So, in Guildmasters's Guide to Ravnica the pyroconverger that uses a 10ft cone. How does that work in a grid? Should it have been 15ft? Especially in an angle it seems a bit odd...
I don't know anything about GGtR but there's nothing special to cones on a grid. If the cone touches a creature's space, they're in the area of effect, same as playing without a grid.
I've not looked it up, but I believe a 10' cone covers approximately 3 grid squares; one adjacent to the source, and then two behind the first one to form a vague triangle (you might be able to squeeze in another square or two by half covering them). A 15' cone similarly covers six squares in a row pattern 1 - 2 - 3. There are assorted ways to represent spell coverage on a grid involving rulers or templates or whatever (and I believe that a hex grid is much better for cones, spheres and cylinders, while being worse for cubes). If you are a player, ask your DM. If you are a DM, the only important thing is that the method(s) you choose are consistent, balanced and predictable, so that players know what they will get when they cast cone of cold, or when they get hit by a fireball.
The way the grid rules in the DMG work, it really doesn't matter much whether you're playing on a square grid, a hex grid, or no grid at all. If the cone touches someone's space, they're affected. There's no requirement to cover most of a square unless the area is circular. The only other adjustment the grid rules make is that if the point of origin for an area of effect is a point in space, it should be placed on a grid intersection.
A 10 foot cone should touch at least 4 squares, maybe 5 if you rotate it at certain angles.
Print it out, make a cardboard measuring tool and have every 5 foot square that is at least covered half way count as affected area. (That's how I handle it at my table; we use the 60° cone)
It all depends on whether you use a 45°, 60° or 90° cone, when taking a look at what it can reach.
There's only one kind of cone in 5e:
Cone
A cone extends in a direction you choose from its point of origin. A cone's width at a given point along its length is equal to that point's distance from the point of origin. A cone's area of effect specifies its maximum length.
A cone extends in a direction you choose from its point of origin. A cone's width at a given point along its length is equal to that point's distance from the point of origin. A cone's area of effect specifies its maximum length.
That's an angle of arctan(1/2) ≈ 53.13°
All of that may be true but none of it answers the question asked: how to do this in a grid system.
You need to start by deciding if/how you count partially covered squares. Pick an easy to follow rule and stick to it.
Start the cone at an intersection, not the center of a square. The cone goes out x ft, whatever the range is, in two directions that are 90 degrees apart from one another, starting from that intersection.
Basically, the cone is a 90 degree triangle on the grid, with the 2 sides extending out from the origin point by the length of the cone.
So pick your point of origin, and pick your orientation. Depending on orientation, some targets might be in squares that are partially covered by the triangle. Apply whatever rule you decided on in step one.
All of that may be true but none of it answers the question asked: how to do this in a grid system.
Uh, I answered that twice already. It's exactly the same as playing without a grid, except the cone's origin is placed on a grid intersection if it doesn't emanate from the caster (which is rare.) Whatever squares it touches get affected.
The cone certainly doesn't become a right triangle. Areas of effect don't change shape just because you're playing on a grid.
All of that may be true but none of it answers the question asked: how to do this in a grid system.
Uh, I answered that twice already. It's exactly the same as playing without a grid, except the cone's origin is placed on a grid intersection if it doesn't emanate from the caster (which is rare.) Whatever squares it touches get affected.
The cone certainly doesn't become a right triangle. Areas of effect don't change shape just because you're playing on a grid.
Right, but the question remains as to *how* you place the cone on the grid: do you get out some measuring tape and map it out? Do you get a set of 57 transparent plastic templates for each spell shape and size? Do you have the caster choose one target point then have the DM choose the affected squares, or let the caster choose all the affected squares and the DM only adjudicate if needed? Or do you agree on some exact grid layout shapes that will represent spell areas? That question is not actually answered in the books, and is clearly complex enough that Xanathars has had to go into it in some significant detail. The final advice from us, though, is that you pick whichever of these methods you want (for speed, convenience, fun) and that it will be fine as long it applies consistently in all cases.
Personally, I use grid layout shapes and I play on hexes so a cone is a very easy shape: 1 hex, row of 2, 3, 4. A square grid makes much more of a mess of a cone using that same method.
Just lay the cone out, if it touches a grid then that area is hit. The grid represents a creature's area of control and so if that creatures has an area of control then they are hit by something that enters any part of that area. A cone moves into 1/4 or 1/2 a grid? It hits
If you want to use a 10' cone on a square grid and its on a face edge, then its first square and square behind it in the second row, with one extra square on the left or right of that one. If its out of the corner then it ends up looking like an L, (which is weird I know) or a V either way if your using a grid map a 10' cone could only hit 3 people maximum. Do bear in mind that this is a hold over from previous editions and assumes everyone is spreading out enough to avoid being unimpaired by proximity from another combatant (no squeezing penalty) and it might even be 'impossible' to remain in anothers space at the end of your turn with current rules unless riding, 'climbing' or a special ability like an oozes 'squeezing.' Whether or not you use any of this is up to the DM.
I.C. I would point out that if your going as far as reducing diagonal movement on every second diagonal by doubling distance travelled then cones should also fall along the same guidelines. At the very least only something over 50% covered should be affected by a cone - the models may be stationary but the creatures they represents wont swarm all the shiny AOE lights for fun.
