Fireball Through A Distant Arrow Slit

[JNAProductions]

So, this came up in another thread.

A Wizard is standing somewhere, and wants to fire a Fireball through an arrow slit, about 60' away. He aims to have it explode on the other side of the arrow slit.

What would you, as a DM, do in this situation?

Me personally, I would rule that he'd need to make a spell attack roll (so, Int mod+Proficiency mod) versus AC 15 to "hit" the arrow slit and have it pass through, otherwise it would impact against the wall and go boom on the wrong side.

What would the rest of the forum do?

[SkylarkR6]

Hmmm fireball is cast to a chosen point in range. I'd say it would come down to "Can the wizard see a chosen point on the other wide of the arrow slit?" If no due to darkness, bad angle or what have you, he can't. If it's well lit on the other side and archers be shooting out of it visibly? Hell yeah toast em. It's a cool visual and will make the wizard feel badass

[Contrast]

Depending on the nature of the obstacle - if it provides total cover, they can't do it. If they can see through but it doesn't provide total cover but there's a question as to if they can see through I'd probably make some sort of perception check to see if they can perceive what they're trying to focus the magic on.

I'd never make someone roll to hit with a fireball spell. That's not how the spell works.

[Unoriginal]

As long as they can see through the slit from where they stand, they should be able to without problem.

Of course, the question is what they can see through a narrow hole at such a distance.


Also, since a Fireball's explosion isn't blocked by angles, it's logical to assume that the explosion goes through holes if they are in its radius. So even if the Fireball exploded in the slit/on the wrong side, the explosion would still go through.

[LeonBH]

I'd be irritated that my DM made me roll a spell attack for a spell that doesn't require such a roll, because even if I hit, the affected targets will probably still make Dex saves. So the chances are tilted on the side of the enemies.

As long as the caster can see through the slit, and there is no total cover or anything blocking line of sight, they should be able to cast Fireball through it.

[Malifice]

So, this came up in another thread.

A Wizard is standing somewhere, and wants to fire a Fireball through an arrow slit, about 60' away. He aims to have it explode on the other side of the arrow slit.

What would you, as a DM, do in this situation?

Me personally, I would rule that he'd need to make a spell attack roll (so, Int mod+Proficiency mod) versus AC 15 to "hit" the arrow slit and have it pass through, otherwise it would impact against the wall and go boom on the wrong side.

What would the rest of the forum do?

Spell attack roll vs AC 15.

Same as you.

[E’Tallitnics]

The spell doesn’t even require that the caster be able to see the end point. It merely has to be within range and the “bright spark” simply goes there.

You would account for cover as usual, but only after detonation.

The only consideration is if the caster has, “A Clear Path to the Target” (PH, p.204).

[Laserlight]

No attack roll required. If you can see it, you can hit it.

[pdegan2814]

The spell says "a bright streak flashes from your pointing finger to a point you choose within range", so I would argue that a solid wall would block it, but as long as the point can be reached via a straight line from the caster, then it would work. You could argue that the caster might have to say something like "50 feet beyond the arrow slit in that direction" rather than "in between those two orcs", as the distance between the caster and the arrow slit would affect what he could see on the other side.

[Ganymede]

I think "roll to hit" is a decent way to determine if the PC can actually see past the arrow slit with enough acuity. It probably wouldn't matter a whole much as the fire spreads around corners and would presumably spread into the area past the arrow slit.

Back in the day, an arrow slit was an example of the type of cover that could potentially cause a fireball to detonate prematurely.

[Cybren]

The spell doesn’t even require that the caster be able to see the end point. It merely has to be within range and the “bright spark” simply goes there.

You would account for cover as usual, but only after detonation.

The only consideration is if the caster has, “A Clear Path to the Target” (PH, p.204).

Clear path to the target requires that the caster has the clear path. If they can't see the end point they don't have a clear path. (not that you literally need to be able to see it. you can cast a fireball into darkness, but it's absurd to say that the end point could bend around corners or through obstacles directly obstructing the path)

[kitanas]

Clear path to the target requires that the caster has the clear path. If they can't see the end point they don't have a clear path. (not that you literally need to be able to see it. you can cast a fireball into darkness, but it's absurd to say that the end point could bend around corners or through obstacles directly obstructing the path)

The actual tex for that is "if you place an area of effect at a point you can't see and an obstruction, such as a wall, is between you ant that point. the point of origin comes into being on the near side of that obstruction." So by RAW, if he is within range, he can totally place it there, because fireball lacks the text "place you can see". if an arrow can fire out of it, a fireball can fire into it.

[Cybren]

The actual tex for that is "if you place an area of effect at a point you can't see and an obstruction, such as a wall, is between you ant that point. the point of origin comes into being on the near side of that obstruction." So by RAW, if he is within range, he can totally place it there, because fireball lacks the text "place you can see". if an arrow can fire out of it, a fireball can fire into it.

i don't know what you're trying to say here. Are you saying that you could target the fireball on a space that isn't visible through the slit? If so, that's nonsensical. Are you trying to say you can target the fireball through the space visible through the slit? That's the entire question of the thread.

[Tanarii]

The point is the PC needs an unobstructed line. They don't need to be able to see the other side. It's entirely possible that they wouldn't be able to clearly see through an arrow slit, given the way they are designed, at some significant range but still with the FB spells range, but have an unobstructed line to the other side.

Being able to precisely place spells like fireball with pinpoint precision is an artifact of the simplicity of the system.

I certainly wouldn't object if a DM asked for some kind of check to pull it off, be it through a narrow opening, or targeting it so it affected an enemy adjacent to and engaged with an ally in melee. Dex check vs a fixed DC or spell casting mod attack roll vs an AC would both be fine with me.

As a DM I've never bothered, but probably a Dex or Int check would be the first thing I'd be inclined to go with. Mostly because I'm a fan of using attribute checks for anything where there's a question of resolution, unless a specific check is already called for.

[Kane0]

Sure why not, if the caster has line of sight.

[kitanas]

i don't know what you're trying to say here. Are you saying that you could target the fireball on a space that isn't visible through the slit? If so, that's nonsensical.

Regardless of of sencial or not you think it is, that is how it works by RAW. the general rule is that spells do not need line of sight. most spells, and especially most combat spells, have specific text overriding this, but fireball is an exception. TO give another example of this principal in action, scrying, sending, and sending all lack text that you need to see the the target, as well as text specifying that you do not need to see the target.

If you can site me rules text proving me wrong go ahead, or state that you are running it differently, which is fine. I am just trying to state what RAW is.

[Cybren]

You literally quoted the text that says what happens when you target an area of effect past an obstruction

[kitanas]

You literally quoted the text that says what happens when you target an area of effect past an obstruction

Are you arguing that a wall with enough of a hole to let an arrow out doesn't have a big enough hole to let the fireball in? If it was solid, I would agree that you can't send a fireball past it, but it has that arrow slit.

[Cybren]

Are you arguing that a wall with enough of a hole to let an arrow out doesn't have a big enough hole to let the fireball in? If it was solid, I would agree that you can't send a fireball past it, but it has that arrow slit.

I'm arguing that the fireball goes in a straight line from the caster to the intended effect, not a weird zig-zaggy mess.

[kitanas]

I'm arguing that the fireball goes in a straight line from the caster to the intended effect, not a weird zig-zaggy mess.

OK, any rules text to back up that it must be a strait line?

[LeonBH]

OK, any rules text to back up that it must be a strait line?

PHB 204: To target something, you must have a clear path to it, so it can't be behind total cover.

PHB 196: A target has total cover if it is completely concealed by an obstacle.

[Cybren]

https://i.imgur.com/oRSlQqn.png
I want to be clear here so i made some diagrams. I think we both agree that the scenario on the left works. Are you arguing that the one on the right also works under the rules?

[LeonBH]

I think he's arguing, by his question of "does the line need to be straight?", that the Fireball can go through the slot and bend to hit the target.

[gloryblaze]

https://i.imgur.com/oRSlQqn.png
I want to be clear here so i made some diagrams. I think we both agree that the scenario on the left works. Are you arguing that the one on the right also works under the rules?

In "Clear Path to the Target", the PHB says:


To target something, you must have a clear path to it, so it can't be behind total cover.

The section on "Cover" says:


A target with total cover can't be targeted directly by an attack or a spell, although some spells can reach such a target by including it in an area of effect. A target has total cover if it is completely concealed by an obstacle.

"Concealed" is no longer a game term in 5e (having been replaced by "obscured"), so we must take "concealed" in this context to being a useage of natural language. "Concealed" is then defined as:


hidden; withdrawn or removed from observation; covered or kept from sight

That definitely seems to imply that if you can't see something, it's concealed from you. And since the source of the concealment in your example is, in fact, an obstacle (a wall in this case), then I would argue that the wizard in second picture you posted does not have line of effect because the target is behind total cover.

If, on the other hand, the target was concealed by anything other than an obstacle - such as Darkness, magical or otherwise - Fireball would still work, as total cover (and thus the breaking of Line of Effect) requires that the target be concealed by an obstacle.

