Cone Areas (3.5)

[SirNibbles]

The purpose of this thread is to look at both the Rules and Written and the intent behind the functions of cone-shaped effects and how they are affected by abilities which alter shape, size, and range. This is intended to explore all cone effects, not just spells.

"Cone: A cone-shaped spell shoots away from you in a quarter-circle in the direction you designate. It starts from any corner of your square and widens out as it goes. Most cones are either bursts or emanations (see above), and thus won’t go around corners." - Rules Compendium, page 135

"Cover and Reflex Saves
Cover grants you a +2 bonus on Reflex saves against attacks that originate or burst out from a point on the other side of the cover from you. Note that spread effects can extend around corners and thus negate this cover bonus." - SRD

"Soft Cover
Creatures, even your enemies, can provide you with cover against ranged attacks, giving you a +4 bonus to AC. However, such soft cover provides no bonus on Reflex saves, nor does soft cover allow you to make a Hide check." - SRD

"An otherwise solid barrier with a hole of at least 1 square foot through it doesn’t block a spell’s line of effect. Such an opening means that the 5-foot length of wall containing the hole is no longer considered a barrier for the purpose of a spell’s line of effect." - Rules Compendium, page 80

"Burst
A burst spell affects whatever it catches in its area, even including creatures that you can’t see. It can’t affect creatures that have total cover from its point of origin...A burst’s size defines how far from the point of origin the spell’s effect extends." - Rules Compendium, page 135

It seems quite clear-cut as to how creatures/objects within the area of a cone are hit.
1. Choose the starting point and the direction.
2. The cone extends to the limit of the range, hitting everything within line of effect. Its shape is a quarter circle. If the effect allows a reflex save, hard cover grants a +2. Soft cover, such as a creature, does not grant this reflex save bonus. Unless the cone is specifically identified as a spread, it is stopped by total cover.

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Firstly, I'd like to examine the effect of range-improving effects on cones. Some people claim that by RAW, simply increasing the range of a cone effect does not work.


...because this is only adding range, so can't change the cone. It's a one dimensional interaction with a three dimensional shape.

I disagree. Based on the fact that the cone's area is defined by how far from the point of origin the spell extends and it widens as it goes, forming a quarter circle (see above quotes), increasing the range of a cone therefore increases the area affected. However, the easiest way of increasing a spell's range, Enlarge Spell, does not work.

"Spells whose ranges are not defined by distance, as well as spells whose ranges are not close, medium, or long, do not have increased ranges." - Enlarge Spell; Player's Handbook, page 94

For breath weapon cones, the Enlarge Breath feat (Draconomicon, page 70) specifically states that because it's increasing the range of the breath weapon, the cone gets wider at the end. It's not the best evidence for it working like that across the board, but it's all I've got.

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Next, let's look at how increasing the area affects a cone, for example with Widen Spell.

"You can alter a burst, emanation, line, or spread shaped spell to increase its area. Any numeric measurements of the spell’s area increase by 100%. For example, a fireball spell (which normally
produces a 20-foot-radius spread) that is widened now fills a 40-foot radius spread." - Player's Handbook, page 102

I think the way this works is open to more interpretation than increasing the range. The given example of increasing a 20 foot radius spread (sphere) to 40 feet results in the 2D area increasing by 300% (quadrupling). The volume increases 8x. Thus, it may not be as simple as saying 'you affect twice as many squares'. One issue with Widen Spell for cones is the fact that the spell's range remains unchanged which results in the increased area having to fit somewhere in the original range.

"A spell’s range is the maximum distance from you at which the spell’s effect can occur, as well as the maximum distance at which you can designate the spell’s point of origin. If any portion of the spell’s area would extend beyond this point, that area is wasted." - Rules Compendium, page 126

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The volume of a cone is 1/3πr3h. However, what if I told you the shape formed by a D&D cone isn’t necessarily equal to an actual cone?

This is a cone.

https://www.web-formulas.com/displayImage.aspx?imageid=436

In D&D, the range of the cone is l, not h. However, nor is the shape formed is actually exactly one eighth of a sphere. Instead, it's a spherical sector.

https://upload.wikimedia.org/wikipedia/commons/thumb/e/e0/Kugel-sektor.png/800px-Kugel-sektor.png

The volume of a spherical sector, and thus a D&D cone = (2/3)πr3h.