So, in Guildmasters's Guide to Ravnica the pyroconverger that uses a 10ft cone. How does that work in a grid? Should it have been 15ft? Especially in an angle it seems a bit odd...
Subclass: Dwarven Defender - Dragonborn Paragon
Feats: Artificer Apprentice
Monsters: Sheep - Spellbreaker Warforged Titan
Magic Items: Whipier - Ring of Secret Storage - Collar of the Guardian
Monster template: Skeletal Creature
I don't know anything about GGtR but there's nothing special to cones on a grid. If the cone touches a creature's space, they're in the area of effect, same as playing without a grid.
The Forum Infestation (TM)
I've not looked it up, but I believe a 10' cone covers approximately 3 grid squares; one adjacent to the source, and then two behind the first one to form a vague triangle (you might be able to squeeze in another square or two by half covering them). A 15' cone similarly covers six squares in a row pattern 1 - 2 - 3. There are assorted ways to represent spell coverage on a grid involving rulers or templates or whatever (and I believe that a hex grid is much better for cones, spheres and cylinders, while being worse for cubes). If you are a player, ask your DM. If you are a DM, the only important thing is that the method(s) you choose are consistent, balanced and predictable, so that players know what they will get when they cast cone of cold, or when they get hit by a fireball.
The way the grid rules in the DMG work, it really doesn't matter much whether you're playing on a square grid, a hex grid, or no grid at all. If the cone touches someone's space, they're affected. There's no requirement to cover most of a square unless the area is circular. The only other adjustment the grid rules make is that if the point of origin for an area of effect is a point in space, it should be placed on a grid intersection.
A 10 foot cone should touch at least 4 squares, maybe 5 if you rotate it at certain angles.
The Forum Infestation (TM)
It all depends on whether you use a 45°, 60° or 90° cone, when taking a look at what it can reach.
https://www.dmsguild.com/images/8957/195778.jpg (free template, so I will link it here)
Print it out, make a cardboard measuring tool and have every 5 foot square that is at least covered half way count as affected area. (That's how I handle it at my table; we use the 60° cone)
There's only one kind of cone in 5e:
That's an angle of arctan(1/2) ≈ 53.13°
The Forum Infestation (TM)
There's only
All of that may be true but none of it answers the question asked: how to do this in a grid system.
You need to start by deciding if/how you count partially covered squares. Pick an easy to follow rule and stick to it.
Start the cone at an intersection, not the center of a square. The cone goes out x ft, whatever the range is, in two directions that are 90 degrees apart from one another, starting from that intersection.
Basically, the cone is a 90 degree triangle on the grid, with the 2 sides extending out from the origin point by the length of the cone.
So pick your point of origin, and pick your orientation. Depending on orientation, some targets might be in squares that are partially covered by the triangle. Apply whatever rule you decided on in step one.
Uh, I answered that twice already. It's exactly the same as playing without a grid, except the cone's origin is placed on a grid intersection if it doesn't emanate from the caster (which is rare.) Whatever squares it touches get affected.
The cone certainly doesn't become a right triangle. Areas of effect don't change shape just because you're playing on a grid.
The Forum Infestation (TM)
Right, but the question remains as to *how* you place the cone on the grid: do you get out some measuring tape and map it out? Do you get a set of 57 transparent plastic templates for each spell shape and size? Do you have the caster choose one target point then have the DM choose the affected squares, or let the caster choose all the affected squares and the DM only adjudicate if needed? Or do you agree on some exact grid layout shapes that will represent spell areas? That question is not actually answered in the books, and is clearly complex enough that Xanathars has had to go into it in some significant detail. The final advice from us, though, is that you pick whichever of these methods you want (for speed, convenience, fun) and that it will be fine as long it applies consistently in all cases.
Personally, I use grid layout shapes and I play on hexes so a cone is a very easy shape: 1 hex, row of 2, 3, 4. A square grid makes much more of a mess of a cone using that same method.
Just lay the cone out, if it touches a grid then that area is hit. The grid represents a creature's area of control and so if that creatures has an area of control then they are hit by something that enters any part of that area. A cone moves into 1/4 or 1/2 a grid? It hits
If you want to use a 10' cone on a square grid and its on a face edge, then its first square and square behind it in the second row, with one extra square on the left or right of that one. If its out of the corner then it ends up looking like an L, (which is weird I know) or a V either way if your using a grid map a 10' cone could only hit 3 people maximum. Do bear in mind that this is a hold over from previous editions and assumes everyone is spreading out enough to avoid being unimpaired by proximity from another combatant (no squeezing penalty) and it might even be 'impossible' to remain in anothers space at the end of your turn with current rules unless riding, 'climbing' or a special ability like an oozes 'squeezing.' Whether or not you use any of this is up to the DM.
I.C. I would point out that if your going as far as reducing diagonal movement on every second diagonal by doubling distance travelled then cones should also fall along the same guidelines. At the very least only something over 50% covered should be affected by a cone - the models may be stationary but the creatures they represents wont swarm all the shiny AOE lights for fun.
It's 2*arctan(1/2) ≈ 53.13°, but yeah :-)
≈ 25.56° to either side.