Monstrous Compendium Vol. 1: Spelljammer Creatures
Frozen Sick
D&D Beyond Basic Rules
Basic Rules (2014)
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Monstrous Compendium Vol. 1: Spelljammer CreaturesFrozen SickD&D Beyond Basic RulesBasic Rules (2014)Sign in to view your library & saved favorites.
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Okay, so I'm a bit confused by this and am hoping someone could help me out. The new rules for Area of effect are as follows:
"A Sphere is an area of effect that extends in straight lines from a point of origin outward in all directions. The effect that creates a Sphere specifies the distance it extends as the radius of the Sphere. A Sphere’s point of origin is included in the Sphere’s area of effect.
A Cube is an area of effect that extends in straight lines from a point of origin located anywhere on a face of the Cube. The effect that creates a Cube specifies its size, which is the length of each side. A Cube’s point of origin isn’t included in the area of effect unless its creator decides otherwise."
If we are playing on a grid, I am gathering that a sphere is actually a cube, but the point of origin must be the center of the cube,
whereas a cube area of effect only differs from a sphere by its point of origin being the caster's choice? Is this right?
I just don't fully understand what the ramifications, or difference in this is, and why Fairie fire is a cube, whereas fireball is a sphere?
Fireball has "ball" in the name and a ball is a sphere. Faerie Fire is just targeting a cube area and it being a sphere would be needlessly irrelevant.
But if you drew out the "sphere" area of effect on a grid, it would be a square/cube, not circle/sphere based on the rules above.
I'm confused about your confusion. Both are the same, it's mostly just a pedantic visual qualifier so that you don't have people arguing the other way about how round spells shouldn't mechanically be cubes. Game-wise, it doesn't matter since a 15ft cube and a 15ft sphere effect the same stuff.
Based on the definitions presented, a 15ft sphere would be nearly 4x the size of a 15ft cube (radius vs. side length). Besides that, on a grid (assuming actual values that produce similarly sized shaped), there won't be much of a difference. However, if your maps add any verticality to them, then the differences can start to get pretty apparent. Then there are the people who don't play on a grid and the differences there will matter.
Ok, I am looking further into this myself and came across your post and I've figured out enough to be able to help you, at least.
So to understand the difference we first have to establish understanding of a few components of an Effect that has an Area of Effect, which are the Shape and the Point of Origin.
The Shape determines the Targets of the Effect. For instance, if the Shape is a Sphere, then everything that is within the Sphere are possible Targets. Whether Spheres are Cubes is left as an exercise for the reader.
So, why are the Targets only possible Targets so far?
Because there is a second step to resolving what is actually Targeted by the Effect, which is resolving if the Target is actually affected by the Effect. There a multiple things that can remove a possible Target from the Effect.
The first consideration is whether the Effect can Target only Creatures, only Objects, or both. If it can't Target Objects, then an Object is not a Target even though it is in the Area of Effect and so is not affected by the Effect.
The next helps to understand what the Point of Origin is, and that is determining a clear path to the Target. If a Target of the Effect is behind Total Cover from the Effect, then the Effect does not have a clear path to the Target and it cannot be affected by the Effect. (Note: Specific beats general, so if the Effect can ignore Total Cover, it will say so.)
The easiest reference to use for this rule is in the section on Casting a Spell of the PHB -
"A Clear Path to the Target. To target something with a spell, a caster must have a clear path to it, so it can’t be behind Total Cover."
So how does one determine a clear path to the Target for an Area of Effect. The Shape will specify this in its definition. For a Sphere, it says -
"...is an area of effect that extends in straight lines from a point of origin outward in all directions. ..."
So to resolve a clear path to a Target, we start from the Point of Origin and use the rules for determing a clear path from the rules for Cover. When not playing on a grid, the Cover is entirely decided by the DM or House Rules in effect. When playing on a grid, the DMG suggests the following -
"To determine whether a target has cover against an attack or other effect, choose a corner of the attacker’s space or the point of origin of an area of effect. Then trace imaginary lines from that corner to every corner of any one square the target occupies. If one or two of those lines are blocked by an obstacle (including a creature), the target has Half Cover. If three or four of those lines are blocked but the attack or effect can still reach the target (such as when the target is behind an arrow slit), the target has Three-Quarters Cover."
In this case the Point of Origin of the Sphere Area of Effect would be at the center of the Sphere's Shape and that would be used to determine all valid Targets of the Effect.
Finally, to compare that to a Cube, the rule is different for a Cube Area of Effect -
"... is an area of effect that extends in straight lines from a point of origin located anywhere on a face of the Cube. ..."
Here you are given more choice than the Sphere, because the Sphere must use its center as the Point of Origin, but the Cube can use any location on a face of the Cube to make these same checks. This means that you may be able to affect a Target with a Cube, along with other Targets, in the same Area of Effect, but the Sphere may force a choice, because its Point of Origin is resolved differently.
I hope that, after waiting two years, this answer finds you well. I also hope this revives some visibility for others that may be curious.
The thing that I am still trying to track down is more insight into resolving placement of the Shape of an Area of Effect based on specific Ranges of Effects. I.e. Thunderwave is a Cube with a Range of Self, but Faerie Fire is a Cube with a Range of 60', so when I place each Effect, where do I place the Shape in relation to the Range? The Thunderwave could be adjacent to me, meaning it can affect Creatures and Objects outside of the initial range, but does that mean the Faerie Fire can start 60' away and its Cube can be adjacent to that location within Range, thus affecting Creatures more than 60' away in that case?
The Sphere describes where the Shape is in relation to the Point of Origin, so the location, Shape, and Point of Origin can all safely be assumed to be the same. That's not true for Cubes, and the rules do not clarify this.
Further, since the Cube can use a Point of Origin on any face of the Cube, this can include the top face. In this way, a clear path to the Target can be resolved to a Target I don't have line of sight to. This means I can affect a Creature I cannot see! So, is it assumed, unless the spell also says Target(s) I can see, that Target is affected even though I cannot see it? I can see many DMs not feeling comfortable ruling it that way, in which case why write the Rules this way?
I hope that in 6th Edition they work to make these rules very clear to DMs and Players! I know that the rules are there to facilitate the fun, but how fun can it be when the Players and the DM think they're playing two different games and constantly surprise each other with how the world works! Part of "facilitating the fun" means a baseline agreement that generally works so that the game can happen! When I sit down and play with two groups the fewer times I'm asking "so how do you run XYZ?" the more time I'm spending immersed in a story with fellow humans!
So yes, the rules do matter and no it can't just always be "whatever the DM says" because, even when that is the case, that's not D&D, that very quickly becomes "Mother May I?"! And unless you're an incorrigible little British orphan, you're probably not interested in playing that, you want to play D&D!