Here's a spherical sector with 90 degree angles, i.e. the way a D&D cone is. Note that in order to get the max ground coverage, half the cone is underground (wasted).

https://i.imgur.com/K3fPRnH.png

Anyhow, back to the main point. How exactly do you increase "any numeric measurements of the spell's area by 100%"? Do you double r? If you do, the range is unchanged and literally all of the increase is wasted.

https://i.imgur.com/JPK1XjR.png

One option would be to change it from a quarter circle (90 degrees) to a half circle (180 degrees). The 3D cone becomes a hemisphere with the range remaining the same. The area actually does only double in this case. The volume, at a guess, becomes 4x normal.

Another option is to interpret "any numeric measurements of the spell's area" as including the range. I've not been able to find any more official sources regarding the matter and the sources I've posted above can be ruled on either way. Shockingly, in this rare case, WOTC managed to make a rule that was difficult to understand.

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Conclusions: By RAW, anything that increases the range of any cone will cause the area to increase, due to the way conical areas are defined. Enlarge Spell does not work for cones that do not have a range of Close, Medium, or Long (which is all cones as far as I know). Widen Spell may or may not work for cones in one or more ways.

[DrMotives]

Prerequisites: Con 13, breath weapon.
Benefit: The length of your breath weapon increases by
50% (round down to the nearest multiple of 5). For example,
an old silver dragon breathing an enlarged cone of cold produces
a 75-foot cone instead of a 50-foot cone. Cone-shaped
breath weapons get wider when they get longer, but line-shaped
breath weapons do not.

I think your point about Enlarge not increasing the length of a cone is incorrect.

[SirNibbles]

I think your point about Enlarge not increasing the length of a cone is incorrect.

I said that it did increase the length, thus it works in three dimensions, contrary to what some people were saying about cone-lengthening.

[Karl Aegis]

Wait, a D&D cone isn't a real cone. It's a quarter-circle. It doesn't cover a volume, it covers an area. What are these spheres and how do they relate to the quarter-circle?

[HouseRules]

In 3E, Volume are measure in Square Prism.
Each Prism is 5 feet x 5 feet x 10 feet.
When half of the space is covered, it is in the effect of a spell.
Remember that height are only in multiples of 10 feet, just like distance is only in multiples of 5 feet.

[SirNibbles]

Wait, a D&D cone isn't a real cone. It's a quarter-circle. It doesn't cover a volume, it covers an area. What are these spheres and how do they relate to the quarter-circle?

If you look at the image of the spherical sector, you will see that its cross-section forms a quarter circle. I was under the impression that things in D&D occur in three dimensions but are usually simplified down to two because that's good enough for most situations. Do cones actually spread out completely flat? Are spherical bursts actually just circles?


In 3E, Volume are measure in Square Prism.
Each Prism is 5 feet x 5 feet x 10 feet.
When half of the space is covered, it is in the effect of a spell.
Remember that height are only in multiples of 10 feet, just like distance is only in multiples of 5 feet.

Source? Only things I could find regarding that subject:

"When determining whether a given creature is within the area of a spell, count out the distance from the point of origin in squares, counting from grid intersection to grid intersection. You can count diagonally across a square, but every second diagonal counts as 2 squares of distance. If the far edge of a square is within a spell’s area, anything within that square is within the spell’s area. If a spell’s area touches only the near edge of a square, however, anything within that square is unaffected by the spell." - Rules Compendium, page 135

"Shapeable Spells
If an Area or Effect entry ends with “(S),” you can shape the spell. A shaped effect or area can have no dimension smaller than 10 feet. Many effects or areas are given as cubes to make it easy to model irregular shapes. Three-dimensional volumes are most often needed to define aerial or underwater effects and areas." - Rules Compendium, page 136

[Karl Aegis]

Take out your cone template and tell me that isn't flat.

[DarkSoul]

Widen spell affects bursts and emanations. Most cones are described as bursts or emanations according to the rules compendium. It seems pretty cut-and-dried to me.

[SirNibbles]

Take out your cone template and tell me that isn't flat.

