Clarification for Area of Effect Templates

Question

I have seen a lot of AOE templates out there. There seems to be a lot of interpretations.

I have seen some that equate 20' squares and 20' radius circle. However, 20' squares are 4x4 squares on a 1sq=5ft map, and 20' radius circles are closer to 8x8 squares. I've seen the squares given bigger areas to make them equal and circle made into diameters, therefore smaller, to make them equal. Both are wrong, but circles do seem over powered, comparatively.

Also, there are "grid circle" templates out there, but they place the point of origin on a cross in between 4 squares. Wouldn't a centerpoint of a single square be the point of origin on an AOE that originates from the "self"?

I've seen cones that are equilateral triangles with all sides equal to the given distance of the cone (meaning they have 3 60deg angles) starting at the midpoint or corners of the square the PC is on. I've also seen them start at the midpoint or corner of the PC's square but with a 45deg angle and 2 67.5deg angles in 2 variations (the line in the middle being the distance given or the two protruding sides of the triangle being the distance given). You can also have the distance given as the center of an isoceles and at that edge the center of a perpendicular line, also the distance given. Can you start on any point of the creature's square(s)? Another version looks as though a protractor has been used with the given distance, giving the far third of the triangle a curve. Not to mention the "grid cone" which can only be used in 4 directions (not 8) given the cone necessitates a single square at the beginning.

Only lines seem to have a clearly designated template, but even they get wonky when you add the direction of attack can mean they aren't placed directly in line with the battle map grid (attacking enemies at an angle) and therefore how much of an enemy's square does the template need to cover to be considered a hit? Completely? Mostly? Over 50%? 25%? Touching at all?

I want to have clear and consistent rulings for these topics at my table to help foster fair play. Any insight?

Answer 1

There are multiple different rules to choose from

The reason that you see so many contradictory takes is because the 5e rules provide a number of different ways to resolve areas of effect.

The rules

1. Narrative combat. If you use narrative combat, there is not even a floor plan to apply templates to. Instead, under Adjudicating Areas of Effect on p. 249, the DMG gives you a formula on how to calculate the number of affected targets. "This approach aims at simplicity instead of spatial precision. If you prefer more tactical nuance, consider using miniatures.". Narrative combat is actually the default, playing a grid is a "variant" rule (p. 192 PHB).

2. Just miniatures, No grid. The intro (p. 6 PHB) states you can use miniature figures "to represent each creature involved in a scene to help the players keep track of where everyone is.", but does not mandate a grid. That is, while a grid of 5-foot squares and minis is the most commonly used setup, you also can play without grid. In such cases, the templates can exactly fit the area descriptions in the spellcasting rules, with whatever scale for your minis you use. Partially being in the area of effect is being in the area of effect, so any amount of overlap by the template over a figure will mean the creature is affected.

3. 5-foot square or hex grid, core rules. The core rules (DMG, p. 251) tell you to use an exact template of the shape given in the spellcasting section as your template, and then determine which squares are affected as follows¹: 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.

4. The template method, an optional rule from Xanathar's Guide to Everything (XGE), p. 86, again uses templates in the exact shape from the spellcasting rules, but now any square that is overlapped by the template is affected. "If any part of as quare is under the template, that square is included in the area of effect. If a creature's miniature is in an affected square, that creature is in the area.", which makes it easier to decide if a square is affected or not, and increases the number of affected squares. It also recommends to use this method without a grid, and states "If you do so, a creature is included in an area of effect if any part of the miniature's base is overlapped by the template", the same as answer 2, with the slight difference that the base of the miniature is used, not the miniature.

5. The token method from XGE, p. 87, instructs you to "make areas of effect tactile and fun", by putting a 6-sided die or other token in each affected square of a square grid. I have never seen anyone actually use it, but for the layout of these dice, predefined patterns are provided. Cones now only work at orthogonally or diagonally, lines too, and circles of a given diameter here are depicted as squares as long on each side. This may explain why some of the templates you have seen depict cicular areas as squares (unless they are from 4e D&D, which also did that).

Readymade templates for 5-foot squares

Exact templates can be oriented at any angle, not just orthogonally or diagonally to a grid that you play on. However, if you use method number 3, it can save you a lot of time for circular areas of a given size (cylinder or sphere, where rotation angle orthogonally to the ground does not matter), or for squares and cones of a given size that are used orthogonally or diagonally to the grid, and for lines at some additional angles, to already prepare templates that show the affected squares, like here for Pathfinder. When you use these templates at these angles, you can directly see which square is affected. For example, here are the templates for affected squares on the ground for fireball in 5e, cast at various heights over ground. Note that because the rules differ between 5e and earlier editions, sometimes you run into templates online that show areas that would be incorrect under 5e rules, like the ones for a 20-foot circle from Pathfinder.

Spell areas of effect

These are all listed on p. 201, PHB, and any exact template that is correct would need to match them (and affected-square templates would need to match them after translating to squares following the rules). For example

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 means at a distance of 20 feet, a cone would be 20 feet wide. This is not going to create a triangle with equal angles and sides if seen from above as a template, it is going to be more narrow.

