In addition to not having to find an area of Darkness to lurk in, one of the nice benefits of casting Darkness on yourself (an object that you pick up and carry with you) is that you don't have to worry about your enemy having Darkvision. You'll know that even if he has Darkvision he wouldn't be able to see you while you are within this area because the Darkness spell description doesn't allow it.
If I have normal senses and I am located within magical Darkness and he has Darkvision and he is located outside of the magical Darkness, we would both be able to see him and yet neither of us would be able to see me because neither of us can "see through" the magical Darkness when trying to see something within the magical Darkness.
I doubt that while in Darkness if you have normal sense you can see throught it but if you have Darkvision can’t see through it. To me it's clear the spell adds Darkvision as a sense that can’t see through it because it can normally see through Darkness, which in no way means that normal vision is meant to see through such opaque Heavily Obscured area.
While in Darkness you're trying to see something there if you're trying to see further outside it and should have the Blinded condition, because vision goes from your eyes out, it's not a top down effect you can pinpoint where to view from. You have to be able to see from where you are to see anywhere else and you can't when Blinded. (Can’t See. You can’t see and automatically fail any ability check that requires sight.
While in Darkness you're trying to see something there if you're trying to see further outside it and should have the Blinded condition, because vision goes from your eyes out, it's not a top down effect you can pinpoint where to view from. You have to be able to see from where you are to see anywhere else and you can't when Blinded. (Can’t See. You can’t see and automatically fail any ability check that requires sight.
This is where you are going wrong. Just because vision goes from your eyes out doesn't mean that that has anything to do with the concept of a Heavily Obscured area. It's the area itself that is obscured, so in this case the effect goes in the opposite direction.
As a loose analogy, consider what happens when you are walking around outside, and you decide to look directly at the sun. Or, perhaps, you are trying to look at an object that is within the sun. Only when you are looking in that particular direction are you Blinded. You are not blinded because of anything having to do with your vision going outward from your eyes -- instead, you are Blinded by the sun that obscures your eyes from being able to see anything on it. Assuming that you didn't actually damage your eyes, the instant that you look in a different direction you are no longer Blinded.
In addition to not having to find an area of Darkness to lurk in, one of the nice benefits of casting Darkness on yourself (an object that you pick up and carry with you) is that you don't have to worry about your enemy having Darkvision. You'll know that even if he has Darkvision he wouldn't be able to see you while you are within this area because the Darkness spell description doesn't allow it.
If I have normal senses and I am located within magical Darkness and he has Darkvision and he is located outside of the magical Darkness, we would both be able to see him and yet neither of us would be able to see me because neither of us can "see through" the magical Darkness when trying to see something within the magical Darkness.
I doubt that while in Darkness if you have normal sense you can see throught it but if you have Darkvision can’t see through it. To me it's clear the spell adds Darkvision as a sense that can’t see through it because it can normally see through Darkness, which in no way means that normal vision is meant to see through such opaque Heavily Obscured area.
You misunderstood my explanation here. These interactions are only relevant when trying to see something in the Heavily Obscured space. So:
Normal Sense looking into a well-lit space: can see
Darkvision looking into a well-lit space: can see
Normal Sense looking into a Dark space: Blinded
Darkvision looking into a Dark space: can see
Normal Sense looking into a Magically Dark space: Blinded
Darkvision looking into a Magically Dark space: Blinded
This is where you are going wrong. Just because vision goes from your eyes out doesn't mean that that has anything to do with the concept of a Heavily Obscured area. It's the area itself that is obscured, so in this case the effect goes in the opposite direction.
Vision has everything to do with Obscured Areas, it's where this rule is found saying effects that obscure vision are explained below
Vision & Light: Some adventuring tasks—such as noticing danger, hitting an enemy, and targeting certain spells—are affected by sight, so effects that obscure vision can hinder you, as explained below.
You misunderstood my explanation here. These interactions are only relevant when trying to see something in the Heavily Obscured space.