[Arkhios]

Spell attack roll vs AC 15.

Same as you.

IIRC, something like this was the official answer for 3.5 or pathfinder in the exactly same situation, although it wasn't a spell attack roll, for obvious reasons.

[Asmotherion]

DC 15 Spell Attack as suggested above (I say DC instead of AC because I feel it's more of an ability check than an actual attack roll. I am not necesserally right, I just feel like using the wrong term if that makes people feel better :P ). I would even be tempted to make it DC 18-20, deppending on the side of the wall, since an arrow slit is designed to be hard to let things like that pass through (for example, a flamming arrow, that was not fired within 5 feet from it). DC 15 has less than 33% chance of failure for a full caster, and is really more of an annoyance mechanic (Seems easy if you pass it, yet is incredibly frustrating if you fail it due to a bad die roll).

[Unoriginal]

Why make it a check with a DC? It's not how Fireball work, and doing it is contrary to the principle of the spell. If you want to make spell like Fire Bolt harder to hit due to cover, fine, but Fireball explicitly avoid that.

If you want to rule it like this, well, it's your right as a DM, but I don't understand the reasoning.

Again, even if the Fireball explode in the slit, the explosion will go through.

At best, you could ask for a Wis(Perception) check to see if the PC can see through the slit.

[Spore]

I think the main problem with that is that school physics and - to an extent D&D use points as one-dimensional and walls as two-dimensional. Now, even the tiniest flicker of fire has width in all three dimensions, and even the thinest wall has a thickness other than zero. So it's still the DM's call if you can fit the fireball through the arrow slit or not.

Then comes the sight rules. Maybe you simply cannot see the area beyond the arrow slit because of poor illumination? What you are a filthy human instead of an elven wizard? Too bad, your fireball explodes. The good news is that I'd probably rule the wall as damaged in that case.

[Xetheral]

The good news is that I'd probably rule the wall as damaged in that case.

Even though fireball only damages creatures? (It can ignite flammable objects, which presumably are damaged over time as they burn, but only creatures take the initial damage.)

[Lombra]

As Unoriginal said. Shooting inside the slit only requires line of sight, if the fireball were to explode on the external wall, it will still affect the insides since it "spreads around corners" and the slit is a corner within the AoE.

Arrow slits were not designed to prevent fireball attacks in the middle age, they probably would have used other methods if that kind of magic was a thing back then.

[SirGraystone]

No spell attack but if its dark inside maybe a perception check DC 10

[GooeyChewie]

I imagine one would have difficulty seeing through such a small slit at such a distance, so I would probably have the wizard make a Perception check as part of the spell (so not wasting an action, DC depends on the angle). On a success the fireball goes off as intended; on a fail it goes off at the slit (still hitting enemies on the other side if they are within the radius).

[BeefGood]

The caster doesn't have to be able to see through. All that matters is whether there's an unobstructed straight line from the caster to the intended detonation point.
If (a) the caster cannot see inside the structure and (b) the geometry is complex/challenging, (e.g., if the walls are thick, arrow slit is thin) it might not be easy for the caster to figure out where to stand to have that unobstructed straight line. In that case an ability check seems appropriate. Probably perception.
If the caster doesn't get that unobstructed straight line, then the detonation point can be just outside the slit. In that case a jet or wedge of fireball will enter the structure.

[tieren]

Caster needs line of effect, not line of sight.

I would not require any roll to hit the slit, anymore than I would require a roll (other than the dex save) if they wanted to hit any particular spot on the wall, the spell doesn't require it.

Now if the caster said (detonates 20 feet through the slit) and there was an obstruction 5 feet inside, the rule is clear the detonation point becomes the near side of the obstruction.

No rolls are needed, other than the normal dex saves of course.

[Talamare]

Anyone behind the Arrow Slit has +5 to the Saving Throw of Fireball

[rbstr]

They don't have cover if the fireball goes off behind the cover.

If it's an opening and within range you can have the fireball detonate on the other side.
To go otherwise is arbitrary restriction with no guidance on implementation whatsoever. Like, how thin does an opening have to be before you get slapped with one of these extra impediments?

Adding restriction also goes against the targeting guidelines of the spell as you are choosing "a point you choose within range" and the "clear path to target" rule as there is nothing in they way of putting the fireball just on the other side of the arrow slit.

[Tanarii]

That definitely seems to imply that if you can't see something, it's concealed from you. And since the source of the concealment in your example is, in fact, an obstacle (a wall in this case), then I would argue that the wizard in second picture you posted does not have line of effect because the target is behind total cover.You're confusing the issue, along with others using the term "Line of Sight".

Cover has nothing to do with not seeing something. An uninterrupted line with nothing blocking it has nothing to do with sight. Those are incidental effects of an opaque blocking thing, which isn't necessarily the case. Windows and Force Fields allow sight, but still block.

That's why it's important to drop the word "sight" completely from the discussion. Rather, for determining cover / clear path to the target / uninterrupted or unblocked line, use the term "Line of Effect", which isn't officially defined, but at least makes it clear what we're talking about has nothing to do with seeing

See DMG page 251 for the difference between determining Line of Sight, and Cover (aka Line of Effect).

Fireball requires Line of Effect.
Fireball does not require Line of Sight.

[Cybren]

I think that's being overly pedantic Tanarii. Determining if the targeted square has total cover is a useful shorthand for resolving this situation

[Tanarii]

I think that's being overly pedantic Tanarii. Determining if the targeted square has total cover is a useful shorthand for resolving this situation
The person I quoted referenced Total Cover, and then fell back on interpreting "completely concealed" to mean "can't see". Others are using the terms no Line of Sight or can't see when they mean total cover, a non-clear path, a blocked / obstructed path, or no line of effect. Clearly some pedantry is required.

Compare and contrast trying to Fireball something behind a Window or Wall of Force (not possible) vs trying to Fireball something inside a dark room through the doorway (possible), and it quickly becomes clear where people are confusing the issue by using the wrong terms.

[kitanas]

People keep saying to have a clear path you need a straight line. Why? If you were moving to the spot instead, would you need a straight line to say you had a clear path?

[mephnick]

People keep saying to have a clear path you need a straight line. Why? If you were moving to the spot instead, would you need a straight line to say you had a clear path?

Because the fireball moves in a straight line to it's target.

[Tanarii]

People keep saying to have a clear path you need a straight line. Why? If you were moving to the spot instead, would you need a straight line to say you had a clear path?
Because the rules require there be no obstruction be between the PC and the point they are targeting. That means it must be a straight line.

A Clear Path to the Target
To target something, you must have a clear path to it, so it can’t be behind total cover.
If you place an area of effect at a point that you can’t see and an obstruction, such as a wall, is between you and that point, the point of origin comes into being on the near side of that obstruction.

Edit: And also because the way you determine cover is a straight line. Per the DMG for sure, not sure about PHB wording.

[PhoenixPhyre]

People keep saying to have a clear path you need a straight line. Why? If you were moving to the spot instead, would you need a straight line to say you had a clear path?

It's in the definition of Line of Effect (and in the drawings). You have to be able to draw at least one straight line from your space to the target point that is not blocked by total cover. If you can't, you don't have line of effect. If you don't know that you don't, and it's an AoE like fireball, it explodes once it hits the (unseen) obstruction. Note that this does not mean that it will explode on tree branches--only total cover counts.

And for the general topic--as long as you've got a straight shot through the slit, no roll needed. Spells do what they say (and say what they do)--that verbiage (make a touch attack roll, etc) was in previous editions and was not carried over. So it no longer applies by default (without house-rules).

[Tanarii]

So it no longer applies by default (without house-rules).By default and RAW, the DM can call for an attribute check vs a DC of their choice to resolve anything where there something is not automatically successful nor automatically a failure. (Edit: in their judgement.)

That doesn't mean they SHOULD do it in this case. Just that that's the default for the 5e system.

[PhoenixPhyre]

By default and RAW, the DM can call for an attribute check vs a DC of their choice to resolve anything where there something is not automatically successful nor automatically a failure. (Edit: in their judgement.)

That doesn't mean they SHOULD do it in this case. Just that that's the default for the 5e system.

I've always read that as being superseded by the more specific rules in a given spell. That is, the flow looks like:

Q: Is there a defined rule for this action?
Yes: Use that.
No or house-rule: Choose an ability check (with possible proficiency) to resolve the action. Options include No Check Needed (failure) and No Check Needed (success).

Spells are specific exceptions to the general flow--they define their own resolution mechanisms (or rely on others). Saying otherwise is to say that you actually need to roll an attack roll for magic missile, because the DM thinks you should have to aim. That's a valid house-rule, but it's by far not the default rule or even allowed by the default rules.

[Tanarii]

I've always read that as being superseded by the more specific rules in a given spell.


Pretty sure the PHB and DOG DMG are clear it's THE resolution rule. As in, nothing supercedes the ability for the DM to call for a check if they decide it's needed for qquestio
of resolution.