#000FFF for blue text if you're on mobile


Widen spell affects bursts and emanations. Most cones are described as bursts or emanations according to the rules compendium. It seems pretty cut-and-dried to me.

That doesn't change the fact that a spell can't function outside the max range of said spell. Therefore, in order for it to get bigger, the range must increase or the shape of the cone must change and become wider.

[ExLibrisMortis]

Widen spell affects bursts and emanations. Most cones are described as bursts or emanations according to the rules compendium. It seems pretty cut-and-dried to me.
You completely missed all the points in the OP to confirm something that wasn't even contested >.>.


I agree that Enlarge Spell should work on a cone spell, since the cone gets its range from the spell's Range entry.


Widen Spell is says "numeric measurements of the spell’s area increase by 100%". Most spells have their area given by a combination of radius + shape, of which the radius is numeric, and the shape is not; Widen Spell only affects the former (that's just as well, since it's hard to see how it could affect the latter) and so is compatible with cones.

To avoid the "area wasted due to range limit", you might rule that since the spell's "numeric measurement of its area" is given by its range, Widen Spell must increase the range by 100%. I'm not calling it RAW, but it's a reasonable fix. Spells that have a separate measurement of area and range (such as fireball) wouldn't be affected, but cones could be successfully Widened (and even Enlarge-Widened, which should be good for all those blaster sorcs with army-wasting aspirations).

[Troacctid]

Sooooo...


At 2nd level, an arcane archer gains the ability to place an area spell upon an arrow. When the arrow is fired, the spell’s area is centered on where the arrow lands, even if the spell could normally be centered only on the caster. This ability allows the archer to use the bow’s range rather than the spell’s range. It takes a standard action to cast the spell and fire the arrow. The arrow must be fired in the round the spell is cast, or the spell is wasted.

...that's a big cone, guys.

EDIT: A composite greatbow has a range increment of 130 feet. Add the distance property and the Far Shot feat, and that's a 3800-ft. cone, or about three-quarters of a mile. Seems dece.

[Anthrowhale]

The use of Arcane Archer cones for battlefield scale effects is certainly dramatic....

Presumably Sculpt Spell[Cone] + Widen Spell is also potentially useful since the Sculpt Spell cone is not normally limited to 40' instead of range.

[ExLibrisMortis]

Sooooo...

...that's a big cone, guys.

EDIT: A composite greatbow has a range increment of 130 feet. Add the distance property and the Far Shot feat, and that's a 3800-ft. cone, or about three-quarters of a mile. Seems dece.
That's a really nice find. So you just want to fire the arrow to the square in front of you, and enjoy maximum destruction :smallbiggrin:.

[weckar]

I think we've just hit the deep end, and the water is great.

Let's not go off it.

[SirNibbles]

That's a really nice find. So you just want to fire the arrow to the square in front of you, and enjoy maximum destruction :smallbiggrin:.

By strict (idiotic) RAW that's not 100% correct.

"the spell’s area is centered on where the arrow lands, even if the spell could normally be centered only on the caster. This ability allows the archer to use the bow’s range rather than the spell’s range." - Arcane Archer: SRD

Firstly, the fact that the cone has to go away from you isn't changed by the Arcane Archer's ability. Second, the spell has to be centred on, not originating from, where the arrow lands. What's the centre of the cross-section of a spherical sector, i.e. the centroid of a quarter circle?

It's sqrt(16r2/(9π2)) away from the point of the cone. Thus, with the max range of the arrow being 3800 feet, in order for it to actually fill that entire space, you would need to have the arrow land 1613 feet away. Simplified, you need to hit at 42.4% of the max range.

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If only breath weapons and spit cones had more ways of being enlarged. Spellcasters seem to get all the nice things.

[Troacctid]

By strict (idiotic) RAW that's not 100% correct.

"the spell’s area is centered on where the arrow lands, even if the spell could normally be centered only on the caster. This ability allows the archer to use the bow’s range rather than the spell’s range." - Arcane Archer: SRD

Firstly, the fact that the cone has to go away from you isn't changed by the Arcane Archer's ability. Second, the spell has to be centred on, not originating from, where the arrow lands. What's the centre of the cross-section of a spherical sector, i.e. the centroid of a quarter circle?