Whether that is true depends on which part of the rules you read, and when. There isn't a lot of discussion of how line of sight works, but there are sections that specifically prevent seeing through a heavily obscured space, and I'm not aware of any rules that claim the opposite.
You misunderstood my explanation here. These interactions are only relevant when trying to see something in the Heavily Obscured space.
Whether that is true depends on which part of the rules you read, and when. There isn't a lot of discussion of how line of sight works, but there are sections that specifically prevent seeing through a heavily obscured space, and I'm not aware of any rules that claim the opposite.
Which sections are you referring to? Because there is nothing in the rules for Darkness or the rules for a Heavily Obscured area that prevents seeing through a heavily obscured space at all.
It says heavily obscred area is opaque. It's described as an effect that obscure vision.
You interpret that being in such area doesn't affect your vision but where you try to see instead. I think it's both.
I don't think being in heavily obscured dense foliage don't iobscure vision when being in lightly obscured moderate foliage does.
Light;y Obscured: In a Lightly Obscured area—such as an area with Dim Light, patchy fog, or moderate foliage—you have Disadvantage on Wisdom (Perception) checks that rely on sight.
Which sections are you referring to? Because there is nothing in the rules for Darkness or the rules for a Heavily Obscured area that prevents seeing through a heavily obscured space at all.
The darkness spell clearly specifies that darkvision cannot see through the darkness effect (oddly, it does not say the same for normal sight). Other than that, the only rules for line of sight I know of in the 2014 DMG (line of sight) which do classify 'dense fog' (which is also an example of heavily obscured) as opaque.
If we assume that we're supposed to use common sense and natural language, there are examples of heavily obscurement that are obviously opaque (pretty much everything that isn't darkness) and that are obviously transparent (darkness) so we can't really evaluate the author's intent.
It says heavily obscred area is opaque. It's described as an effect that obscure vision.
You interpret that being in such area doesn't affect your vision but where you try to see instead. I think it's both.
The rule doesn't say that it's both though. Rules only do what they say.
The word "opaque" is defined by the rule as causing the Blindness condition when trying to see something there. You don't use your own definition of opaque. You use the one that's provided by the rule.
When this rule describes the area as being "opaque", that's basically flavor text. it has no mechanical meaning until that term is defined, which happens immediately afterwards in the very next sentence.
Then, when we flip to the Glossary, we see that this first sentence isn't even mentioned. That's because only the second sentence (which is what appears in the Glossary) is mechanically relevant. The Glossary entry even specifies what is meant by "there" . . . it means "in a Heavily Obscured space". It doesn't get any clearer than that. The Glossary entry provides only the information that you actually need to be able to play the game by the rules.
When this rule describes the area as being "opaque", that's basically flavor text. it has no mechanical meaning until that term is defined, which happens immediately afterwards in the very next sentence.
Opaque is not defined in the next sentence; the layout does not indicate that the second sentence is intended as a definition. Opaque is not defined anywhere in the text, which means it has the ordinary language meaning of that word.
It says heavily obscred area is opaque. It's described as an effect that obscure vision.
You interpret that being in such area doesn't affect your vision but where you try to see instead. I think it's both.
The rule doesn't say that it's both though. Rules only do what they say.
The word "opaque" is defined by the rule as causing the Blindness condition when trying to see something there. You don't use your own definition of opaque. You use the one that's provided by the rule.
When this rule describes the area as being "opaque", that's basically flavor text. it has no mechanical meaning until that term is defined, which happens immediately afterwards in the very next sentence.
Then, when we flip to the Glossary, we see that this first sentence isn't even mentioned. That's because only the second sentence (which is what appears in the Glossary) is mechanically relevant. The Glossary entry even specifies what is meant by "there" . . . it means "in a Heavily Obscured space". It doesn't get any clearer than that. The Glossary entry provides only the information that you actually need to be able to play the game by the rules.
