better go slow.
You're also not going to have a "fun" time trying to pick up that penny. You know where it is... to within a five foot square. It's 3/4ths of an inch across. If you reduce the "grid" to the penny's size, there's... 6400 squares it might be in that five-foot square, that you can't distinguish with tremorsense.

[Knaight]

Here's the exact phrasing of tremorsense:

A creature with tremorsense automatically senses the location of anything that is in contact with the ground and within range. Aquatic creatures with tremorsense can also sense the location of creatures moving through water.

If no straight path exists through the ground from the creature to those that it’s sensing, then the range defines the maximum distance of the shortest indirect path. It must itself be in contact with the ground, and the creatures must be moving.

As long as the other creatures are taking physical actions, including casting spells with somatic components, they’re considered moving; they don’t have to move from place to place for a creature with tremorsense to detect them.

Some of this is a little ambiguous. Most notably, "automatically senses the location of anything that is in contact with the ground and within range" straight out contradicts the requirement for movement. There's a few ways to resolve this, of which the cleanest is to assume that "anything" is defined to specifically exclude creatures, which operate according to their own rules.

[Luckmann]

Seen Avatar: The Last Airbender? Toph. Toph has tremorsense.

[Willie the Duck]

Some of this is a little ambiguous. Most notably, "automatically senses the location of anything that is in contact with the ground and within range" straight out contradicts the requirement for movement. There's a few ways to resolve this, of which the cleanest is to assume that "anything" is defined to specifically exclude creatures, which operate according to their own rules.

And clearly focused on targeting creatures. If you take "Aquatic creatures with tremorsense can also sense the location of creatures moving through water" literally, it means that aquatic creatures using tremorsense who are more than their TS radius from ground can only sense creatures (but not boats, unless they are big enough to be considered a form of ground unto themselves), and only when they are moving.

Assuming that the text is being overly specific since targeting opponents is a big part of the game, I'd say that Tremor sense allows you to know the distance, size, and relative shape (I doubt you could get police-sketch-level facial details, but you could tell a tree with leaves from a tree without) of anything on the ground. Unlike the old TSR-era question of how infravision allowed a dwarf to detect the room temperature pit in the room temperature floor or the like, drop-offs and the like are exceedingly obvious. Reading your spellbook? Light a candle.

[Bronk]

Like can tremorsense sense it's surroundings? Like if you don't have normal sight would you run into things?

Looks like you can sense anything touching the ground, so you wouldn't run into things.

As for anything else on the ground, you can 'pinpoint' it, so you know exactly where it is (I don't see a rule anywhere setting this to a 5 foot square minimum), but if you aren't using a visual sense as well it's still invisible to you, so if you try to interact with it or attack it, it (whatever or whoever it is) would get the 50% miss chance from the invisibility section (or the blindness section).

It seems weird that you can detect non-moving objects touching the ground, but then again, maybe they're affected by background vibrations or something. That would tie in thematically with the aquatic aspect of the ability.

[Knaight]

Assuming that the text is being overly specific since targeting opponents is a big part of the game, I'd say that Tremor sense allows you to know the distance, size, and relative shape (I doubt you could get police-sketch-level facial details, but you could tell a tree with leaves from a tree without) of anything on the ground. Unlike the old TSR-era question of how infravision allowed a dwarf to detect the room temperature pit in the room temperature floor or the like, drop-offs and the like are exceedingly obvious. Reading your spellbook? Light a candle.

I would definitely read that as letting creatures who stay stock still hide from tremorsense - the specification of moving and then clarification of what counts as moving strongly suggests it. Meanwhile things that are better rooted to the ground would be generally detectable.

[Bronk]

I would definitely read that as letting creatures who stay stock still hide from tremorsense - the specification of moving and then clarification of what counts as moving strongly suggests it. Meanwhile things that are better rooted to the ground would be generally detectable.

They must know something is there, but not what... I don't think the ability mentions automatic identification, just knowledge of location.

People sneaking up on a creature with tremorsense would be automatically pinpointed, unless they could do it without moving, like with (silent spell, still spell) teleportation. If the creature flew in, and everyone already present weren't detected and stayed still afterwards, they wouldn't be detected either...

[Knaight]

People sneaking up on a creature with tremorsense would be automatically pinpointed, unless they could do it without moving, like with (silent spell, still spell) teleportation. If the creature flew in, and everyone already present weren't detected and stayed still afterwards, they wouldn't be detected either...

It's very much a defensive application, yes - freeze when the creature comes by, wait for it to leave, start moving again. That said the silent/still spells (or any psionics) does allow some attacking, though odds are pretty good that doesn't hold up well in any but the most featureless plains.

[Luckmann]

Looks like you can sense anything touching the ground, so you wouldn't run into things.

As for anything else on the ground, you can 'pinpoint' it, so you know exactly where it is (I don't see a rule anywhere setting this to a 5 foot square minimum), but if you aren't using a visual sense as well it's still invisible to you, so if you try to interact with it or attack it, it (whatever or whoever it is) would get the 50% miss chance from the invisibility section (or the blindness section).

It seems weird that you can detect non-moving objects touching the ground, but then again, maybe they're affected by background vibrations or something. That would tie in thematically with the aquatic aspect of the ability.Think of it like this; you (and everything else that moves) creates vibrations, too, that reverberate in the ground like an echo.

It's like a form of radar, except it works by sensing tremors in the ground.

[martixy]

A picture is worth a thousand forum posts. A moving picture - ten thousand.
Just do Toph.