It's sqrt(16r2/(9π2)) away from the point of the cone. Thus, with the max range of the arrow being 3800 feet, in order for it to actually fill that entire space, you would need to have the arrow land 1613 feet away. Simplified, you need to hit at 42.4% of the max range.

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If only breath weapons and spit cones had more ways of being enlarged. Spellcasters seem to get all the nice things.
Under that reading, the cone you get for firing the arrow at your feet is still the biggest possible, because now it extends in both directions.

I think it's more plausible that "centered" in the case of a cone is either the axis of the cone, in which case it still originates from you and the arrow basically determines direction; or the center of the circle before quartering it, in which case the arrow becomes the origin point.

[SirNibbles]

Under that reading, the cone you get for firing the arrow at your feet is still the biggest possible, because now it extends in both directions.

I think it's more plausible that "centered" in the case of a cone is either the axis of the cone, in which case it still originates from you and the arrow basically determines direction; or the center of the circle before quartering it, in which case the arrow becomes the origin point.

But that's not what arcane archer says and WOTC would never make an ability which is completely broken in terms of both power and rules ambiguity.

Yeah, they probably mean origin rather than centre. It'd be weird for line spells as well if it worked that way. Either way, it's broken as written.

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As for Sculpt Spell, I don't think it works with the Arcane Archer cheese because it doesn't change the spell to 'Area: Cone-shaped burst'; it changes it to 'Area: 40-foot Cone-shape'. That means it would be limited to 40 feet rather than the limit of the spell's range as for a normal cone. Then again, Sculpt Spell isn't written too well either, automatically making any spherical AoE a spread, when we know spherical bursts exist and are quite common.

[daremetoidareyo]

If you glyph of warding on your spell list and sculpt(cone) enlarged it, could you buff a whole army?

[Karl Aegis]

#000FFF for blue text if you're on mobile


Why would I need to use blue text when I'm telling you to use the tool players actually used in tournament/competitive play? It's sound advice.

[weckar]

Also, remember that blue text is not a rule - just an annoying habit.

[Segev]

Why would I need to use blue text when I'm telling you to use the tool players actually used in tournament/competitive play? It's sound advice.

Because it's not sound advice when the template is a 2D slice of a 3D object. Or are you suggesting that walls are actually just lines on the ground and it's just politeness that keeps PCs from stepping over them?

[Karl Aegis]

Because it's not sound advice when the template is a 2D slice of a 3D object. Or are you suggesting that walls are actually just lines on the ground and it's just politeness that keeps PCs from stepping over them?

I highly doubt a referee would allow you to go through a piece of terrain without a specific ability that allows you to bypass it like the young black dragon's ability to fly.

[Segev]

I highly doubt a referee would allow you to go through a piece of terrain without a specific ability that allows you to bypass it like the young black dragon's ability to fly.

And I highly doubt that ref would allow you to say that you’re standing 10 ft. above the template of a fireball or cone of cold and thus out of its AoE even though it’s 30 ft. wide where you are.

[Karl Aegis]

And I highly doubt that ref would allow you to say that you’re standing 10 ft. above the template of a fireball or cone of cold and thus out of its AoE even though it’s 30 ft. wide where you are.

If you're out of range, you're out of range. Your opponent should learn to position better.

[SirNibbles]

Why would I need to use blue text when I'm telling you to use the tool players actually used in tournament/competitive play? It's sound advice.

Are you seriously suggesting cones and spheres are flat because the templates are flat or is this a very committed joke?

The templates are two dimensional because that is all you need most of the time and it's easier that way. The height of the cone is always half of the distance from the origin so there's no need to have a 3D template except for the first edge of the cone.

[Karl Aegis]

Are you seriously suggesting cones and spheres are flat because the templates are flat or is this a very committed joke?

The templates are two dimensional because that is all you need most of the time and it's easier that way. The height of the cone is always half of the distance from the origin so there's no need to have a 3D template except for the first edge of the cone.

"Cone: A cone-shaped spell shoots away from you in a quarter-circle in the direction you designate. It starts from any corner of your square and widens out as it goes. Most cones are either bursts or emanations (see above), and thus won’t go around corners." - Rules Compendium, page 135

It's a quarter-circle. Quarter-circles are not three-dimensional objects.