Otoh I agree that generally speaking if resolution is already provided, further resolution usually isn't.

This is just one of those edge cases where some people will see the need for an additional question of resolution, and others won't. Like I said, I've never bothered as a DM, but I certainly wouldn't be bothered if a DM called for a check. That's their job, to adjudicate resolution using the system provided.

Edit:
For reference, here's what the DMG has to say about it:
USING ABILITY SCORES
When a player wants to do something, it's often appropriate to let the attempt succeed without a roll or a reference to the character's ability scores. For example, a character doesn't normally need to make a Dexterity check to walk across an empty room or a Charisma check to order a mug of ale. Only call for a roll if there is a meaningful consequence for failure.
When deciding whether to use a roll, ask yourself two questions:
Is a task so easy and so free of conflict and stress that there should be no chance of failure?
Is a task so inappropriate or impossible- such as hitting the moon with an arrow-that it can't work?
If the answer to both of these questions is no, some kind of roll is appropriate. The following sections provide guidance on determining whether to call for an ability check, attack roll, or saving throw; how to assign DCs; when to use advantage and disadvantage; and other related topics.

So it's pretty clear it's incumbent on the DM to ask themselves these two questions for any question of resolution. Aiming a Fireball through a narrow slit or so that it hits an enemy engaged in melee with an ally but not the ally certainly will qualify in some people's minds.

[BeefGood]

It's in the definition of Line of Effect (and in the drawings). You have to be able to draw at least one straight line from your space to the target point that is not blocked by total cover. If you can't, you don't have line of effect. If you don't know that you don't, and it's an AoE like fireball, it explodes once it hits the (unseen) obstruction.

I get that the caster would do his or her best to attain that straight line. But sometimes the caster will not be sure of success, because vision not perfect, spatial awareness not perfect, perhaps dark inside the room... The caster will find out when the fireball detonates, whether it detonates inside the structure or outside (or more likely within the slit).
But somehow it has to be determined whether the fireball was aimed correctly. That's the DM's job. And if there's some uncertainty, then the DM can resolve that with an ability check. Right?

[PhoenixPhyre]

Pretty sure the PHB and DOG DMG are clear it's THE resolution rule. As in, nothing supercedes the ability for the DM to call for a check if they decide it's needed for qquestio
of resolution.

Otoh I agree that generally speaking if resolution is already provided, further resolution usually isn't.

This is just one of those edge cases where some people will see the need for an additional question of resolution, and others won't. Like I said, I've never bothered as a DM, but I certainly wouldn't be bothered if a DM called for a check. That's their job, to adjudicate resolution using the system provided.

I'd be bothered if and only if the DM thought it was required to make the check. I acknowledge that DMs have the right to adjudicate things however they want, but if they think they're following the default rules and aren't, that means that they haven't been paying attention to the rules.

I don't have a problem with a considered house-rule/ruling: "I know the rules don't require it but feel like we should do it this way." I do have a problem with "this is the way we did it in 3e" or "the rules require it." Because the second is false and the first is irrelevant. And both raise red flags as to the DM's style.

[Cybren]

I get that the caster would do his or her best to attain that straight line. But sometimes the caster will not be sure of success, because vision not perfect, spatial awareness not perfect, perhaps dark inside the room... The caster will find out when the fireball detonates, whether it detonates inside the structure or outside (or more likely within the slit).
But somehow it has to be determined whether the fireball was aimed correctly. That's the DM's job. And if there's some uncertainty, then the DM can resolve that with an ability check. Right?

I will add this: arguing that "if you can fire an arrow through it why not a fireball?" Is a red herring. In the scenario described it's a distant arrow slit. An archer would typically be standing adjacent to one when aiming, not some distance back. You still have the same question with regards to arrows, just a more simple and less controversial solution in the form of granting cover

[Cybren]

I'd be bothered if and only if the DM thought it was required to make the check. I acknowledge that DMs have the right to adjudicate things however they want, but if they think they're following the default rules and aren't, that means that they haven't been paying attention to the rules.

I don't have a problem with a considered house-rule/ruling: "I know the rules don't require it but feel like we should do it this way." I do have a problem with "this is the way we did it in 3e" or "the rules require it." Because the second is false and the first is irrelevant. And both raise red flags as to the DM's style.

It is the default rules though. There's a question of how it works, the DM decides to ask for an ability check. That's... exactly the rules.

[Unoriginal]

Spells that don't require an attack roll are not affected by non-total cover, are they?

[Talamare]

Spells that don't require an attack roll are not affected by non-total cover, are they?

They grant +2 or +5 to the Dex Saving Throw

[GooeyChewie]

Like, how thin does an opening have to be before you get slapped with one of these extra impediments?

That question cuts both ways. How small can a hole be before it doesn’t allow the spell at all? Baseball-sized? Golf ball? Drill hole? Pinprick? Subatomic?

To me, if the opening is questionably small, rather than argue about theoretical lines of effect I’ll have you roll to see if your wizard can find that line of effect mid-combat.

[Talamare]

In the multitudes of tables using strict grid rules, I have always seen Corner to Corner checking for LoS/E

1 Corner from your square to 2 Corners (non overlapping) of the target square.

In this case, you have 0 Corners of the target square.

[Tanarii]

I'd be bothered if and only if the DM thought it was required to make the check. I acknowledge that DMs have the right to adjudicate things however they want, but if they think they're following the default rules and aren't, that means that they haven't been paying attention to the rules.

I don't have a problem with a considered house-rule/ruling: "I know the rules don't require it but feel like we should do it this way." I do have a problem with "this is the way we did it in 3e" or "the rules require it." Because the second is false and the first is irrelevant. And both raise red flags as to the DM's style.The rules don't require it. They allow it, any time the DM thinks there is a question of resolution.

That means it's never a house rule. But calling it a ruling is fair. It's pretty much exactly what 5e devs meant by rulings not rules. They provided the mechanic and told us what it's for, and it's up to the DM to decide if it's necessary to use under these, or any other, circumstances.

[PhoenixPhyre]

It is the default rules though. There's a question of how it works, the DM decides to ask for an ability check. That's... exactly the rules.

So if you say "I'm going to hit him with my sword" and the DM says "make an intelligence check to see if you hit" (and there are no spells or other effects that require doing so), the DM is following the default rules just fine and you have no cause to wonder what's going on?

I reject this. The "choose any ability and a DC" comes into play in the absence of more specific rules. That's what specific beats general means. If there's a specific rule, the general rule that covers the same ground is overridden and no longer applies. Spells are all specific rules. They override the "decide what ability check to make and a DC" general rule by specifying resolution mechanics. Adding more is neither fair nor is it following the general rules. It's allowed (Rule 0) but is a house-rule at best.

[Tanarii]

(Edit: Sorry this was kinda snarky. Getting rid of it. See my post 2 below)

[Xetheral]

I don't have a problem with a considered house-rule/ruling: "I know the rules don't require it but feel like we should do it this way." I do have a problem with "this is the way we did it in 3e" or "the rules require it." Because the second is false and the first is irrelevant. And both raise red flags as to the DM's style.

Interpreting a spell in line with how it worked in previous editions isn't irrelevant if you're still playing in the same game world and value setting consistency. So, for example, I require attack rolls if careful aiming of a fireball is required, and I permit fireballs to damage objects (e.g. catapults), because I want siege warfare in my world to be consistent in my setting even though I'm now playing a different edition.

These were not trivialities either: homebrew fireball variants in 3.0 and 3.5--ballistic fireball and explosive fireball--played a major role in the way a particular nation designed their military tactics. If I permitted explosive fireball (which fills a constant volume) to go through arrow slits at will, it would be too simple to wipe out defenders in an enclosed space. Similarly, if ballistic fireball couldn't damage objects, it's usefulness for counterbattery fire would be greatly reduced, and it's ability to capture infrastructure intact would remove one of the important constraints on it's use against soft targets.

So at my table I require attack rolls to place a fireball through an arrow slit and I permit fireball to damage object. Whether or not it is RAW doesn't really matter to me, because the in-word lore about how fireball works (and the consequences for military tactics and fortification design) was established for my setting long ago.

[Tanarii]

It's worth noting that if PhoenixPhyre is making this argument, he's got a good point: if there's already a rule for resolving something, the DM shouldn't need a rule to resolve the exact same thing.

That's a solid argument, especially if you apply specific and general to it.

But the point here though is that in the case of placing a fireball with exact precision may not be the same question of resolution already answered by the saving throw. Or it might. Up to the DM though. If it's not, there's a general rule for resolution he can apply.

[PhoenixPhyre]

Interpreting a spell in line with how it worked in previous editions isn't irrelevant if you're still playing in the same game world and value setting consistency. So, for example, I require attack rolls if careful aiming of a fireball is required, and I permit fireballs to damage objects (e.g. catapults), because I want siege warfare in my world to be consistent in my setting even though I'm now playing a different edition.

