I've been wanting to make up some templates for AOE spells and I was looking at some that other people have done but they seem to all place the point of origin on an intersecting line segment (which would give you more coverage).
Directly from the basic rules; A sphere's point of origin is included in the sphere's area of effect.
To me that seems that you have to use a center of a square as the point of origin.
I guess what I'm wondering is, should the point of origin be the center of a square, or the intersection of four squares. In our games at home we've been using the center of a square as the point of origin (which I believe is RAI), but I'd hate to make up a bunch of templates and have them be wrong.
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"In the beginning the universe was created.
This has made a lot of people very angry and been widely regarded as a bad move."
As far as the Area of Effect is concerned, cubes and squares behave alike. So the point of origin is not included in the cube/square's area of effect, unless you decide otherwise. It can be the intersection, but the important thing is that the point if on a face/side of the cube/square.
The lines on the map are an abstraction anyhow, are there grids on the street the moment a fight breaks out?
Whether you place the template on the line or in the square doesn't matter, it's simply a tactical advantage to see the grid there. In the theater of the mind that would translate to "I cast fireball so that I'll be able to hit the 3 creatures furthest away, but just a bit to the left so I can tag the boss too."
I've been wanting to make up some templates for AOE spells and I was looking at some that other people have done but they seem to all place the point of origin on an intersecting line segment (which would give you more coverage).
When creating an area of effect whose point of origin is a point in space, the Dungeon Master's Guide's rules for playing on a grid require placing the point of origin on a grid intersection.
Note that the rules of the game don't assume you're playing on a grid.
Directly from the basic rules; A sphere's point of origin is included in the sphere's area of effect.
This bit of text in the rules for each area of effect is only relevant for cases where the point of origin is a creature or object. When it's a point in space, the volume excluded would effectively be 0.
In practical terms what that means is that when you cast Lightning Bolt or Thunderwave, you're not included in the area unless you want to be for some weird reason, since the rules for lines and cubes and cones exclude the point of origin by default.
To me that seems that you have to use a center of a square as the point of origin.
Only if the point of origin for the spell is a creature (e.g. Antimagic Field), in which case it emanates from the creature's space
I guess what I'm wondering is, should the point of origin be the center of a square, or the intersection of four squares. In our games at home we've been using the center of a square as the point of origin (which I believe is RAI), but I'd hate to make up a bunch of templates and have them be wrong.
If you're using the grid rules in the DMG and the area of effect targets a point in space, it should be placed on a grid intersection. If you're not using a grid or don't care about the DMG's grid rules, you can place the point of origin anywhere you like; if a creature's space overlaps the spell's area, they're affected.
The lines on the map are an abstraction anyhow, are there grids on the street the moment a fight breaks out?
Whether you place the template on the line or in the square doesn't matter, it's simply a tactical advantage to see the grid there. In the theater of the mind that would translate to "I cast fireball so that I'll be able to hit the 3 creatures furthest away, but just a bit to the left so I can tag the boss too."
I believe it actually does matter. If the area in question is a sphere with radius 5', and you center in in a square, are creatures in the squares adjacent to it affected? Their squares are only half covered by the area. If you rule "a square that is half covered is not affected", then the area is effectively only 2.5' in radius. If you rule "a square that is half covered is affected", then the area is effectively 7.5' in radius. That is a significant difference. If creatures could occupy "parts of squares", or could "squish" into a side of a square, then it might work: creatures are affected by an area that covers half the square they are in if they are in that part of the square. But that's not how the game works; creatures are either in the square, or they're not. So, since areas are given in multiples of 5', centering them on a point (intersection of lines) solves the problem neatly. Areas that are centered on objects or creatures are usually expressed differently ("affects the creature and any creatures within 10' of it"), to also sidestep the "half square" problem. This means, though, that a spell that affects "a 5' radius sphere" has a smaller area of effect than one that affects "a creature and all creatures within 5' of it". The former is a sphere with radius 5', the latter a sphere with radius 7.5'.
You are correct, your interpretation of the grid mechanics and geometry make perfect sense.