And it doesn't say it's one only. The rule is ambiguous: "You have the Blinded condition while trying to see something in a Heavily Obscured space" can mean looking into the area, or it can mean while inside the area. You're instead reading it as: "You have the Blinded condition only while trying to see something that is inside a Heavily Obscured space", which is incorrect because it only applies to one specific situation.
Heavily Obscured is more than just darkness (natural or magical). Someone that's behind dense foliage is Heavily Obscured, and your interpretation means the person in the foliage can't be seen by someone from the outside, but the person inside can see the one in the outside because they're not inside a Heavily Obscured space. Here is where your argument falls apart because by virtue of being in the dense foliage, you also can't see the other person because it is obscuring your vision since it is opaque. A person behind total cover is Heavily Obscured, and cannot be seen by the enemy, but by the same token, Total Cover prevents you from seeing the enemy since it blocks your vision because it opaque, as defined by the book itself.
When this rule describes the area as being "opaque", that's basically flavor text. it has no mechanical meaning until that term is defined, which happens immediately afterwards in the very next sentence.
Opaque is not defined in the next sentence; the layout does not indicate that the second sentence is intended as a definition. Opaque is not defined anywhere in the text, which means it has the ordinary language meaning of that word.
Agreed. The rules do not define what opaque means, so it uses the natural language definition. The second sentence only tells you what condition you gain as a result.
Agreed. The rules do not define what opaque means, so it uses the natural language definition. The second sentence only tells you what condition you gain as a result.
Note that being behind something opaque doesn't actually give you the heavily obscured state, it just means that you might use for the Unseen Attackers and Targets rules (incomprehensibly buried in the cover rules). Which, honestly, makes the rules for being invisible or blinded redundant; it should just say
The darkness spell clearly specifies that darkvision cannot see through the darkness effect (oddly, it does not say the same for normal sight).
No, this is just a reference to what Darkvision can normally do and why this spell is different. Darkvision normally "sees through" Darkness when trying to see something that is in the Darkness (because it can see in Darkness as if it is Dim Light). In Magical Darkness, it cannot do that.
Opaque is not defined in the next sentence; the layout does not indicate that the second sentence is intended as a definition. Opaque is not defined anywhere in the text, which means it has the ordinary language meaning of that word.
I disagree with this very strongly. The first sentence is just flavor text that differentiates this type of area from Lightly Obscured areas, which were being discussed in the previous sentence. It's a transition sentence, helping to flow from one idea to the next. It introduces a new concept. That concept is then fully defined in the sentence that follows it.
The section about Lightly Obscured areas was discussing how you have disadvantage on Perception checks (among other things, that check is to "try to spot things that are obscured . . .") presumably because things are harder than usual to see when they are in such areas. In contrast, a Heavily Obscured area is opaque. [ What does that mean? It means . . .] You have the Blinded condition (see the rules glossary) when trying to see something there.
A big reason why we know this for sure about that first sentence in 2024 is because this rule is highlighted in the Rules Glossary and that entry does not include this first sentence at all. Instead, that entry, in its entirety, reads like this:
Heavily Obscured
You have the Blinded condition while trying to see something in a Heavily Obscured space. See also “Blinded,” “Darkness,” and chapter 1 (“Exploration”).
That's the entire rule according to the Rules Glossary. Those are the mechanically significant parts that are necessary to know in order for you to run your game.
Remember, an "obscured area" obscures an area. It's right there in the name. It doesn't obscure your eyes. It obscures an area.
"You have the Blinded condition while trying to see something in a Heavily Obscured space" . . . can mean while inside the area.
Absolutely no one would write that sentence in that way if that were the intended meaning -- not even a D&D author. Quite obviously, if that were the intent, it would have been written like this:
"You have the Blinded condition while in a Heavily Obscured space."
Or, for the non-Glossary format:
"You have the Blinded condition there."
But that's not what they wrote. They are specifically talking about seeing something that is located in the area. Otherwise, they wouldn't have written all of those words that indicate that.