These were not trivialities either: homebrew fireball variants in 3.0 and 3.5--ballistic fireball and explosive fireball--played a major role in the way a particular nation designed their military tactics. If I permitted explosive fireball (which fills a constant volume) to go through arrow slits at will, it would be too simple to wipe out defenders in an enclosed space. Similarly, if ballistic fireball couldn't damage objects, it's usefulness for counterbattery fire would be greatly reduced, and it's ability to capture infrastructure intact would remove one of the important constraints on it's use against soft targets.

So at my table I require attack rolls to place a fireball through an arrow slit and I permit fireball to damage object. Whether or not it is RAW doesn't really matter to me, because the in-word lore about how fireball works (and the consequences for military tactics and fortification design) was established for my setting long ago.

I don't particularly mind if it's a considered step, announced in advance (like any other house-rule/variant rule). That is, if a DM said "we're going to require an attack vs a fixed AC for shooting through a slit", then that's ok. There's a reason for it and it's known. Springing it on players who are presuming that their actions do what the book says is not ok in my opinion (at least without letting them take back their action and do something different). I care that the rules are known in advance, not that any specific rule is in play. I wouldn't even care if the AC varied, as long as I knew that that's what I'm doing and can plan accordingly.




But the point here though is that in the case of placing a fireball with exact precision may not be the same question of resolution already answered by the saving throw. Or it might. Up to the DM though. If it's not, there's a general rule for resolution he can apply.

That point is the exception that swallows the rule. Everything can be in question. But the presumed default ruling is to expect the spell (or ability)'s text to provide all the restrictions that apply. Going beyond that (especially in a way that nerfs a player's actions) feels wrong to me. The DM can do anything. In all reality, the DMG does not contain any rules. It contains suggestions. All the rules are in the PHB. And there it specifically declines to place any further restrictions on casting spells through slits. So anything else is a house-rule.

[JNAProductions]

The thing is, this is an unusual situation. I'm not going to say my ruling is the only possible one, or that it even NEEDS a ruling, but I don't think it's unreasonable to call for a check when you're trying an exactingly precise maneuever with a spell.

I'd agree that it'd be a step too far to require a check just to place it right on an open area, since adventurers are assumed to be competent. But "hitting" an opening that's only an inch or two wide at 60' seems more dificult than just placing a spell on the right spot.

[Tanarii]

That point is the exception that swallows the rule. Everything can be in question. But the presumed default ruling is to expect the spell (or ability)'s text to provide all the restrictions that apply. Going beyond that (especially in a way that nerfs a player's actions) feels wrong to me. The DM can do anything. In all reality, the DMG does not contain any rules. It contains suggestions. All the rules are in the PHB. And there it specifically declines to place any further restrictions on casting spells through slits. So anything else is a house-rule.Your argument is solid on specific beats general, provided it's the same resolution. But it is not a house-rule for the DM to apply the general rule if they deem anything to not be covered by a specific rule for resolution already, or if something that normally doesn't have a rule for resolution (ie it just happens) needs to be resolved. That's their job, and there is a rule for it. Every time you call the DM doing their job and using the rule provided for it, per the DMG, a house-rule, you undermine your own argument.

[PhoenixPhyre]

Your argument is solid on specific beats general, provided it's the same resolution. But it is not a house-rule for the DM to apply the general rule if they deem anything to not be covered by a specific rule for resolution already, or if something that normally doesn't have a rule for resolution (ie it just happens) needs to be resolved. That's their job, and there is a rule for it. Every time you call the DM doing their job and using the rule provided for it, per the DMG, a house-rule, you undermine your own argument.

The DMG does not have rules. It has suggestions. Any "basic rule" that you find there is a nullity--DMs don't have rules. They have default settings that they can choose to change. What I'm saying is that this is a change from the default.

The rules are only in the PHB. And the general rule there (definition of line of effect) covers the situation, and there are no exceptions. I don't see what's so hard about this.

1) A rule exists that covers the situation (Page 202, PHB--"When a character casts any spell, the same basic rules are followed, regardless of ... the spell's effects."). This is casting a spell, so regardless of the effect of the spell, the rules are followed. This is a global rule, so it covers any use of a spell.
2) A sub-rule exists: Targets->A clear path to the target (PHB 204). This covers obstructions in the way, so other rules are precluded (by default--this covers all situations).
3) The spell does not modify these basic rules (text of the fireball spell), so the basic rules apply.
4) Done.

DMs can override this default flow, but that's not the default then, by design. And it should be communicated in advance, clearly. Otherwise it's a stealth-nerf, without even the honesty to call it what it is.

Note that the sidebar for ability checks in the DMG (pg 237) doesn't have "placing a spell accurately"--that's presumed in the ability to cast a spell and in the ability-based DC of resisting the spell's effects. You're double-dipping against an arbitrary DC, just to nerf an ability without saying you're nerfing it. And I find that obnoxious and a red flag for a DM.

Arguments from "it makes sense" are isomorphic to "I don't want it to work" in my experience. If it was a spell that required precision placement, then it would require an attack roll. No other spell is subjected to this--does magic missile have to make that attack roll? Does an arrow? Yes, they have 3/4 cover, but that explicitly does not affect placement. Only dex saves when the line between the creature and the point of origin is partially obstructed.

I could see "you can't do that--it will explode on the surface of the obstruction" and "you can do that fine"; "During this game we'll use <attack roll placement rule>" is also fine if communicated in advance. Doing it on the fly and not letting the player change their mind doesn't sit well with me. The DM is allowed to do it (because he's allowed to do anything), but he shouldn't.

[Tanarii]

The DMG does not have rules. It has suggestions. Any "basic rule" that you find there is a nullity--DMs don't have rules. They have default settings that they can choose to change. What I'm saying is that this is a change from the default.

The rules are only in the PHB. And the general rule there (definition of line of effect) covers the situation, and there are no exceptions. I don't see what's so hard about this.The DMG has many rules. Your claim is provably wrong by cracking it open and leafing through it briefly.

Besides, the PHB also has the exact same rule on page 174:
The DM calls for an ability check when a character or monster attempts an action (other than an attack) that has a chance of failure. When the outcome is uncertain, the dice determine the results.

The DMG has several pages worth telling them how to do that, starting on page 237.

It is very clearly not a house-rule for a DM to decide any outcome they feel needs it to have an ability check for resolution. Ruling? Sure. House-rule? Absolutely not.

[Cybren]

The DMG is a rulebook. It contains rules. Even using your artificially narrow definition of "rule" the section on magic items qualifies as rules.

[PhoenixPhyre]

I can see that my sense of what the rules mean is not generally shared. I still feel strongly that DMs should not do this without good justification and without stating it in advance. Because I hate having surprises sprung on me out of someone's sense of "what makes sense." I've had too many bad experiences with that.

[LeonBH]

I think that if the DM doesn't want their NPCs and monsters to get hit by a Fireball, they will not get hit by a Fireball. If they think an arrow slit will protect their monsters, then it will.

It is unfair to the caster, but such is the reality of 5e.

[Xetheral]

It is very clearly not a house-rule for a DM to decide any outcome they feel needs it to have an ability check for resolution. Ruling? Sure. House-rule? Absolutely not.

While I agree with you completely, it's probably worth pointing out that many (if not most) posters in the Ability-Check-to-Identify-a-Spell-Being-Cast thread disagreed with that position. Some went so far as to say it is a houserule to use an ability check to resolve anything other than the specific examples given. I suspect part of the problem is that there is no community consensus on the dividing line between a ruling and a houserule.

[Unoriginal]

The thing is, this is an unusual situation. I'm not going to say my ruling is the only possible one, or that it even NEEDS a ruling, but I don't think it's unreasonable to call for a check when you're trying an exactingly precise maneuever with a spell.

I'd agree that it'd be a step too far to require a check just to place it right on an open area, since adventurers are assumed to be competent. But "hitting" an opening that's only an inch or two wide at 60' seems more dificult than just placing a spell on the right spot.

Fireball's an AoE. You select any point of the foe (or near the foe) that you can see through the slit, the ball goes there, then it explodes.

You're not aiming.

[Coffee_Dragon]

I suspect part of the problem is that there is no community consensus on the dividing line between a ruling and a houserule.

Sure there is.

Whenever I want something to work a certain way and the rules are unclear or silent on this point, then playing like this is a ruling. Effecting rulings is creative and part of a DM's natural duties. I do this reasonably and sensibly.

Whenever I don't want something to work a certain way and the rules are unclear or silent on this point, then playing like this is a house rule. Effecting house rules is arbitrary and springs a nasty surprise on players. Other people do this stubbornly and dubiously.

This distinction is widely applied in this forum.


Fireball's an AoE. You select any point of the foe (or near the foe) that you can see through the slit, the ball goes there, then it explodes.

This doesn't exclude it from potential DM adjudication, though. For instance, an AoE-related form of adjudication I assume to be fairly common is to say you can't make it fall neatly between frontline fighters, even when using a grid.

