How wide is a 30' cone at the far end?

[samcifer]

I'm trying to make an area of effect template for aoe spell effects, but I don't know how many 5' squares across it is at the far end opposite from the caster's space on a grid map. I suck at math and appreciate the help. Thanks in advance. :)

[diplomancer]

Something like this

¤¤¤¤¤¤
-¤¤¤¤¤
--¤¤¤¤
---¤¤¤
----¤¤
-----¤
-----C

Where C is the caster, and each symbol is a square. So 6 squares long at the end.

[solidork]

I'm trying to make an area of effect template for aoe spell effects, but I don't know how many 5' squares across it is at the far end opposite from the caster's space on a grid map. I suck at math and appreciate the help. Thanks in advance. :)

The width of the cone is equal to your distance from the starting point. So 5ft away from you it's 5ft wide, 10ft away its 10ft wide.

[samcifer]

Something like this

¤¤¤¤¤¤
-¤¤¤¤¤
--¤¤¤¤
---¤¤¤
----¤¤
-----¤
-----C

Where C is the caster, and each symbol is a square. So 6 squares long at the end.

But I was thinking of on a grid map of one inch squares, each square being a 5' space for size conversion. In that case, wouldn't a 15' cone be 1 square, 3 squares, and 5 five squares at its widest/farthest range? I would think it would be 2 squares wider for every 5 feet (1 square) of distance from the caster, you only increase the width by 1 square for every 5 feet of distance.

[LtPowers]

But I was thinking of on a grid map of one inch squares, each square being a 5' space for size conversion. In that case, wouldn't a 15' cone be 1 square, 3 squares, and 5 five squares at its widest/farthest range? I would think it would be 2 squares wider for every 5 feet (1 square) of distance from the caster, you only increase the width by 1 square for every 5 feet of distance.

No, the rules state that a cone widens by 5' for every 5' of distance from the origin: "A cone’s width at a given point along its length is equal to that point’s distance from the point of origin."

If it's 5 squares wide at 15', that's 25 feet and way too wide.


Powers &8^]

[Tanarii]

AoE templates usually don't map to a grid very well. Just cut it with a point at one end, 6 squares across at the other.

I believe the DMG has the grid rules for partially covered squares.

[Thrudd]

But I was thinking of on a grid map of one inch squares, each square being a 5' space for size conversion. In that case, wouldn't a 15' cone be 1 square, 3 squares, and 5 five squares at its widest/farthest range? I would think it would be 2 squares wider for every 5 feet (1 square) of distance from the caster, you only increase the width by 1 square for every 5 feet of distance.

The cone isn't composed of squares. Cone effects are the same length as they are wide. The template for a 15 ft cone is a triangle shape 15 ft (3") from tip to base and 15ft(3") wide at it's end. You can angle the triangle template any way you want, and any square/model it touches is affected by it.

[diplomancer]

But I was thinking of on a grid map of one inch squares, each square being a 5' space for size conversion. In that case, wouldn't a 15' cone be 1 square, 3 squares, and 5 five squares at its widest/farthest range? I would think it would be 2 squares wider for every 5 feet (1 square) of distance from the caster, you only increase the width by 1 square for every 5 feet of distance.

No, a cone's length is also a cone's diameter at its furthest point, not its radius. So a 15' cone would be:

¤¤¤
-¤¤
--¤
--C

Notice that the number of ¤ is the same as the lines of distance from the caster.

[samcifer]

So a 30' cone reaches 6 5' squares away from the caster and is also 6 square across at the farthest end, while a 60' cone reaches 12 squares and is 12 squares across at the wide end?

[Thrudd]

So a 30' cone reaches 6 5' squares away from the caster and is also 6 square across at the farthest end, while a 60' cone reaches 12 squares and is 12 squares across at the wide end?

yes, exactly

[Dark.Revenant]

30 feet.