The depiction of the areas shows that the end of the cone would be a flat circular cross-section. For Cones, Cubes and Lines, the caster can decide if the point of origin is included in the area, for cylinders and spheres it always is.

Placing the point of origin

The rules (PHB, p. 201) say:

Every area of effect has a point of origin, a location from which the spell’s energy erupts. The rules for each shape specify how you position its point of origin. Typically, a point of origin is a point in space, but some spells have an area whose origin is a creature or an object

When playing on a grid, for spells that have a normal point of origin, the core rules in 5e are clear

Choose an intersection of squares or hexes as the point of origin of an area of effect

However, there are spells that emanate from a creature, and in this situation the core rules are ambiguous. You could either pick a corner of the creatures grid cell, or the center of the grid cell. So to your question:

there are "grid circle" templates out there, but they place the point of origin on a cross in between 4 squares. Wouldn't a centerpoint of a single square be the point of origin on an AOE that originates from the "self"?

the answer is: both are valid ways to do it.

It also is interesting that the PHB rules (p. 201) say "The rules for each shape specify how you position its point of origin., but these rules only explain where to put the point of origin in the area of effect, not where it will be on the map. Spells like burning hands, cone of cold, and color spray instead explicitly tell us that the cone emanates from the casters hands, so that is where the point of origin must be.

So, to summarize, the reason that this is all confusing and you see a lot of variety is that the writers of 5e tried to be many things to many people, and did not stick to one way how to do this. Plus, there are wrong depictions and templates out there. You need to pick one way you will use, and consistently use that if you look to be clear and consistent.

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¹ This rule is incomplete, as it does not explain how to deal with other shapes that do not fully cover a square (or hex, for that matter). Most people assume they should use the same rule as for circular areas, and count squares that are overlapped more than half.

Answer 2

The DMG (p.251) deals with it simply and concisely

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.

So, the point of origin is always a corner of a square. There’s no room for ambiguity here.

While it does say “circular”, it’s probably best to interpret the last sentence as applicable to all areas of effect. If you do that, there’s no ambiguity here either - if it covers at least half the square, that square is affected.

Where there is room for ambiguity is in the piss-poor definitions of the areas of effect. The various areas of effect are detailed here.

• A cone is 53.14 degrees at the origin and can go in any direction. This one works, but if taken literally, it can be oriented in such a way that it doesn’t affect either of the two adjacent squares, for example, if you orient it to a line, which just seems silly.
• A cube’s point of origin is anywhere on a face. It doesn’t say this can be oriented as the caster likes, but it also doesn’t give a default orientation. So, it probably can be oriented as you like.
• A cylinder’s point of origin is the centre of the top or bottom and they always go straight down or up respectively from there and the bottom must be on the ground.
• A line “extends from its point of origin in a straight path up to its length and covers an area defined by its width.” Which doesn't actually tell you in which direction the “width” goes - is it the centre? One side? Anywhere you like? Probably best if you go with one side, as using the centre and firing it along a grid line will allow you to hit twice as many squares as any other orientation.
• A sphere comes from the centre. This works.

So, we can take away from this that the authors of the Player’s Handbook should not be trusted with writing rules for anything important, like legislation or instruction manuals for aircraft, because their grasp of clear and accurate English is just too low.

Alternative Rules

Xanathar's Guide to Everything (pp.86-90) contains two alternative methods for determining areas of effect on a grid that is inconsistent with the rules in the core rulebooks and each other.

The Template Method requires cutting shapes from paper or card stock (clear plastic is even better because it's transparent) and placing them on the grid "follow[ing] all the rules in the Players Handbook". The difference between this method and the DMG is that if any part of the template covers a square, that square is included. So, for example, a Fireball covers 44 squares under the original method but 52 under this one.

The Token Method "is meant to make areas of effect tactile and fun ... [r]ather than faithfully representing the shapes". It's even less accurate, depicting circles as squares, broadening out cones, and limiting lines to orthogonal and diagonals.

These methods both work on their own terms and are less ambiguous than the core rules.

Your table, your rules

As the DM, you need to decide what happens at the table. Just be consistent; you can’t be wrong.

Answer 3

Note regarding AoE lines (like Lightning Bolt)

Depending on the rule set you choose (which are perfectly explained in the answers already) the exact amount of effected 5-ft. tiles slightly differs only. In most cases, that is, because there is an exception:

Spells like Lightning Bolt

A stroke of lightning forming a line 100 ft long and 5 feet wide (...)

can effect 20x1 tiles or 20x2 tiles, which plainly doubles the effected space:

Casting this spell from a corner of the spell caster's tile, parallel along the grid, i.e. the center of the bolt runs always between two adjacent tiles. So both lines of tiles adjacent to the bolt center line are subject to 50 % of the spell. If the chosen rule says that such tiles are inside of the effect than a total of 40 tiles is in the Area of Effect.

This example shows how important it is to have agreed on a rule set beforehand.

Note: This example is valid also if the orgin of the spell is the spellcaster (the center of the spell) itself and the spell is cast in an angle (i.e. not parallel) to the grid. The difference of effected tiles is smaller, that's all.