[GooeyChewie]

I could see "you can't do that--it will explode on the surface of the obstruction"...

Which makes it as much a stealth BOOST as nerf, doesn’t it? I mean, the wizard is trying to cast fireball through a wall on the premise that an arrow slit - which is probably shuttered or occupied - makes the line of effect “unobstructed.” As far as I’m concerned, I’m allowing you a free chance to look for something instead of pointing out the implausibility of such a line of effect and straight up telling you no. And yes, I’ll let the wizard know the deal before he actually casts the spell.

[Cybren]

Fireball's an AoE. You select any point of the foe (or near the foe) that you can see through the slit, the ball goes there, then it explodes.

You're not aiming.

That's dependent on if you view the aiming as abstracted into the damage roll and saving throw and the general game rule assumption to not bog things down with too much detail in the general use case of people fighting in large dungeons segmented into 5ft increments. The description of the spell literally states that it stretches out from your finger in a straight line, so it's not absurd to rule that in particular corner case scenarios the wizard would have to be more careful with how they place a fireball. How that gets adjudicated is a matter of the tone of the campaign, how your table interprets how magic functions, and whether other things that will vary from table to table.

[Tanarii]

While I agree with you completely, it's probably worth pointing out that many (if not most) posters in the Ability-Check-to-Identify-a-Spell-Being-Cast thread disagreed with that position. Some went so far as to say it is a houserule to use an ability check to resolve anything other than the specific examples given. I suspect part of the problem is that there is no community consensus on the dividing line between a ruling and a houserule.
Probably including me, especially pre-Xantathars. Participating in this forum has changed my views, as I came to understand the design intent of 5e, particularly the ability check system. Certainly by the time Xanathar's came out, my position was slightly revised to be something like "they clearly didn't intend it to be possible, but yes you can always assign a check for anything if you want".

And my position here is similar. I don't think requiring a check to precisely place a Fireball is required, be it squeezing it thru a arrow slit or hitting someone next to an ally without hitting the ally. I think if the player objects to such a ruling, they should tell the DM that (very politely) and then discuss it with them afterwards. I would not personally object to it, but I can totally understand why a player might. I can understand why PhoenixPhyre does.

But I also think it falls precisely within the DM's job of determining what needs adjudication, and if they need to use the provided mechanic to do it. No house-rules are involved. I'm saying it's a ruling, and there's a fall-back mechanic for exactly such rulings. Not that it's a good ruling, nor that everyone should like it.


Sure there is.

Whenever I want something to work a certain way and the rules are unclear or silent on this point, then playing like this is a ruling. Effecting rulings is creative and part of a DM's natural duties. I do this reasonably and sensibly.

Whenever I don't want something to work a certain way and the rules are unclear or silent on this point, then playing like this is a house rule. Effecting house rules is arbitrary and springs a nasty surprise on players. Other people do this stubbornly and dubiously.

This distinction is widely applied in this forum.lol nailed it :smallbiggrin:

[JNAProductions]

Also, just for the information, I'm sure as hell not saying "AC 15 attack roll to get past the arrow slit" AFTER they declare their use of the spell. It'll be said as soon as they declare their action, and if they want to try something else, they're free to.

[Xetheral]

Sure there is.

Whenever I want something to work a certain way and the rules are unclear or silent on this point, then playing like this is a ruling. Effecting rulings is creative and part of a DM's natural duties. I do this reasonably and sensibly.

Whenever I don't want something to work a certain way and the rules are unclear or silent on this point, then playing like this is a house rule. Effecting house rules is arbitrary and springs a nasty surprise on players. Other people do this stubbornly and dubiously.

This distinction is widely applied in this forum.

Very well said. I concede the point. :)

[BeefGood]

To anyone who does not use attack role/ability check in this situation—how do you handle it? How do you determine whether there is an unobstructed path to the intended detonation point?

[gloryblaze]

To anyone who does not use attack role/ability check in this situation—how do you handle it? How do you determine whether there is an unobstructed path to the intended detonation point?

Get out a ruler. If there's at least one straight line from the caster to the point they chose that passes through the arrow slit, it works. If there's not, the fireball detonates inside the arrow slit, spilling out on both sides.

[Tanarii]

Get out a ruler.Theatre of the Mind.

[Cybren]

Presumably, unless mirrors are involved, if they can see the place they want to target on the other side of the arrow slit they have an unobstructed straight line to it. The question is, can they accurately put the line there. That's why it's a corner case that doesn't have a correct ruling. It's not wrong to say they can because the rules don't directly state ever that aiming is an issue, but its also not wrong to say this is a particular special corner case and it's possible to mess up.

[Talamare]

To anyone who does not use attack role/ability check in this situation—how do you handle it? How do you determine whether there is an unobstructed path to the intended detonation point?

Corner to Corner Line of Sight produce very clean results.

Aka
Choose 1 Corner in your Square, you must be able to draw 2 of your target without overlapping.

In this case, you aren't able to draw to any Corners (or arguably 1 Corner)

So you can't shoot it thru the slit, but you may explode it at the slit itself. Granting +5 Dex to Saves to everyone behind the Arrow Slit.

[Tanarii]

It's certainly an interesting question, because it combines two things:

1) You can't see the end point location clearly, so how do you target it in the first place? Basically, this is the same problem as targeting a dark room through the open doorway. Do you just declare a distance, or a distance past the last location you last saw? How does your character judge either distance in the first place? It's not like PCs can take a glance and say "that's 50ft, based on counting squares" (battlemat) or "DM telling me" (ToTM). Nor can they bust out a measuring tape.

2) It's asking for incredible precision, far beyond either "template overlaps the square their enemy is somewhere in" (battlemat) or "DM judgement on how many enemies can be included in the area of effect" (ToTM). Both of which are metagame anyway, same as above. ie it's not like the PC can bust out a template or check with the DM.

In fact, using battlemats in general imply a far greater level or precision than the abstraction actually does in the first place. That becomes much more evident if you play with TotM for a while. (Not saying that TotM doesn't come with it's own lack of precision issues. I had to abandon a purely TotM approach because of exactly that, so now I mix and match depending on needs.)


Corner to Corner Line of Sight produce very clean results.

Aka
Choose 1 Corner in your Square, you must be able to draw 2 of your target without overlapping.

In this case, you aren't able to draw to any Corners (or arguably 1 Corner)

So you can't shoot it thru the slit, but you may explode it at the slit itself. Granting +5 Dex to Saves to everyone behind the Arrow Slit.
If you can't draw to any corners, isn't that complete cover, under the DMG rules? That'd prevent damage completely.
(I'm assuming this particular ruling is based on application the DMG miniatures rules.)

[Beelzebubba]

Arguments from "it makes sense" are isomorphic to "I don't want it to work" in my experience. If it was a spell that required precision placement, then it would require an attack roll. No other spell is subjected to this--does magic missile have to make that attack roll? Does an arrow? Yes, they have 3/4 cover, but that explicitly does not affect placement. Only dex saves when the line between the creature and the point of origin is partially obstructed.

I could see "you can't do that--it will explode on the surface of the obstruction" and "you can do that fine"; "During this game we'll use <attack roll placement rule>" is also fine if communicated in advance. Doing it on the fly and not letting the player change their mind doesn't sit well with me. The DM is allowed to do it (because he's allowed to do anything), but he shouldn't.

I'm in line with this.

To me, it comes down to: the spellcaster sees an arrow slit in the wall. Can they see through to what's behind, due to it being lit or the slit being big enough to see the motion of the people behind it - and it's a clear enough target for a Magic Missile or an arrow? Sure, just cast.

But, if they see an arrow slit that's difficult to fully perceive (due to distance, dark stone, being in shade, the opening being very thin, etc.), at mid-to-long range, and it's unlit from behind so you can't actually see inside (so Magic Missiles can't target anything, and arrow attacks are at Disadvantage)? The caster is making a guess as to which point of the blackness he's targeting is actually inside the castle or perhaps accidentally the surface of the stone, so I can see a Perception check being called here. And DC 15 seems like a decent enough DC for most cases at long range, but if conditions are really bad - foggy, at night, etcetera - I could occasionally see a DC 20.

If it fails, the detonation happens outside, the fireball radius is partially outside the castle wall, and the targets inside get the standard 3/4 +5 Cover Bonus to the save.

I see it that way because the caster's perception can fail them, and the point that they focus on may be the stone rather than the slit despite their best intent. Just like any one of us can, say, misread a street sign at night.

But, like anything else, we generally talk through this stuff at the table. Some external circumstances affect those spells too, and we try to apply those fairly and evenly to all classes when appropriate. We don't grant superhuman perfection to spellcasters just because they don't have to roll for some of their abilities. And we are open to discussing things as a table after the game to air out ruling disagreements.

[gloryblaze]

Theatre of the Mind.

The question was "how do you handle it". My group uses graph paper in person or Roll20 during university.