Heavily Obscured is more than just darkness (natural or magical). Someone that's behind dense foliage is Heavily Obscured, and your interpretation means the person in the foliage can't be seen by someone from the outside, but the person inside can see the one in the outside because they're not inside a Heavily Obscured space.
This is absolutely, positively 100% correct. That is exactly what the rule for Heavily Obscured areas says. Yes.
The next step is to now refer to a completely separate rule: Line of Sight. Mr. Dungeon Master, does this particular dense foliage block Line of Sight? Yes. Yes, it does.
(A few hours later) Ok Mr. Dungeon Master, does this particular Darkness effect block Line of Sight? No. No, it does not.
Total Cover prevents you from seeing the enemy since it blocks your vision because it opaque, as defined by the book itself.
That's not what opaque means -- not within the game and also not in common everyday usage. As far as I can tell that word is never used in any way related to the rules for Cover. Cover can be opaque or translucent.
Another quick example to illustrate what many of you are arguing:
A doctor positions his patient behind a line, facing a poster on a wall that is about 20 feet away.
Doctor: "Ok, it's time for a vision test. Try to read something below Line 7 please."
The patient leaves his position and walks over to the wall just in front of the poster. He turns around and squats down near the floor, up against the wall. He starts looking around the room, puzzled.
Patient: "Ok, I'm below Line 7 . . . what do you want me to read?"
The rule for Heavily Obscured areas is a separate rule and a separate concept from the Line of Sight rule, which in 2014 existed in the DMG and did not list Darkness as an example of something that could block line of sight.
Darkness creates magical darkness that Darkvision can’t see through it, explain how normal vision could?
The specific wording on heavy obscurement specifically says when you are trying to see something in a heavily obscured area you have blinded. Technically looking from the heavily obscured area to an area of complete light doesn't impose any limitations.
But that interpretation doesn’t make any sense. Obviously if you are in a heavily obscured area (such as heavy fog) you can’t see out of it. I know the rule doesn’t specifically state that, but common sense (and real world experience) do.
But that interpretation doesn’t make any sense. Obviously if you are in a heavily obscured area (such as heavy fog) you can’t see out of it. I know the rule doesn’t specifically state that, but common sense (and real world experience) do.
The problem is that darkness and visual cover (bushes, etc) are not the same thing, and 5e is trying to use the same rules for both. You're guaranteed to get nonsensical rules for at least one no matter how you rule.
The rule for Heavily Obscured areas is a separate rule and a separate concept from the Line of Sight rule, which in 2014 existed in the DMG and did not list Darkness as an example of something that could block line of sight.
Darkness creates magical darkness that Darkvision can’t see through it, explain how normal vision could?
The specific wording on heavy obscurement specifically says when you are trying to see something in a heavily obscured area you have blinded. Technically looking from the heavily obscured area to an area of complete light doesn't impose any limitations.
But that interpretation doesn’t make any sense. Obviously if you are in a heavily obscured area (such as heavy fog) you can’t see out of it. I know the rule doesn’t specifically state that, but common sense (and real world experience) do.
This doesn't matter because there is a separate rule for that. The Heavily Obscured area rule is only concerned with the area being obscured. That's the concept of it.
Now, if you want to know whether or not the particular object or effect that causes the area to be Heavily Obscured ALSO blocks your Line of Sight, you have to follow a different rule. In 2014 (and presumably in 2024) that rule is buried in the DMG unfortunately. The 2014 rule reads like this:
L INE OF SIGHT
To precisely determine whether there is line of sight between two spaces, pick a corner of one space and trace an imaginary line from that corner to any part of another space. If at least one such line doesn't pass through or touch an object or effect that blocks vision -- such as a stone wall, a thick curtain, or a dense cloud of fog -- then there is line of sight.
As seen above, whether or not there is Line of Sight depends heavily on the particular object or effect in question.
This is why both dense fog and darkness can create Heavily Obscured areas but only one of them blocks Line of Sight and the other one does not.
Now, if you want to know whether or not the particular object or effect that causes the area to be Heavily Obscured ALSO blocks your Line of Sight, you have to follow a different rule.
