Please help me workshop some changes that I'm making to Hide and Invisible. Fundamentally, I'm trying to provide more codification to aspects that seem far too vague to be of use right now. Specifically, I do not like the fact that it confers the "Invisible Condition" with the very vague fail state of "being found", or that a player can't simply "stop being hidden" if the list of fail states is treated as exhaustive. I decided on a different condition, called "Unseen" (or, perhaps "Hidden"?), that magical invisibility also confers, and has the same benefits as the current Invisible Condition. The Invisible Condition, by extension, gets all of those benefits as well as actually being Invisible to the naked eye (strangely, that doesn't seem to actually be a part of invisibility). The main benefit of Invisible, then, is to be able to move out into the open and remain unseen until Invisibility somehow wears off.

This unseen/hidden condition is similar to "Frightened" in that you can have the condition against some creatures, but not others, and the benefits of being Unseen are only against those creatures who treat you as having that condition.

The main things I'd want to have happen are:
1. Someone who is hidden cannot be targeted by attacks, spells, or effects that require line of sight.
2. Someone who is hidden gains advantage on attacks against creatures they are unseen to. They lose the unseen condition once the attack hits or misses.
3. Someone who is hidden gets advantage on initiative rolls when combat starts.
4. Someone who is hidden will lose this condition if they do any of the current listed things in the Hide Action, in addition to simply deciding not to be hidden any more.
5. Someone who his hidden uses their Hide Roll as a DC against the Search Action to find them, but only if the searcher is in a position where the hidden creature is not in total cover.
6. Someone who is hidden can leave cover on their turn and keep the unseen condition against other creatures unless one of the following happens:
6a. An attack they make hits or misses.
6b. They end their turn outside of 3/4 cover, full cover, or heavy obscurement.
6c. They cast a spell.
6d. They make a sound louder than a whisper.
6e. A creature has a passive perception score above their DC set by the Hide Roll.

Essentially, I want rogues to be able to attack at range while hidden for advantage (and sneak attack), and also to be able to sneak up on someone, as long as they do it quickly (within the turn) and somehow remain unseen until they attack (beat the passive perception of the victim), and also dart from cover to cover. But I don't want them to be able to make a single roll, then walk around in broad daylight flapping their arms around like idiots and somehow remain "Invisible". They would actually need magical invisibility to do that.

Here is what I've come up with:

Invisible [Condition]

While Invisible, you are completely transparent and cannot be seen by ordinary sight.

You automatically have the Unseen Condition to creatures that rely on sight unless they can perceive invisible creatures through a special sense, magical effect, or similar feature. The Unseen Condition cannot end on you unless the Invisible Condition also ends.

Unseen [Condition]

A creature can be Unseen to some creatures but not others. Whenever a rule refers to a creature being Unseen, it applies only against creatures for whom the condition exists.

While Unseen to a creature:

Concealed: You cannot be targeted by attacks, spells, or effects that require the creature to see you.

Attacks Affected: You have Advantage on attack rolls against that creature and attacks against you from that creature are made at Disadvantage.

Surprise: When combat begins, any enemies that you are Unseen to have Disadvantage on their Initiative Rolls. If you are Unseen to all enemies when combat starts, you also have Advantage on the Initiative Roll.

Moving While Unseen: Being Unseen does not require you to remain stationary. It is possible to move out from behind cover or obscurement and remain Unseen. See below.

You cease being Unseen to a creature if any of the following occur: you choose to stop being Unseen and the creature can reasonably perceive you, you make an attack roll against that creature (when the attack hits or misses), you cast a spell with a Verbal component, you make a sound louder than a whisper, an effect explicitly reveals your location, the creature successfully finds you using the Search action, your turn ends while you lack Total Cover, Three-Quarters Cover, or Heavy Obscurement from that creature, or the creature's Passive Perception equals or exceeds your Hide DC while you are outside of Total Cover, Three-Quarters Cover, or Heavy Obscurement.

A creature can cease to be Unseen to one creature without ceasing to be Unseen to others.

Hide [Action]

With the Hide action, you try to conceal yourself. To do so, you must succeed on a DC 15 Dexterity (Stealth) check while you’re Heavily Obscured or behind Three-Quarters Cover or Total Cover to at least one perceived enemy.

On a successful check, you have the Unseen Condition to all creatures for which the prerequisites of taking the Action apply. Make note of your check’s total, which is the DC for a creature to find you with a Wisdom (Perception) check.

A creature cannot use the Search Action to locate you if you are behind Total Cover relative to that creature.

 
Now, I'd like to reduce the amount of words, if possible, and I think I can do so in the "ways to end Unseen" part (and I'm not sure if the Moving While Unseen bit is necessary), but I'm also struggling a bit with Surprise and whether I want things like casting a spell behind total cover to end Unseen or not. Thoughts?

I'm not sure if "concealed" gives the right connotation for the condition itself, but I'll think on it.

As for Passive Perception, I do mention it, but only as a way of avoiding someone actually sneaking up on you during their turn while out of cover.