[Segev]

"Cone: A cone-shaped spell shoots away from you in a quarter-circle in the direction you designate. It starts from any corner of your square and widens out as it goes. Most cones are either bursts or emanations (see above), and thus won’t go around corners." - Rules Compendium, page 135

It's a quarter-circle. Quarter-circles are not three-dimensional objects.

And this is why reflex saves always are for 0 damage against cones, because you can just duck under or jump over them, as they're two-dimensional objects!

Since you seem to be being serious, I'm just going to have to say, "No, you're wrong," because at this point, trying to argue with you is going to be like trying to argue that relativity is a thing with somebody who insists as a premise that Newtonian mechanics are a perfect model of the world.

[Karl Aegis]

And this is why reflex saves always are for 0 damage against cones, because you can just duck under or jump over them, as they're two-dimensional objects!

Since you seem to be being serious, I'm just going to have to say, "No, you're wrong," because at this point, trying to argue with you is going to be like trying to argue that relativity is a thing with somebody who insists as a premise that Newtonian mechanics are a perfect model of the world.

Well, it's a quote from the OP. If the OP is wrong then this whole thread seems kind of pointless. Does anyone have any evidence a cone area of effect is actually cone-shaped, not the quarter-circle the rules say it is?

[weckar]

I actually need to agree with Karl. By game rules (not realism or simulation) a cone is flat.

[Troacctid]

It does quite clearly say it's a "cone." Do we need the game to define "cube" and "circle" too?

[ExLibrisMortis]

I agree with Troacctid on this one. "Cone" just means cone.

For draconic breath weapons, it is specified that "a cone is as wide and high as its length". You might consider this the general rule, but its presence in the true dragon section of the Monster Manual suggests otherwise. The Rules Compendium and DMG seem to assume it's flat, too.

[Troacctid]

For draconic breath weapons, it is specified that "a cone is as wide and high as its length". You might consider this the general rule, but its presence in the true dragon section of the Monster Manual suggests otherwise.
It's a useful reminder in that section because dragons will often use their breath weapon from above their targets, which means the usual templates don't work.

[zergling.exe]

It does quite clearly say it's a "cone." Do we need the game to define "cube" and "circle" too?


I agree with Troacctid on this one. "Cone" just means cone.

For draconic breath weapons, it is specified that "a cone is as wide and high as its length". You might consider this the general rule, but its presence in the true dragon section of the Monster Manual suggests otherwise. The Rules Compendium and DMG seem to assume it's flat, too.

By strict RAW, Karl is right. The rules for cones specify that they are a quarter circle, so despite the shape being called a "cone", cone areas don't hit anything above or below the plane they are used on. Dragon breath weapons would be an explicit exception to the general rule. No this is not how I'd rule in a game, just what the rules actually say.

[Segev]

By strict RAW, Karl is right. The rules for cones specify that they are a quarter circle, so despite the shape being called a "cone", cone areas don't hit anything above or below the plane they are used on. Dragon breath weapons would be an explicit exception to the general rule. No this is not how I'd rule in a game, just what the rules actually say.

By his logic, too, since the templates never bisect any minis, nobody is ever hit by a "cone."

[Karl Aegis]

By his logic, too, since the templates never bisect any minis, nobody is ever hit by a "cone."

Get a sharper template.

[GrayDeath]

Get a sharper template.

But then they bisect your fingers, this is not a desired outcome either. ^^

[weckar]

By his logic, too, since the templates never bisect any minis, nobody is ever hit by a "cone."Because minis - Like templates - are a representation of the game state and not the game state itself. And I believe you know this full well.

[Segev]

Because minis - Like templates - are a representation of the game state and not the game state itself. And I believe you know this full well.

It is, in fact, my point. Just as the minis don't have to literally have the template bisect them, the template is a 2d conic section of a 3d cone. As is the planar representation of things illustrated and discussed in the PHB where it talks about "quarter-circles." It's dealing with the 2d representation of the game state, and uses appropriate language to that. It does not mean that the cone itself is 2d. Heck, it goes on to describe cones in such a way that "quarter-circle" is entirely inaccurate, since they actualy form triangles when bisected in the middle in 2d space. If they were quarter-circles, their ends would be rounded, not flattened.