No, you don't. "Opaque" means that light (and thus vision) doesn't go through it, and the only spell that creates heavy obscurement that has any text about blocking vision through it is darkness blocking darkvision. The most consistent interpretation of the DMG rules is that all effects that create a heavily obscured area block line of sight.
Now, if you want to know whether or not the particular object or effect that causes the area to be Heavily Obscured ALSO blocks your Line of Sight, you have to follow a different rule.
No, you don't. "Opaque" means that light (and thus vision) doesn't go through it, and the only spell that creates heavy obscurement that has any text about blocking vision through it is darkness blocking darkvision. The most consistent interpretation of the DMG rules is that all effects that create a heavily obscured area block line of sight.
To build on this, the 2014 rules for Heavily Obscured say: "A heavily obscured area—such as darkness, opaque fog, or dense foliage—blocks vision entirely. A creature effectively suffers from the blinded condition when trying to see something in that area."
The 2024 rule changed "blocks vision entirely" to "is opaque", which seems very deliberate and not just for flavor text as it was implied on another post. Oxford defines opaque as "not able to be seen through; not transparent", so the word has the same context as the text from 2014.
The second change in 2024 is the wording went from "something in that area", to "something there" in the exploration section, and on the Glossary to " in a Heavily Obscured area". The wording may have changed, but it effectively means the same as 2014.
The first sentence is just flavor text that differentiates this type of area from Lightly Obscured areas, which were being discussed in the previous sentence. It's a transition sentence, helping to flow from one idea to the next. It introduces a new concept. That concept is then fully defined in the sentence that follows it.
Remember, an "obscured area" obscures an area. It's right there in the name. It doesn't obscure your eyes. It obscures an area.
The first sentence is not just flavor text, it's describing what Obscured Areas are, without it we wouldn't tell what one is.
That's incorrect again, an Obscured Area obcures vision as written under Vision and Light.
Vision and Light
Some adventuring tasks—such as noticing danger, hitting an enemy, and targeting certain spells—are affected by sight, so effects that obscure vision can hinder you, as explained below.
Obscured Areas
An area might be Lightly or Heavily Obscured. In a Lightly Obscured area—such as an area with Dim Light, patchy fog, or moderate foliage—you have Disadvantage on Wisdom (Perception) checks that rely on sight.
A Heavily Obscured area—such as an area with Darkness, heavy fog, or dense foliage—is opaque. You have the Blinded condition (see the rules glossary) when trying to see something there.
Now, if you want to know whether or not the particular object or effect that causes the area to be Heavily Obscured ALSO blocks your Line of Sight, you have to follow a different rule.
No, you don't. "Opaque" means that light (and thus vision) doesn't go through it, and the only spell that creates heavy obscurement that has any text about blocking vision through it is darkness blocking darkvision. The most consistent interpretation of the DMG rules is that all effects that create a heavily obscured area block line of sight.
That is incorrect. In this context, "opaque" actually means either: "You have the Blinded condition (see the rules glossary) when trying to see something there." Or: "You have the Blinded condition while trying to see something in a Heavily Obscured space. See also “Blinded,” “Darkness,” and chapter 1 (“Exploration”)." Those are the only two choices. Whatever else the word might mean elsewhere is irrelevant.
The Darkness spell does not "block" anything. That word is never used. It clarifies that a creature with Darkvision is unable to "see through" the obscurement. Not to be confused with any sort of interruption of Line of Sight.
It simply is not true that all effects that create a heavily obscured area interrupt Line of Sight. They are two different rules which govern two totally different things. The Line of Sight rule discusses objects and effects that actually get in the way of seeing something beyond it. The rules for obscurement discuss whether or not a particular thing can be seen.
Honestly, they may as well have just used the Invisible condition for this rule also because basically a Heavily Obscured area just makes the things that are obscured invisible (with the exception of how Darkvision works). it doesn't actually do anything else mechanically by itself. It just so happens that most (but not all) objects or effects that cause heavy obscurement ALSO block Line of Sight.