[Strangways]

He doesn't need to see everyone in the blast radius, he just need to see the point at which the fireball detonates so I don't see that as a problem. Theoretically the fireball might not fit through the arrow slit, in which case I'd say it might detonate on the wrong side of the arrow slit, and the people on the far side would get +5 to their DEX save per the rules for 3/4 cover. I'd tell that to the players up front so he could change his mind about whether to cast it. Either way, I don't see any basis for telling him to make an attack roll.

[LeonBH]

To anyone who does not use attack role/ability check in this situation—how do you handle it? How do you determine whether there is an unobstructed path to the intended detonation point?

There is no obstruction. It's an open hole in the wall, which means things can pass through the hole unobstructed.

[Beelzebubba]

There is no obstruction. It's an open hole in the wall, which means things can pass through the hole unobstructed.

That's being rather simplistic. What about an arrow slit in an obsidian wall at night that has no backlight at long range? Does it automatically 'know' to go through? If so, why?

[LeonBH]

That's being rather simplistic. What about an arrow slit in an obsidian wall at night that has no backlight at long range? Does it automatically 'know' to go through? If so, why?

That's because Fireball is a simple spell. It doesn't aim, it just happens.

"Long range" is only 150ft, the max range of Fireball. That is only 40% the length of a football field. Things do not go invisible at that distance.

You can see stars in the sky. Those things occupy 0.0024 arcseconds in your field of view. You would see the same object if a glowing orb were 10 centimeters tall and 45 meters away (which is about the meter equivalent of 150ft). Ergo, you can see a 10 centimeter tall object (or slit) that is at the max distance of Fireball from you.

Darkness does not affect spell saves. Presumably, the caster wanting to cast through the slit would already know where the slit is. Otherwise, it's fair to ask a perception check (at disadvantage) to spot it. But once it's seen, the caster doesn't need to roll anything because it's a magical spell that always hits (but provides a Dex save).

[Tanarii]

The question was "how do you handle it". My group uses graph paper in person or Roll20 during university.
Oh. My bad. Sorry.

[Lord Vukodlak]

That's because Fireball is a simple spell. It doesn't aim, it just happens.

"Long range" is only 150ft, the max range of Fireball. That is only 40% the length of a football field. Things do not go invisible at that distance.

You can see stars in the sky. Those things occupy 0.0024 arcseconds in your field of view. You would see the same object if a glowing orb were 10 centimeters tall and 45 meters away (which is about the meter equivalent of 150ft). Ergo, you can see a 10 centimeter tall object (or slit) that is at the max distance of Fireball from you.

Darkness does not affect spell saves. Presumably, the caster wanting to cast through the slit would already know where the slit is. Otherwise, it's fair to ask a perception check (at disadvantage) to spot it. But once it's seen, the caster doesn't need to roll anything because it's a magical spell that always hits (but provides a Dex save).

The explosion doesn't just appear at the point of origin the caster shoots something from his finger that explodes at the point of detonation. "A bright streak flashes from your pointing finger" So presumably if there was an invisible obstruction between you and the target space the fireball would detonate early... or do nothing 5e isn't clear on that point.

Normally a fireball is targeting a square then exploding from that point, if your off by two or three feet it doesn't matter the effective area is still basically the same. Area spells effect a big area so aiming normally shouldn't matter, but an arrow slit is about two inches wide, the fact it only grants a +5 cover bonus to AC is incredibly generous.

Back in 3rd edition requiring an attack roll to shoot a fireball through an arrow slit was actually in the spell description. Even if your being forced to make an attack roll to fire through an incredibly narrow opening a fireball is still vastly more useful in that situation then any ranged weapon. That's not being unfair to casters its being fair to non-casters, its making fortifications a challenge to overcome and not a speed bump.

Look up pictures of RL arrow slits then come back and say wizards shouldn't have a problem targeting a fireball through them.

[Beelzebubba]

Presumably, the caster wanting to cast through the slit would already know where the slit is. Otherwise, it's fair to ask a perception check (at disadvantage) to spot it.

That was the entire point of the discussion - the part after your presumption.

Just because they see the slot doesn't mean they see through it, especially at long range. There are a lot of reasons they could accidentally target a point that they assume goes through and doesn't.

[LeonBH]

The explosion doesn't just appear at the point of origin the caster shoots something from his finger that explodes at the point of detonation. "A bright streak flashes from your pointing finger" So presumably if there was an invisible obstruction between you and the target space the fireball would detonate early... or do nothing 5e isn't clear on that point.

That is semantics. The thing that streaks from the caster's pointing finger requires no attack roll or ability check to hit the point of origin the caster chooses. Once they choose a point of origin, the explosion happens there.


Normally a fireball is targeting a square then exploding from that point, if your off by two or three feet it doesn't matter the effective area is still basically the same. Area spells effect a big area so aiming normally shouldn't matter, but an arrow slit is about two inches wide, the fact it only grants a +5 cover bonus to AC is incredibly generous.

Back in 3rd edition requiring an attack roll to shoot a fireball through an arrow slit was actually in the spell description. Even if your being forced to make an attack roll to fire through an incredibly narrow opening a fireball is still vastly more useful in that situation then any ranged weapon. That's not being unfair to casters its being fair to non-casters, its making fortifications a challenge to overcome and not a speed bump.

This is 5th edition, not 3rd edition. The spell description of Fireball no longer includes that stipulation.


Look up pictures of RL arrow slits then come back and say wizards shouldn't have a problem targeting a fireball through them.

Read the rules. Come back after you've understood they aren't meant to be simulationist.



That was the entire point of the discussion - the part after your presumption.

Exactly. So since the slit is seen, then the spell goes through since it is an unobstructed hole.


Just because they see the slot doesn't mean they see through it, especially at long range. There are a lot of reasons they could accidentally target a point that they assume goes through and doesn't.

If they target a point incorrectly, then they have not seen the slit. We're assuming they already see their target, which means they can hit it.

"Long range" is not that far away for Fireball.

And finally, all the reasons that causes the Fireball to go off incorrectly violate the premise of the spell, which is that the caster can precisely choose the point of origin of Fireball. In other words, it's just a way to make point-of-origin spells a worse option.

[RazorChain]

No attack roll required. If you can see it, you can hit it.

I like that rule. Next time I'm going to detonate a fireball when it hits somebodies eyeball or up their nose. Dodge that you villain! Instant disadvantage on their saving throw!

[LeonBH]

Instant disadvantage on their saving throw!

Not unless they are restrained or you have Heightened Spell.

[Malifice]

Why make it a check with a DC? It's not how Fireball work, and doing it is contrary to the principle of the spell. If you want to make spell like Fire Bolt harder to hit due to cover, fine, but Fireball explicitly avoid that.

If you want to rule it like this, well, it's your right as a DM, but I don't understand the reasoning.

Again, even if the Fireball explode in the slit, the explosion will go through.

At best, you could ask for a Wis(Perception) check to see if the PC can see through the slit.

You're hurling (magically propelling) a bead of fire through a 2 inch wide slit, hoping for it to detonate on the other side of said slit.

If the bead of fire hits the outside wall, the fireball detonates earlier.

Thats the reasoning.

[georgie_leech]

You know what also goes unerringly forward until it hits something that interrupts it? A laser pointer. If I handed a laser pointer to a Wizard and told them to point it at an arrow slit 60 feet away and then turn it on, would it automatically go through? Or would some sort of check be needed to see if it went through on the first try, without shining on the wall at all?

That seems pretty analogous to the finger pointing; the attack roll represents "did the wizard point at the precise location when the spell went off?" An inch or two to the side doesn't make much of a difference most of the time, but this sure seems a time when it does.

[Knaight]

I'd probably just give +5 to the reflex saves, and stick with the rules. If I somehow end up GMing D&D it's because my players wanted to do it, and this seems to be the way 5e favors handling it.


Whenever I want something to work a certain way and the rules are unclear or silent on this point, then playing like this is a ruling. Effecting rulings is creative and part of a DM's natural duties. I do this reasonably and sensibly.

Whenever I don't want something to work a certain way and the rules are unclear or silent on this point, then playing like this is a house rule. Effecting house rules is arbitrary and springs a nasty surprise on players. Other people do this stubbornly and dubiously.

This distinction is widely applied in this forum.
While I do appreciate the snark, and would even say that it is widely applied there are competing definitions. Most notably, there's the definition that if the DM has to make any judgement call whatsoever it's a house rule, which is bad, which is why 3.5 is a better system.

[LeonBH]

You know what also goes unerringly forward until it hits something that interrupts it? A laser pointer. If I handed a laser pointer to a Wizard and told them to point it at an arrow slit 60 feet away and then turn it on, would it automatically go through? Or would some sort of check be needed to see if it went through on the first try, without shining on the wall at all?

That seems pretty analogous to the finger pointing; the attack roll represents "did the wizard point at the precise location when the spell went off?" An inch or two to the side doesn't make much of a difference most of the time, but this sure seems a time when it does.

A laser pointer is hard to point with by itself. Considering the accuracy of Fireball (not needing to roll to hit), it would be more accurate to give them a laser scope.