I'm trying to thread the needle by allowing rogues to use one of their defining fantasies while also not allowing it to be a resourceless Invisibility spell.

I would probably start by cleaning up various terminology

Entity

For convenience, I will refer to creatures, objects, spell effects, terrain features, and other types of effects as entities, just meaning it's something potentially visible that has a location.

Unseen

An unseen entity is a entity that can not or has not been seen. An entity can be unseen by one observer and not by another. This means

• Attacks against an unseen entity are made with disadvantage.
• Attacks by an unseen entity are made with advantage.
• An ability that requires seeing its target does not work on an unseen entity.
• An unseen creature is potentially able to gain surprise.
• An entity is no longer unseen when it has been seen.

Unheard

An unheard entity is an entity that can not or has not been heard. 

• An entity that is unseen cannot have its location determined by hearing. It can still be determined in other ways, including sight.

Blind

A blind creature cannot see with with normal vision, darkvision, or truesight, potentially rendering other entities Unseen.

Concealment

Concealment is the visual equivalent of cover -- cover blocks line of effect, while concealment blocks line of sight. Most concealment affects normal vision, darkvision, and truesight, but not blindsight. An entity that has full cover cannot be seen with affected senses, potentially rendering it Unseen. A creature can have concealment from only some locations or angles.

Darkness

Entities in an area of darkness cannot be seen with normal vision, potentially rendering them Unseen.

Heavily Obscured

Entities in a heavily obscured area cannot be seen with normal vision, darkvision, or truesight, potentially rendering them Unseen. See also Opaque.

Hidden

A hidden entity is difficult to see, requiring a skill check with normal vision or darkvision. A creature can be hidden from only some locations or angles.

Invisible

An invisible creature cannot be seen with normal vision or darkvision, potentially rendering it Unseen.

Opaque

An opaque effect blocks normal vision, darkvision, and truesight into, out of, or through it. An entity inside an opaque effect is Blinded and Heavily Obscured; entities outside of the effect may gain Concealment.

Quote from Pantagruel666 >>

I would probably start by cleaning up various terminology

Entity

For convenience, I will refer to creatures, objects, spell effects, terrain features, and other types of effects as entities, just meaning it's something potentially visible that has a location.

Unseen

An unseen entity is a entity that can not or has not been seen. An entity can be unseen by one observer and not by another. This means

• Attacks against an unseen entity are made with disadvantage.
• Attacks by an unseen entity are made with advantage.
• An ability that requires seeing its target does not work on an unseen entity.
• An unseen creature is potentially able to gain surprise.
• An entity is no longer unseen when it has been seen.

Unheard

An unheard entity is an entity that can not or has not been heard. 

• An entity that is unseen cannot have its location determined by hearing. It can still be determined in other ways, including sight.

Blind

A blind creature cannot see with with normal vision, darkvision, or truesight, potentially rendering other entities Unseen.

Concealment

Concealment is the visual equivalent of cover -- cover blocks line of effect, while concealment blocks line of sight. Most concealment affects normal vision, darkvision, and truesight, but not blindsight. An entity that has full cover cannot be seen with affected senses, potentially rendering it Unseen. A creature can have concealment from only some locations or angles.

Darkness

Entities in an area of darkness cannot be seen with normal vision, potentially rendering them Unseen.

Heavily Obscured

Entities in a heavily obscured area cannot be seen with normal vision, darkvision, or truesight, potentially rendering them Unseen. See also Opaque.

Hidden

A hidden entity is difficult to see, requiring a skill check with normal vision or darkvision. A creature can be hidden from only some locations or angles.

Invisible

An invisible creature cannot be seen with normal vision or darkvision, potentially rendering it Unseen.

Opaque

An opaque effect blocks normal vision, darkvision, and truesight into, out of, or through it. An entity inside an opaque effect is Blinded and Heavily Obscured; entities outside of the effect may gain Concealment.

 

Ah, I like this. It's basically everything I was thinking. Specifically, I think the distinction between Concealment and Cover is incredibly important for the verisimilitude of the game. I was also going to get into darkness (lack of light) and opaque (blocking light) in a different post, but here we are :).

Quote from SunIsGettingRealLow96589 >>

"cover blocks line of effect fire" <-- cover blocks attacks. Increase your AC or make you impossible to hit. Increase your Saving Throw. 

Total cover blocks line of effect, which includes but is not limited to attacks. See spell targets and cover.

Quote from SunIsGettingRealLow96589 >>

Cover is anything that protects you from damage, such as terrain, a stone wall, a large tree. Half Cover: +2 to AC and Dex saves. Theee-Quarter Cover: +5 to AC and Dex saves. Full cover: Cannot be hit by attacks, cannot be damaged by Dex Save effects unless the effect is described as being able to go around corners.

Full cover: can't be targeted. It doesn't just stop damage, it stops everything.

Quote from SunIsGettingRealLow96589 >>

I would need a full definiton of what "targeting" means in dnd.