One obvious clue is that the lists of examples are different. Examples given for a Heavily Obscured area include: Darkness, heavy fog, or dense foliage. Examples given for objects or effects that interrupt Line of Sight include: stone wall, a thick curtain, or a dense cloud of fog. There is some overlap (dense fog) and there are also some additions (stone wall, thick curtain) and also some very important exclusions (Darkness).
These are two extremely different concepts and require two different rules to adjudicate them.
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I doubt that while in Darkness if you have normal sense you can see throught it but if you have Darkvision can’t see through it. To me it's clear the spell adds Darkvision as a sense that can’t see through it because it can normally see through Darkness, which in no way means that normal vision is meant to see through such opaque Heavily Obscured area.
While in Darkness you're trying to see something there if you're trying to see further outside it and should have the Blinded condition, because vision goes from your eyes out, it's not a top down effect you can pinpoint where to view from. You have to be able to see from where you are to see anywhere else and you can't when Blinded. (Can’t See. You can’t see and automatically fail any ability check that requires sight.
This is where you are going wrong. Just because vision goes from your eyes out doesn't mean that that has anything to do with the concept of a Heavily Obscured area. It's the area itself that is obscured, so in this case the effect goes in the opposite direction.
As a loose analogy, consider what happens when you are walking around outside, and you decide to look directly at the sun. Or, perhaps, you are trying to look at an object that is within the sun. Only when you are looking in that particular direction are you Blinded. You are not blinded because of anything having to do with your vision going outward from your eyes -- instead, you are Blinded by the sun that obscures your eyes from being able to see anything on it. Assuming that you didn't actually damage your eyes, the instant that you look in a different direction you are no longer Blinded.
You misunderstood my explanation here. These interactions are only relevant when trying to see something in the Heavily Obscured space. So:
Normal Sense looking into a well-lit space: can see
Darkvision looking into a well-lit space: can see
Normal Sense looking into a Dark space: Blinded
Darkvision looking into a Dark space: can see
Normal Sense looking into a Magically Dark space: Blinded
Darkvision looking into a Magically Dark space: Blinded
Vision has everything to do with Obscured Areas, it's where this rule is found saying effects that obscure vision are explained below
Whether that is true depends on which part of the rules you read, and when. There isn't a lot of discussion of how line of sight works, but there are sections that specifically prevent seeing through a heavily obscured space, and I'm not aware of any rules that claim the opposite.
Which sections are you referring to? Because there is nothing in the rules for Darkness or the rules for a Heavily Obscured area that prevents seeing through a heavily obscured space at all.
It says heavily obscred area is opaque. It's described as an effect that obscure vision.
You interpret that being in such area doesn't affect your vision but where you try to see instead. I think it's both.
I don't think being in heavily obscured dense foliage don't iobscure vision when being in lightly obscured moderate foliage does.
The darkness spell clearly specifies that darkvision cannot see through the darkness effect (oddly, it does not say the same for normal sight). Other than that, the only rules for line of sight I know of in the 2014 DMG (line of sight) which do classify 'dense fog' (which is also an example of heavily obscured) as opaque.
If we assume that we're supposed to use common sense and natural language, there are examples of heavily obscurement that are obviously opaque (pretty much everything that isn't darkness) and that are obviously transparent (darkness) so we can't really evaluate the author's intent.
The rule doesn't say that it's both though. Rules only do what they say.
The word "opaque" is defined by the rule as causing the Blindness condition when trying to see something there. You don't use your own definition of opaque. You use the one that's provided by the rule.
When this rule describes the area as being "opaque", that's basically flavor text. it has no mechanical meaning until that term is defined, which happens immediately afterwards in the very next sentence.
Then, when we flip to the Glossary, we see that this first sentence isn't even mentioned. That's because only the second sentence (which is what appears in the Glossary) is mechanically relevant. The Glossary entry even specifies what is meant by "there" . . . it means "in a Heavily Obscured space". It doesn't get any clearer than that. The Glossary entry provides only the information that you actually need to be able to play the game by the rules.