[georgie_leech]

A laser pointer is hard to point with by itself. Considering the accuracy of Fireball (not needing to roll to hit), it would be more accurate to give them a laser scope.

Fine then. A laser scope; turn it on, and have it go right through the arrow slit 60 feet away without touching the wall at all. Again, is that something the Wizard can do automatically? For the sake of their being mechanical consequences, say there's a bet where the prize is 100 gold. Do Wizards just get 100 gold in this scenario? Or would there be some sort of check involved? What if they were a Fighter instead?

[Talamare]

If you can't draw to any corners, isn't that complete cover, under the DMG rules? That'd prevent damage completely.
(I'm assuming this particular ruling is based on application the DMG miniatures rules.)

DMG states that if the person is behind total cover but somehow its still possible then it's 3 quarters. Pg251

[Spore]

My group uses graph paper in person or Roll20 during university.

You do you but I feel graph paper is slight overkill. It's like butchering the theater of mind with surgical precision.

[LeonBH]

Fine then. A laser scope; turn it on, and have it go right through the arrow slit 60 feet away without touching the wall at all. Again, is that something the Wizard can do automatically? For the sake of their being mechanical consequences, say there's a bet where the prize is 100 gold. Do Wizards just get 100 gold in this scenario? Or would there be some sort of check involved? What if they were a Fighter instead?

Yes. Same for Fighters.

[BeefGood]

I'd like to know how people handle the case of limited information available to the caster. For the sake of this argument, let's assume that if the caster can see their target, the caster can hit it. Let's also not worry about range. Everything's within 150'.

A caster, standing outside a structure, wishes to detonate a fireball inside the structure. On the wall of the structure, the caster can see a dark rectangular area, but he can't identify it any better than that (at least not at the start of the scenario). It could be...
*black paint on the outer face of the wall, or
*a shadowed recess in the wall, such that the caster is actually viewing bricks that are somewhat inset from the outer face of the wall
*an opening through the wall, such that the caster is actually viewing closed dark-colored wooden shutters attached to the wall's interior face (or equivalently, a dark curtain hung over the opening's interior face)
*an opening through the wall and into the structure, such that the caster is actually viewing the opposite, dark-colored, interior wall of the structure, or
*something else.

How would you, as either player or DM, play out this scenario?

[LeonBH]

I'd like to know how people handle the case of limited information available to the caster. For the sake of this argument, let's assume that if the caster can see their target, the caster can hit it. Let's also not worry about range. Everything's within 150'.

A caster, standing outside a structure, wishes to detonate a fireball inside the structure. On the wall of the structure, the caster can see a dark rectangular area, but he can't identify it any better than that (at least not at the start of the scenario). It could be...
*black paint on the outer face of the wall, or
*a shadowed recess in the wall, such that the caster is actually viewing bricks that are somewhat inset from the outer face of the wall
*an opening through the wall, such that the caster is actually viewing closed dark-colored wooden shutters attached to the wall's interior face (or equivalently, a dark curtain hung over the opening's interior face)
*an opening through the wall and into the structure, such that the caster is actually viewing the opposite, dark-colored, interior wall of the structure, or
*something else.

How would you, as either player or DM, play out this scenario?

The caster should investigate the wall to know that it is an opening. Once he has identified it is, he may cast Fireball through it.

If he casts Fireball in place without prior investigation though, then he may pick a point of origin on the other side of the dark wall. If it's an opening, the Fireball will pass through it and detonate on the point of origin you chose. If it's not an opening, the Fireball detonates on the near side of the wall.

PHB 204: "If you place an area of effect at a point that you can't see and an obstruction, such as a wall, is between you and that point, the point of origin comes into being on the near side of that obstruction"

That is to say, you can place an area of effect on the other side of an obstacle, even if you can't see where it would explode.

[GooeyChewie]

Read the rules. Come back after you've understood they aren't meant to be simulationist.

Exactly. So since the slit is seen, then the spell goes through since it is an unobstructed hole.
I agree the rules are not simulationist, but it can be helpful to have an idea of what you are calling an “unobstructed hole.”

If we were dealing with simulationist rules, then the wizard would have to make a Perception check to even see the arrow slit, at disadvantage if you are under fire. Arrows move too fast to let you precisely trace their origins, so no help there. Once you do find the arrown slit, you’ll have to stand directly in the field of fire to cast the spell. And you certainly won’t be able to see in, because the interior is kept purposefully dimmer than the exterior to prevent exactly that. You’ll have no idea of the interior layout or how many enemies might be inside.

Since we aren’t dealing with simulationist rules, I’m willing reduce all of that to “Roll Perception to see if you can determine a viable line of effect.”



If they target a point incorrectly, then they have not seen the slit. We're assuming they already see their target, which means they can hit it.

I think our disconnect stems from this point. You assume the wizard already sees the target; I assume the wizard cannot see inside the slit (because that’s how arrow slits work) and thus cannot guarantee a line of effect without double-checking. Making the wizard pass a Perception check to find a nigh-impossible line of effect is not a way to make point-of-origin spells worse; it’s a way to make them way better by taking what by all rights should be an obstruction (a wall) and giving the wizard a relatively easy way to overcome it.

[LeonBH]

I agree the rules are not simulationist, but it can be helpful to have an idea of what you are calling an “unobstructed hole.”

If we were dealing with simulationist rules, then the wizard would have to make a Perception check to even see the arrow slit, at disadvantage if you are under fire. Arrows move too fast to let you precisely trace their origins, so no help there. Once you do find the arrown slit, you’ll have to stand directly in the field of fire to cast the spell. And you certainly won’t be able to see in, because the interior is kept purposefully dimmer than the exterior to prevent exactly that. You’ll have no idea of the interior layout or how many enemies might be inside.

Since we aren’t dealing with simulationist rules, I’m willing reduce all of that to “Roll Perception to see if you can determine a viable line of effect.”

You should further reduce that to "can hit through the slit with no perception" (read below to see my explanation)


I think our disconnect stems from this point. You assume the wizard already sees the target; I assume the wizard cannot see inside the slit (because that’s how arrow slits work) and thus cannot guarantee a line of effect without double-checking. Making the wizard pass a Perception check to find a nigh-impossible line of effect is not a way to make point-of-origin spells worse; it’s a way to make them way better by taking what by all rights should be an obstruction (a wall) and giving the wizard a relatively easy way to overcome it.

I assume that the Wizard sees the slit, not what is inside. It doesn't matter if they can't see what is inside the slit because of two reasons:

1. They can detonate the Fireball at the slit, and the explosion bends around corners
2. They can place the point of origin behind the slit, even if they can't see where they're putting it, due to the targeting rules

[Vogie]

A Wizard is standing somewhere, and wants to fire a Fireball through an arrow slit, about 60' away. He aims to have it explode on the other side of the arrow slit.




I think our disconnect stems from this point. You assume the wizard already sees the target; I assume the wizard cannot see inside the slit (because that’s how arrow slits work) and thus cannot guarantee a line of effect without double-checking. Making the wizard pass a Perception check to find a nigh-impossible line of effect is not a way to make point-of-origin spells worse; it’s a way to make them way better by taking what by all rights should be an obstruction (a wall) and giving the wizard a relatively easy way to overcome it.


... You assume your wizard can't see something 60 feet away? Do they need corrective lenses?
In the DMG, Normal sight is 2 miles illuminated, 1 mile in the rain. Even racial darkvision is normally 60'.

Arrow Slits are traditionally in a cross or "t" formation, from 3-9 ft in height (and possibly length), width varies.
http://c8.alamy.com/comp/BYAEDP/arrow-slit-windows-in-a-wall-of-the-tower-of-london-BYAEDP.jpg

I just want you to realize that your argument is your wizard can't see a person-sized (or at least halfling-sized) literal x-marks-the-spot target at less than half the range of fireball (150 ft) and the goal isn't to hit a person you can see, just get the bead through the slit.

Even if it's dark, but there's a lamp on the inside of the hallway, the slit would show up as a glowing cross within normal thrown weapon range.

[Talamare]

... You assume your wizard can't see something 60 feet away? Do they need corrective lenses?
In the DMG, Normal sight is 2 miles illuminated, 1 mile in the rain. Even racial darkvision is normally 60'.

What page is that on?

[LeonBH]

What page is that on?

DMG 243. Visibility Outdoors.

[GooeyChewie]

I assume that the Wizard sees the slit, not what is inside. It doesn't matter if they can't see what is inside the slit because of two reasons:

1. They can detonate the Fireball at the slit, and the explosion bends around corners
2. They can place the point of origin behind the slit, even if they can't see where they're putting it, due to the targeting rules

1. Great, you can have the fireball explode at the slit. I’ll allow that with no check, because you can easily find your line of effect to that point. And if you fail your free Perception check, that’s where it’ll go off, so there’s only a hinderance if you specifically want to cast through the slit.
2. Sure, you can set your point of origin behind the wall. But the fireball goes off if it hits an obstacle. So do you want me to let you make a free Perception check to get the spell past any obstacles which might be behind the arrow slit, or do you want to skip that part and automatically hit the archer instead of your target?