Targeting means picking a target for an attack, spell, or other ability. Acting as a forward observer for someone else is not targeting in the D&D sense.

Quote from SunIsGettingRealLow96589 >>

Well, it doesnt stop aoe's that say the area goes around corners. 

 That's specific vs general, yes. Also, AoEs have particular rules for tracing cover, in that you care about cover relative to the origin point of the AoE, rather than relative to the caster.

Quote from SunIsGettingRealLow96589 >>

Also, and this is a personal pet peeve, but if a spell says a beam of energy or whatever goes from the caster to the intended target, then id say full cover stops it. But if the spell doesnt mention anything like that, then to me, cover doesnt prevent targeting.

The rules disagree with you.

Quote from SunIsGettingRealLow96589 >>

The idea with these rules is to fix the idiocy that when you are in an dark enclosed cavern, you cant see a torch that is 50 feet away from you because it only throws dim light to 40 feet.

 Unless you're treating darkness as opaque (its own can of worms), that's not true in the first place. To see an object, the location it is in must be lit, there's no requirement that your own location be lit.

I think you might be overestimating the number of DMs that would rule that you can't see the torch from far away. I, for sure, have argued that the opaque language used leans heavily towards that being RAW, but I wouldn't rule it that way in my games.

In fact, I don't hate your solution of adding a range for visibility at all (and I think renaming—did it even have a name to begin with—the light shed to illumination is a good one).

Quote from SunIsGettingRealLow96589 >>

There is a rather large group of players and dms that say, raw you cant see a torch when you are 50 feet away, because it casts bright light 20 feet, dim lin to 40 feet, and it casts no light beyond that. And then they all homebrew something different to fix it.

My idea is to fix the rules for illumination so that raw, this is no longer a problem.

My text fixes this by separating darkness from heavily obscured.

Quote from SunIsGettingRealLow96589 >>

Thats not the source of the problem.

The source of the problem is that the description for a torch says it casts bright light to 20 feet and dim lim light to 40 feet.

Therefore, raw, it casts no light at all beyond 40 feet. Which means you cant see it.

No, RAW says nothing of the sort. You cannot see an object that is in darkness, but the torch isn't in darkness, it's brightly lit, and thus visible. The only RAW limits I'm aware of for how far away you can see an illuminated object are in Perception and Encounters, and are measured in miles.

Quote from SunIsGettingRealLow96589 >>

From the page you linked:

"Visibility Outdoors. When traveling outdoors, most characters can see about 2 miles in any direction on a clear day, "

I didnt see anything there about torches in a pitch black cavern...

 That's correct. There are no published limits, and thus in theory they can be seen at infinite distance. Unless you decide that darkness is opaque, which produces such a wide range of nonsense that everyone decides it isn't.

Quote from SunIsGettingRealLow96589 >>

"There are no published limits, and thus in theory they can be seen at infinite distance."

But "in theory" isnt the same as "written".

 As written, there are no limits and thus the DM decides appropriate limits. The realistic distance at which a light source is visible is extremely situational (it depends on just how dark the darkness actually is, and on things such as whether you're carrying a light source) and also sufficiently large to make the discussion pointless -- in total darkness, under good conditions, a candleflame is visible at a distance of several miles.

I don't think we need to relitigate the discussion of whether RAW darkness is opaque or not here ;).

You've both given me some things to mull over, though. I'll have to rewrite up those thoughts to see them all together to check of coherence, but thank you for the discussion.

Quote from SunIsGettingRealLow96589 >>

Hm.... if you just say that a light source is visible 10 times the distance it casts dim light, then you dont even have to update the equipment list, and the math is easy to do in your head.

 Nothing else in the game says in general how far away it can be seen, why should light sources be different? And a mere 10x is absurdly short.

As a side note, if I may, I had brought up the idea of giving a PC the ability to keep advantage if they started the turn hidden a while ago now (many TT wargames do something like this), and I think I got a response that it would be too abusable. I'm not sure I agree, but I'm also unsure how that would interact with my take on Invisibility. Thoughts on that aspect of my homebrew?

To summarize, a hidden creature uses it's Hide Score as a DC for passive perception to notice them sneaking up on them during the turn they leave cover to attack in melee.

I see where you are coming from, but I WANT an assassin trope character to be able to at least move their movement—with a high enough hide roll—and make their first attack with advantage. I don't like limiting the melee assassin to ranged attacks.

I was told this might be OP, but without playtesting, I can't say I agree. 

Quote from SunIsGettingRealLow96589 >>

To keep the terminology as close to what players are used to,  i would change Unseen Conditon to  the Hidden Condition to reflect my evolving thoughts on this thread.

Someone who's in the middle of a cloud of opaque smoke is unseen (enemies can't see them) but not hidden (they have made no special effort to actually hide).

Quote from SunIsGettingRealLow96589 >>

I dont think fully obscured or full cover need to be conditions, they can just be modifiers younuse in certsin cases. 

 Being unseen is not a condition. It just means that you qualify for the rules in "unseen attackers and targets". Being hidden is a reason you're unseen.