Opaque is not defined in the next sentence; the layout does not indicate that the second sentence is intended as a definition. Opaque is not defined anywhere in the text, which means it has the ordinary language meaning of that word.
And it doesn't say it's one only. The rule is ambiguous: "You have the Blinded condition while trying to see something in a Heavily Obscured space" can mean looking into the area, or it can mean while inside the area. You're instead reading it as: "You have the Blinded condition only while trying to see something that is inside a Heavily Obscured space", which is incorrect because it only applies to one specific situation.
Heavily Obscured is more than just darkness (natural or magical). Someone that's behind dense foliage is Heavily Obscured, and your interpretation means the person in the foliage can't be seen by someone from the outside, but the person inside can see the one in the outside because they're not inside a Heavily Obscured space. Here is where your argument falls apart because by virtue of being in the dense foliage, you also can't see the other person because it is obscuring your vision since it is opaque. A person behind total cover is Heavily Obscured, and cannot be seen by the enemy, but by the same token, Total Cover prevents you from seeing the enemy since it blocks your vision because it opaque, as defined by the book itself.
Agreed. The rules do not define what opaque means, so it uses the natural language definition. The second sentence only tells you what condition you gain as a result.
Note that being behind something opaque doesn't actually give you the heavily obscured state, it just means that you might use for the Unseen Attackers and Targets rules (incomprehensibly buried in the cover rules). Which, honestly, makes the rules for being invisible or blinded redundant; it should just say
No, this is just a reference to what Darkvision can normally do and why this spell is different. Darkvision normally "sees through" Darkness when trying to see something that is in the Darkness (because it can see in Darkness as if it is Dim Light). In Magical Darkness, it cannot do that.
I disagree with this very strongly. The first sentence is just flavor text that differentiates this type of area from Lightly Obscured areas, which were being discussed in the previous sentence. It's a transition sentence, helping to flow from one idea to the next. It introduces a new concept. That concept is then fully defined in the sentence that follows it.
The section about Lightly Obscured areas was discussing how you have disadvantage on Perception checks (among other things, that check is to "try to spot things that are obscured . . .") presumably because things are harder than usual to see when they are in such areas. In contrast, a Heavily Obscured area is opaque. [ What does that mean? It means . . .] You have the Blinded condition (see the rules glossary) when trying to see something there.
A big reason why we know this for sure about that first sentence in 2024 is because this rule is highlighted in the Rules Glossary and that entry does not include this first sentence at all. Instead, that entry, in its entirety, reads like this:
That's the entire rule according to the Rules Glossary. Those are the mechanically significant parts that are necessary to know in order for you to run your game.
Remember, an "obscured area" obscures an area. It's right there in the name. It doesn't obscure your eyes. It obscures an area.
Absolutely no one would write that sentence in that way if that were the intended meaning -- not even a D&D author. Quite obviously, if that were the intent, it would have been written like this:
"You have the Blinded condition while in a Heavily Obscured space."
Or, for the non-Glossary format:
"You have the Blinded condition there."
But that's not what they wrote. They are specifically talking about seeing something that is located in the area. Otherwise, they wouldn't have written all of those words that indicate that.
This is absolutely, positively 100% correct. That is exactly what the rule for Heavily Obscured areas says. Yes.
The next step is to now refer to a completely separate rule: Line of Sight. Mr. Dungeon Master, does this particular dense foliage block Line of Sight? Yes. Yes, it does.
(A few hours later) Ok Mr. Dungeon Master, does this particular Darkness effect block Line of Sight? No. No, it does not.
That's not what opaque means -- not within the game and also not in common everyday usage. As far as I can tell that word is never used in any way related to the rules for Cover. Cover can be opaque or translucent.
Another quick example to illustrate what many of you are arguing:
A doctor positions his patient behind a line, facing a poster on a wall that is about 20 feet away.