In other words, the intent is clear as long as you don't try to read so much into it that the argument about templates being flat means that they also never affect any minis since they don't actually pass through the minis.

[zergling.exe]

It is, in fact, my point. Just as the minis don't have to literally have the template bisect them, the template is a 2d conic section of a 3d cone. As is the planar representation of things illustrated and discussed in the PHB where it talks about "quarter-circles." It's dealing with the 2d representation of the game state, and uses appropriate language to that. It does not mean that the cone itself is 2d. Heck, it goes on to describe cones in such a way that "quarter-circle" is entirely inaccurate, since they actualy form triangles when bisected in the middle in 2d space. If they were quarter-circles, their ends would be rounded, not flattened.

In other words, the intent is clear as long as you don't try to read so much into it that the argument about templates being flat means that they also never affect any minis since they don't actually pass through the minis.

So let me get this straight, you're saying that cone AoEs have a flattened end correct? In 3.5 that is explicitly wrong, unsure about PF though but this is a 3.5 thread. In 3.5 the templates clearly show a rounded edge if you look in the DMG on page 306. That would be a quarter-circle (or a cross-section of a sphere, but the rules tell us quarter-circle), NOT a cross-section of a cone.

[Yael]

Giant in the Playground, where cone-shaped Breath Weapons are found 16 years later to actually be beatable by 5 ranks in Jump. :smallredface:

[weckar]

Dragon's breath weapons are specifically called out to have height, though.

[Segev]

So let me get this straight, you're saying that cone AoEs have a flattened end correct? In 3.5 that is explicitly wrong, unsure about PF though but this is a 3.5 thread. In 3.5 the templates clearly show a rounded edge if you look in the DMG on page 306. That would be a quarter-circle (or a cross-section of a sphere, but the rules tell us quarter-circle), NOT a cross-section of a cone.

Do they? I wonder where I saw the flattened end, then. Ah well! This is superior, anyway.

[PhoenixPhyre]

Do they? I wonder where I saw the flattened end, then. Ah well! This is superior, anyway.

Probably 5e, where cones are true cones (not sections of a circle).

One other edition-related oddity--do I understand correctly that a 3e cone is a 90-degree (1/4 circle) effect? 5e's are not. They're defined so that at distance d, the width of the effect is also d. This means that the "range" is the height of the cone and at max extent, a 30' cone hits things 15' on either side of that centerline (which is not a 90-degree angle at all, being only 53.13 degrees in central angle).

[zergling.exe]

Probably 5e, where cones are true cones (not sections of a circle).

One other edition-related oddity--do I understand correctly that a 3e cone is a 90-degree (1/4 circle) effect? 5e's are not. They're defined so that at distance d, the width of the effect is also d. This means that the "range" is the height of the cone and at max extent, a 30' cone hits things 15' on either side of that centerline (which is not a 90-degree angle at all, being only 53.13 degrees in central angle).

This is how a dragon's breath weapon works, but all other 3.5 cones to my knowledge use the PHB definition stating they are a quarter-circle, and so don't have vertical dimensions.

[PhoenixPhyre]

This is how a dragon's breath weapon works, but all other 3.5 cones to my knowledge use the PHB definition stating they are a quarter-circle, and so don't have vertical dimensions.

Which is totally screwy and nothing like a cone. I'd always figured it was better than that, but :shrug:. If I ever played 3.5, I'd immediately say that they're a 90-degree solid-angle section of a sphere (ie 1/8th of a sphere).

[Karl Aegis]

You can rotate your cone template so it hits your target if they jump. Nowhere does it state that the quarter-circle has to be flat. Dragon's breath even rotate's the template 360 degrees! If it hits you as it spins, you're toast!

[Segev]

Even in the world of the RAW, context is important. It takes deliberately ignoring context and pretending that an argument about the shape of a template meant to project something onto a 2D battlemat being a perfect representation of the shape of the effect in 3D space is in any way not laughable to argue that the PHB actually means that it's a 2D quarter-circle, and not that the PHB is talking about the projection on the 2D battlefield that the rules involving "squares" and other similar references discuss.