.¤¤¤¤¤¤
-¤¤¤¤¤
.-¤¤¤¤
--¤¤¤
.--¤¤
---¤
---C

Doing it strictly, however, doesn't line up with the grids. The AOE-on-grids rule does say, though, that cones partially clipping into a square counts as that whole square being in the AOE. So...

¤¤¤¤¤¤¤
-¤¤¤¤¤
-¤¤¤¤¤
--¤¤¤
--¤¤¤
---¤
---C

Seven squares wide at the end.

[sandmote]

I've put it into an image, to avoid confusion between the listed width at a given distance and the way this appears on a grid. The dark blue line is the actual shape of the cone, and the tiles shaded blue are the areas it effects at 15/30/60 feet (depending on the shade used).

Spoiler: Image

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Please let me know if the formatting is off: I'm aware there's some issue on the forum where an image can appear to the poster but fails to show up for anyone else (including while logged out).

[Tanarii]

I believe the point of origin is supposed to be a corner when it's on a grid? Or is it any point on any edge or corner?

[Dark.Revenant]

I couldn’t find any indication in the books that cone origins would need to be grid-corners. I suppose that’s a way you can play, but it’s not required.

[Thrudd]

You need to be able to aim your spell in any direction, not just in 90 degree angles in line with the grid. You can't make restrictions like only placing it on corners. There's not a lot of utility in making a template out of squares, that's not really the dimensions of the cone, only what it happens to affect when you point it in one particular direction. Just use the properly sized triangle and aim it where you want, and you can figure out what it affects by whatever squares it passes through/models it touches.

[Tanarii]

Found it, DMG 251:
Choose an intersection of squares or hexes as the point of origin of an area of effect, then follow its rules as normal. If an area of effect is circular and covers at least half a square, it affects that square.

It's in the DMG because the PHB rules aren't specifically for battlemats. The rules for battlemats are in the Running The Game chapter in the Combat section.

Nothing says you're supposed to make a template in squares. Just put your point of origin on the intersection, and include any square or hex that has at least 1/2 it's area included.

So in the diagram above, besides using the center of a edge not being correct, there are several squares highlighted that shouldn't be, since they have less than 1/2 a square included.

[sandmote]

Nothing says you're supposed to make a template in squares. Just put your point of origin on the intersection, and include any square or hex that has at least 1/2 it's area included.

Point taken on the intersection bit. Half its area is for circular effects. Straight line effects are covered in Xanathar's, and two differnet methods are given.

From page 86:
To use an area-of-effect template, apply it to the grid. If the terrain is flat, you can lay it on the surface; otherwise, hold the template above the surface and take notes of which squares it covers or partially covers. If any part of a square is under the template that square is included in the area of effect.

People sticking more strongly to the "N feet equals X squares" interpretation appear to be using the Token method.

From page 88:
Starting with a square adjacent to the cone's point of origin, place one token. The square can be orthogonally or diagonally adjacent to the square's point of origin. In every row beyond that one, place as many tokens as you placed in the previous row, plus one more token. Place this row's tokens so that their squares each share a side with a square in the previous row. If the cone is orthogonally adjacent to the point of origin, you'll have one more token to place in the row; place it at one end or the other of the row you just created"

And then it goes on to clarify you can add the left over token (if placing orthogonally) on the side of your choice each time (but in a manner I find awkward to quote).

With the correction about origin point taken, the corrected image for a template method:

Spoiler: Image 2

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[Tanarii]

Interesting. I hadn't realized Xan overrode the DMG rule from 1/2 covered to any part covered. Possibly because otherwise in your diagram you come up with 0 squares in the first row.

Of course, when using a battlemat my method was always eyeball it and give the player the benefit of the doubt.

[Arkhios]

Really it depends on how your table rules diagonal squares.

Some people won't bother with it, but technically if you want to be a "stickler" every diagonal square is 1,5 squares (7,5 ft) (rounded down).

If you wish to make it easier for yourself, you can divide the spell range by 7,5 and you'll get the number of squares needed (just remember, any halves round down to the nearest whole).