What I was getting at is how do you manipulate those numbers without a grid, without squares, and without any miniatures? If I describe a room that is 85ft long by 25ft wide, it has a 12ft ceiling and there's a concave pit in the floor that descends about 18 inches. I then explain that in this room there are 9 goblins spread out ready to attack, and a roper on the ceiling. As you are right now, with no battle mat, no grid, no stencil, those numbers don't mean too very much when it comes to placing the spell to affect the "square" that the goblin is in.
I know it deviates from the OP's question but it was something I felt was worth mentioning.
So, since areas are given in multiples of 5', centering them on a point (intersection of lines) solves the problem neatly.
Not really. Spheres, cylinders and cones will always leave some squares partially covered and the rules for grids don't force you to align a cube or line with the grid. You can rotate a cube spell so it's standing on one of its corners or edges, and you can shoot a line spell at an 80 degree angle.
You're going to run into situations where spells only partially overlap a creature's space with or without a grid. Placing the point of origin in a grid intersection mainly makes it easier to use the grid as a ruler.
Lightning Bolt doesn't care if it covers your whole space or only clips it; if it overlaps your space in any way, you're targeted.
So, since areas are given in multiples of 5', centering them on a point (intersection of lines) solves the problem neatly.
Not really. Spheres, cylinders and cones will always leave some squares partially covered and the rules for grids don't force you to align a cube or line with the grid. You can rotate a cube spell so it's standing on one of its corners or edges, and you can shoot a line spell at an 80 degree angle.
You're going to run into situations where spells only partially overlap a creature's space with or without a grid. Placing the point of origin in a grid intersection mainly makes it easier to use the grid as a ruler.
Lightning Bolt doesn't care if it covers your whole space or only clips it; if it overlaps your space in any way, you're targeted.
Certainly true. I meant it solves the problem of ALL areas having partially filled squares, which stems from areas being given in multiples of 5'.
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I've been wanting to make up some templates for AOE spells and I was looking at some that other people have done but they seem to all place the point of origin on an intersecting line segment (which would give you more coverage).
Directly from the basic rules; A sphere's point of origin is included in the sphere's area of effect.
To me that seems that you have to use a center of a square as the point of origin.
I guess what I'm wondering is, should the point of origin be the center of a square, or the intersection of four squares. In our games at home we've been using the center of a square as the point of origin (which I believe is RAI), but I'd hate to make up a bunch of templates and have them be wrong.
"In the beginning the universe was created.
This has made a lot of people very angry and been widely regarded as a bad move."
As far as the Area of Effect is concerned, cubes and squares behave alike. So the point of origin is not included in the cube/square's area of effect, unless you decide otherwise. It can be the intersection, but the important thing is that the point if on a face/side of the cube/square.
The lines on the map are an abstraction anyhow, are there grids on the street the moment a fight breaks out?
Whether you place the template on the line or in the square doesn't matter, it's simply a tactical advantage to see the grid there. In the theater of the mind that would translate to "I cast fireball so that I'll be able to hit the 3 creatures furthest away, but just a bit to the left so I can tag the boss too."
When creating an area of effect whose point of origin is a point in space, the Dungeon Master's Guide's rules for playing on a grid require placing the point of origin on a grid intersection.
Note that the rules of the game don't assume you're playing on a grid.
This bit of text in the rules for each area of effect is only relevant for cases where the point of origin is a creature or object. When it's a point in space, the volume excluded would effectively be 0.
In practical terms what that means is that when you cast Lightning Bolt or Thunderwave, you're not included in the area unless you want to be for some weird reason, since the rules for lines and cubes and cones exclude the point of origin by default.
Only if the point of origin for the spell is a creature (e.g. Antimagic Field), in which case it emanates from the creature's space
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You are correct, your interpretation of the grid mechanics and geometry make perfect sense.
What I was getting at is how do you manipulate those numbers without a grid, without squares, and without any miniatures? If I describe a room that is 85ft long by 25ft wide, it has a 12ft ceiling and there's a concave pit in the floor that descends about 18 inches. I then explain that in this room there are 9 goblins spread out ready to attack, and a roper on the ceiling. As you are right now, with no battle mat, no grid, no stencil, those numbers don't mean too very much when it comes to placing the spell to affect the "square" that the goblin is in.
I know it deviates from the OP's question but it was something I felt was worth mentioning.
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