Doctor: "Ok, it's time for a vision test. Try to read something below Line 7 please."
The patient leaves his position and walks over to the wall just in front of the poster. He turns around and squats down near the floor, up against the wall. He starts looking around the room, puzzled.
Patient: "Ok, I'm below Line 7 . . . what do you want me to read?"
But that interpretation doesn’t make any sense. Obviously if you are in a heavily obscured area (such as heavy fog) you can’t see out of it. I know the rule doesn’t specifically state that, but common sense (and real world experience) do.
The problem is that darkness and visual cover (bushes, etc) are not the same thing, and 5e is trying to use the same rules for both. You're guaranteed to get nonsensical rules for at least one no matter how you rule.
This doesn't matter because there is a separate rule for that. The Heavily Obscured area rule is only concerned with the area being obscured. That's the concept of it.
Now, if you want to know whether or not the particular object or effect that causes the area to be Heavily Obscured ALSO blocks your Line of Sight, you have to follow a different rule. In 2014 (and presumably in 2024) that rule is buried in the DMG unfortunately. The 2014 rule reads like this:
As seen above, whether or not there is Line of Sight depends heavily on the particular object or effect in question.
This is why both dense fog and darkness can create Heavily Obscured areas but only one of them blocks Line of Sight and the other one does not.
No, you don't. "Opaque" means that light (and thus vision) doesn't go through it, and the only spell that creates heavy obscurement that has any text about blocking vision through it is darkness blocking darkvision. The most consistent interpretation of the DMG rules is that all effects that create a heavily obscured area block line of sight.
To build on this, the 2014 rules for Heavily Obscured say: "A heavily obscured area—such as darkness, opaque fog, or dense foliage—blocks vision entirely. A creature effectively suffers from the blinded condition when trying to see something in that area."
The 2024 rule changed "blocks vision entirely" to "is opaque", which seems very deliberate and not just for flavor text as it was implied on another post. Oxford defines opaque as "not able to be seen through; not transparent", so the word has the same context as the text from 2014.
The second change in 2024 is the wording went from "something in that area", to "something there" in the exploration section, and on the Glossary to " in a Heavily Obscured area". The wording may have changed, but it effectively means the same as 2014.
The first sentence is not just flavor text, it's describing what Obscured Areas are, without it we wouldn't tell what one is.
That's incorrect again, an Obscured Area obcures vision as written under Vision and Light.
That is incorrect. In this context, "opaque" actually means either: "You have the Blinded condition (see the rules glossary) when trying to see something there." Or: "You have the Blinded condition while trying to see something in a Heavily Obscured space. See also “Blinded,” “Darkness,” and chapter 1 (“Exploration”)." Those are the only two choices. Whatever else the word might mean elsewhere is irrelevant.
The Darkness spell does not "block" anything. That word is never used. It clarifies that a creature with Darkvision is unable to "see through" the obscurement. Not to be confused with any sort of interruption of Line of Sight.
It simply is not true that all effects that create a heavily obscured area interrupt Line of Sight. They are two different rules which govern two totally different things. The Line of Sight rule discusses objects and effects that actually get in the way of seeing something beyond it. The rules for obscurement discuss whether or not a particular thing can be seen.
Honestly, they may as well have just used the Invisible condition for this rule also because basically a Heavily Obscured area just makes the things that are obscured invisible (with the exception of how Darkvision works). it doesn't actually do anything else mechanically by itself. It just so happens that most (but not all) objects or effects that cause heavy obscurement ALSO block Line of Sight.
One obvious clue is that the lists of examples are different. Examples given for a Heavily Obscured area include: Darkness, heavy fog, or dense foliage. Examples given for objects or effects that interrupt Line of Sight include: stone wall, a thick curtain, or a dense cloud of fog. There is some overlap (dense fog) and there are also some additions (stone wall, thick curtain) and also some very important exclusions (Darkness).
These are two extremely different concepts and require two different rules to adjudicate them.