How do you handle Blindsight?

[CorporateSlave]

Just wondering how different DM's and tables put Blindsight into effect? The RAW is simply:

"A creature with blindsight can perceive its surroundings without relying on sight, within a specific radius. Creatures without eyes, such as oozes, and creatures with echolocation or heightened senses, such as bats and true dragons, have this sense."

Do most people play this in the simplest interpretation; i.e. blindsight means if you are within range, no matter what, you are "seen" (perceived) by the creature?

Or do you play with certain "shades of gray" to this, for a more practical application? For example, echolocation could easily be foiled by the Silence spell, or any Obscurement that is solid in nature, such as thick brush. A glass window could foil echolocation or thermal-based senses, for example, although allowing perfect vision transparency.

Can a PC / NPC still attempt to Hide from a creature with Blindsight? Imagine a Rogue with carefully muffled equipment who stops moving, ducks into the dense fog, sprinkles a bland perfume or incense in the air to conceal their scent ... and hammers their Stealth check. Would you still allow automatic detection by any creature with Blindsight? Would it depend on the creature and how the RAW says their Blindsight works? Would they still have to make a Perception check? Would they count as being Unseen for Advantage/Disadvantage purposes when Attacking? (Simply being able to perceive the location still might not be the same as being able to directly observe every movement of every limb during an Attack)

Just wondering what other people think/have been doing. The RAW seems confusing in this regard.

[Lunali]

I treat it as if they had vision out to that radius, if you are within that radius it can see you unless you have some way of preventing that, such as cover/obscurement. What exactly qualifies as cover/obscurement depends a bit on how I interpret the senses of the creature.

[Demonslayer666]

I would allow things that provide total cover to interfere with blindsight, in most cases. Scent could carry around it though. It depends a lot on the situation and the creature involved.

[DMThac0]

It's very much situational and per creature basis.

An Ooze isn't remarkably intelligent, so it could be fooled by properly used terrain. It would know the area that it resides in, memorized and just going through the motions as it travels around. The party would be something foreign and the ooze would know it, so it goes to get food. The party hides behind a stone they'd pulled in front of a pocket in a wall, the ooze could be fooled by it. However the pseudopods would be searching every nook and cranny which may give away their hiding spot.

A warrior who's been blinded and has spent many years training after the fact gains blindsight. His skill allows him to know the location of the target(s) even if they're standing perfectly still, heightened senses allowing him to hear even the most minor of breaths or rustling fabric. His ability could be thwarted with too much sound however.

[Man_Over_Game]

Some creatures, like bats, have requirements for their Blindsense.

Officially, Blindsight does not see through cover, where Tremorsense does. You could have a hybrid of both, Blindsense, which allows a creature to both detect creatures without them touching the ground AND detects them through corners (like a Fireball) for creatures that use Echolocation.

[Chrizzt]

Thank you for the question. I was wondering about the same.

Right now my group delves through the underdark. My bat familiar has been invaluable in sniffing out those invisible duergars. Sometimes it was so easy rhat I asked myself if I made a mistake somewhere. Adlatus, the dark bat servant, has been shot last session, though..

[Spiritchaser]

I dislike the implementation of blindsight, because many creature descriptions do not detail how it works for that creature, and therefore what might be used to thwart it.

Generally speaking I’d say any full cover will always, or at least nearly always be effective in hiding from blindsight. Beyond that I have to appeal to houserules.

I typically use echolocation as a fill in, but that’s just me.

[darknite]

It works like sight but isn't effected by lack of light, invisibility, some illusions and the possessor isn't effected by the blinded condition.

[Nagog]

It works like sight but isn't effected by lack of light, invisibility, some illusions and the possessor isn't effected by the blinded condition.

This is usually how I interpret it, as stealth and such is also heavily affected by how much attention the character is paying. For example, I DMed for a character in Pathfinder that had 60 ft Blindsight as their only method of sight, so while they had pretty good perception there, they couldn't see past it, also while they had the capacity to sense things all around them, they aren't always paying full attention to what's going on around them. Kind of like when you're reading a book, you may not be paying attention to a dog wandering around the room. It's in your line of sight, and odds are it crosses the corner of your eye, but you're attention is currently being occupied by the book.

[CorporateSlave]

It works like sight but isn't effected by lack of light, invisibility, some illusions and the possessor isn't effected by the blinded condition.

That's always the way I'd thought of it; which is to say as long as you have some solid Obscurement (not just darkness/invisibility that Blindsight would theoretically peer right through), a suitably high Stealth roll might still evade the Blindsight - as it would imply stealthy silence, and maybe even skilled techniques to mask or scatter one's scent...or even covering your skin to foil the detection of body heat (think Dutch in the original Predator smearing himself with mud), but maybe just a thick cloak with a face cover or something.

[Greywander]

The problem with blindsight is that it isn't properly defined. A few specific stat blocks, such as the bat with its Echolocation, will tell you how it works, but otherwise there aren't really any general rules for describing how blindsight works. Which can be a problem if you're looking for ways to inhibit it, or at least understand the mechanism for it.

Any time you give someone blindsight, you should take care to describe how they use it, and what sorts of limitations it might have. As an example, I've done homebrew undead that can detach body parts and control them remotely. Each body part has blindsight out to 1 foot, but can only discern the tactile nature of things around it. So it's basically "feeling" (as in touching) whatever's immediately around it, but can't "see" things. It's not that hard for a body part to get lost, and all you've got to go on what what it feels around it (e.g. "Wood, maybe some kind of desk drawer?" or "Silk, feels like a pocket. I feel motion, like the person might be walking.").

In any case, you really have to figure out what the mechanism for blindsight is, otherwise all you can really do is "you can see out to this range, always, regardless of light or illusions or invisibility". In fact, I'm not sure how illusions would interact with blindsight. Presumably, an illusion would trick specific senses, e.g. a visual illusions manipulates light to trick the eyes, but blindsight would be some other sense that most people don't have, so there's little reason for an illusion to target that sense. Some stronger illusions might fool all senses by default, and thus would probably fool generic blindsight, but strictly visual illusions probably would not.

[darknite]

Be careful about making blindsight too powerful. It shouldn't provide a bubble of total awareness that can transcend cover, concealment, barriers and the like, though additional perceptive buffs like tremorsense might assist with this.

[Chronos]

Neither Stealth nor Perception specifies any particular sense or set of senses. Just like you can hide from sight and you can hide from hearing, you can also hide from esoteric senses.

It might be reasonable to impose disadvantage on someone trying to hide from a sense they're not personally familiar with, though.