So, a 30 ft. is 4 squares away from the origin square diagonally, and 6 squares away from origin square if not.

[Oerlaf]

I'm trying to make an area of effect template for aoe spell effects, but I don't know how many 5' squares across it is at the far end opposite from the caster's space on a grid map. I suck at math and appreciate the help. Thanks in advance. :)

Just use the Xanathar's token rules. It's really convenient and stops people from arguing. At least in my place.

[diplomancer]

Really it depends on how your table rules diagonal squares.

Some people won't bother with it, but technically if you want to be a "stickler" every diagonal square is 1,5 squares (7,5 ft) (rounded down).

If you wish to make it easier for yourself, you can divide the spell range by 7,5 and you'll get the number of squares needed (just remember, any halves round down to the nearest whole).

So, a 30 ft. is 4 squares away from the origin square diagonally, and 6 squares away from origin square if not.

Technically, that's a variant rule (which, though more realistic, I think it's more trouble than it's worth)

[Arkhios]

Technically, that's a variant rule (which, though more realistic, I think it's more trouble than it's worth)

To be fair, I didn't say it was the default rule. I only said if you want to be a "stickler" (to the length of a square in feet, which is 5 ft x 5 ft).

[diplomancer]

To be fair, I didn't say it was the default rule. I only said if you want to be a "stickler" (to the length of a square in feet, which is 5 ft x 5 ft).

Fair enough, though in this context one might think you meant "being a stickler to the rules", not "being a stickler to real world geometry".

[Arkhios]

Fair enough, though in this context one might think you meant "being a stickler to the rules", not "being a stickler to real world geometry".

Then again, having grown to TTRPG with 3.5 and pathfinder 1e, diagonal square rule was the RAW and there was no other option, so I suppose it comes more naturally for me.

[Cheesegear]

Point of origin. Go 30 ft. (six squares) forwards.
Count the last row as final row, using the point as the centre.
Draw the triangle.
Colour in the boxes.

Spoiler

Show

However, you'll notice that that's stupid since it's entirely arguable that you miss the squares directly in front of you.

Skew the triangle to optimise area of effect.

Spoiler: 30-ft. Cone

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[IMG][/IMG]

Viola! It's still arguable that you miss the square directly in front of you. But as far as I'm concerned that's a discussion for your own table.
It's also very arguable that you lose the square on the top left, since technically that's 35 ft. away from the point of origin. But also the end is 30 ft. across? I allow it.

Xanathar's lets you add all squares in the triangle to save time and ease confusion.
I disagree.
Having a template saves time and eases confusion and you don't have to make Cones more powerful in the process.

[Martin Greywolf]

Found it, DMG 251:
Choose an intersection of squares or hexes as the point of origin of an area of effect, then follow its rules as normal. If an area of effect is circular and covers at least half a square, it affects that square.

I don't know if DMG uses the mathematical definition of intersecions, but if it does, then you can indeed put the origin of cone on the line between two squares, or anywhere on the border of the square you're currently in.

An intersection is a point, line, or curve common to two or more objects.

So, any line drawn on a battlemat is an intersection by mathematical definition, since it is a line shared by two neighbouring objects, or a point shared by two or more (4 on square grid, 3 on hex grids, also the lines are an infinite sets of points).

This interpretation also feels more 'right' to me, but that doesn't really mean much.

[sandmote]

Interesting. I hadn't realized Xan overrode the DMG rule from 1/2 covered to any part covered. Possibly because otherwise in your diagram you come up with 0 squares in the first row.

I mean, it only kind of overrides the DMG. As per your own quotation of the document, the DMG only comments on "If an area of effect is circular" and cones don't often have curves in their horizontal area, making their status on the subject debatable.

[diplomancer]

People sticking more strongly to the "N feet equals X squares" interpretation appear to be using the Token method.

Yeah, I was doing that; it's the method I like best, because it seems both simple and "fair", and you don't have the player trying to put the template at "just the right angle and position" to have the maximum squares possible in the AoE.