... You assume your wizard can't see something 60 feet away? Do they need corrective lenses?
In the DMG, Normal sight is 2 miles illuminated, 1 mile in the rain. Even racial darkvision is normally 60'.

Arrow Slits are traditionally in a cross or "t" formation, from 3-9 ft in height (and possibly length), width varies.
http://c8.alamy.com/comp/BYAEDP/arrow-slit-windows-in-a-wall-of-the-tower-of-london-BYAEDP.jpg

I just want you to realize that your argument is your wizard can't see a person-sized (or at least halfling-sized) literal x-marks-the-spot target at less than half the range of fireball (150 ft) and the goal isn't to hit a person you can see, just get the bead through the slit.

Even if it's dark, but there's a lamp on the inside of the hallway, the slit would show up as a glowing cross within normal thrown weapon range.
Did you look at that picture? Can you see inside those slits? Arrow slits are designed to be darkened; if they enemies have a lamp on in that hallway then they don’t understand how arrow slits work. (Which, hey, maybe you are fighting low INT monsters and they have bad tactics, but that’s not my default assumption.). And remember, the goal here isn’t just to hit the arrow slit, it’s to also NOT hit the person-sized person behind the slit (or if you aren’t currently being shot at, possibly closed shutters).

[LeonBH]

1. Great, you can have the fireball explode at the slit. I’ll allow that with no check, because you can easily find your line of effect to that point. And if you fail your free Perception check, that’s where it’ll go off, so there’s only a hinderance if you specifically want to cast through the slit.

Great. Take note the Fireball explodes in a 20ft radius, going around corners, so any archers standing behind it will get hit anyway.


2. Sure, you can set your point of origin behind the wall. But the fireball goes off if it hits an obstacle. So do you want me to let you make a free Perception check to get the spell past any obstacles which might be behind the arrow slit, or do you want to skip that part and automatically hit the archer instead of your target?

If I can make it explode at the slit without issue, why can't I extend it further down the line of effect and have it explode there?

Fireball automatically hits its targets because even on a successful Dex save, they take half damage. So it's not a question of if I want a perception check to hit, or automatically hit. Fireball automatically hits. It's a question of whether or not I can detonate a Fireball on the other side of the slit without a check.

And yes, I shouldn't need a check for that.

[GooeyChewie]

Great. Take note the Fireball explodes in a 20ft radius, going around corners, so any archers standing behind it will get hit anyway.
Which is great if your goal was solely to hit the archer and those closest to him, but we were presented with a scenario where the wizard specifically wants to have the fireball go off behind the archer.




If I can make it explode at the slit without issue, why can't I extend it further down the line of effect and have it explode there?
Because unless your opponents somehow left an arrow slit unattended and open, you have at a minimum a person in the way, and without taking a look you can’t be sure if your line of effect goes through that person. And I think it’s more fun to let the player try to aim the spell than to roll percentage to see if someone or something is in the way.


Fireball automatically hits its targets because even on a successful Dex save, they take half damage. So it's not a question of if I want a perception check to hit, or automatically hit. Fireball automatically hits. It's a question of whether or not I can detonate a Fireball on the other side of the slit without a check.
I’m not saying a failed Perception check would make the spell fizzle. I’m saying that if you cast a line of effect spell into an obscured area that contains an obstacle without checking, you’re most likely going to hit that obstacle. If I as the DM know that there’s nothing behind the arrow slit, the DC may be 0. If I know there are closed shutters, the DC may be irrelevant. If there’s an archer or other stuff, it’ll be somewhere in between.

Edit: By the way, the archer in that specific arrow slit? Yeah, he’s taking damage. The question is how much more of the interior will the fireball encompass.

[georgie_leech]

Yes. Same for Fighters.

But a scorching ray or other laser spell still needs an attack roll? That a +5 cover bonus to AC would apply to?

[Tanarii]

Fine then. A laser scope; turn it on, and have it go right through the arrow slit 60 feet away without touching the wall at all. Again, is that something the Wizard can do automatically? For the sake of their being mechanical consequences, say there's a bet where the prize is 100 gold. Do Wizards just get 100 gold in this scenario? Or would there be some sort of check involved? What if they were a Fighter instead?I know I've been coming down on the side of 'the DM can call for checks whenever there's a question of resolution', but the question you're asking seems to assume the PC can't just direct it visually & mentally. As in, if you can see it, you can automatically hit it.

Now in this case, most of us are assuming the PC can't see beyond the arrow slot. But the PC can see the slot itself. They should be able to at least get it to any open par of the slot they can clearly see. Which is why I wouldn't bother with a check, unless something particularly unusual going on: a very deep slot and they might be looking at a point that doesn't actual go through, far enough away they can't clearly distinguish the slot, etc.

This still doesn't mean a PC necessarily can do something like place a center point for the explosion exactly 19.5ft from an enemy and 20.5ft from an ally in melee with said enemy. Or place it exactly 112.5 ft from themselves (ie they don't know where 112.5ft from them self is, even though they can see clearly). It still doesn't answer how a caster determines explosion points when they can't see the target. But it certainly would explain precision of putting it where they want it when they can see the target point.

Basically it'd be the equivalent of having a laser pointer in your eyeballs, going exactly where you're looking. No margin for error. To base it on your analogy. Not saying this is how it works, just covering the alternatives to the analogy.


DMG states that if the person is behind total cover but somehow its still possible then it's 3 quarters. Pg251Thanks, appreciate it.

[LeonBH]

I’m not saying a failed Perception check would make the spell fizzle. I’m saying that if you cast a line of effect spell into an obscured area that contains an obstacle without checking, you’re most likely going to hit that obstacle. If I as the DM know that there’s nothing behind the arrow slit, the DC may be 0. If I know there are closed shutters, the DC may be irrelevant. If there’s an archer or other stuff, it’ll be somewhere in between.

Edit: By the way, the archer in that specific arrow slit? Yeah, he’s taking damage. The question is how much more of the interior will the fireball encompass.

Sure. I can agree with a Perception check to see the slit or what's behind it. What I'm opposed to is a Perception check to hit with the Fireball in the first place.



But a scorching ray or other laser spell still needs an attack roll? That a +5 cover bonus to AC would apply to?

Yes, "laser spells" require attack rolls and can miss. Three quarters cover applies.

[Asmotherion]

Why make it a check with a DC? It's not how Fireball work, and doing it is contrary to the principle of the spell. If you want to make spell like Fire Bolt harder to hit due to cover, fine, but Fireball explicitly avoid that.

If you want to rule it like this, well, it's your right as a DM, but I don't understand the reasoning.

Again, even if the Fireball explode in the slit, the explosion will go through.

At best, you could ask for a Wis(Perception) check to see if the PC can see through the slit.


As Unoriginal said. Shooting inside the slit only requires line of sight, if the fireball were to explode on the external wall, it will still affect the insides since it "spreads around corners" and the slit is a corner within the AoE.

Arrow slits were not designed to prevent fireball attacks in the middle age, they probably would have used other methods if that kind of magic was a thing back then.


All of this depend from DM to DM, Campain to Campain and how High or Low magic the Game is.

In a low magic World, a caster able to cast Fireball would be an exception to the rule, for example, with casters not being predicted in battle conditions. In a High Magic World on the other hand, what you say is probably true.

Now, the OP asked "How would you DM it?", and everyone went with their replys to it. Some, including myself support spell attack. It is not the RAW/RAI answear, it is the reply to how I would DM it, as I judge it would make things more realistic and intence, as well as rewarding in case it worked. Sometimes I feel that a DM should ignore RAW and go with whatever makes more sence and gives a better story, especially if you focus on the role playing aspect of the game.

On the other hand, if said mage was on his last 3rd level spell (last spell slot avalable to cast fireball), and after this was going to rely on cantrips for the rest of the day, I would allow an automatic success, as it is his moment to "shine".

[BeefGood]

As Unoriginal said. Shooting inside the slit only requires line of sight, if the fireball were to explode on the external wall, it will still affect the insides since it "spreads around corners" and the slit is a corner within the AoE.

Arrow slits were not designed to prevent fireball attacks in the middle age, they probably would have used other methods if that kind of magic was a thing back then.

Which raises a really interesting question: how would you design an arrow slit to defend against fireball attacks? Because the "spreads around corners" thing is weirder than I first appreciated. It seems like if there's any opening in the wall where the fireball contacts the wall, you end up with a partial sphere of fireball inside the structure. (I'm considering the fireball detonating just outside the structure.) It doesn't even have to be a straight hole, it could be a twisty mouse hole.
Arrow-slit-closets would work. The arrow slit is contained in a closet. One or two archers go into the closet and close the door. If a fireball detonates just outside the arrow slit, they are toast, but the fireball does not spread beyond the closet into the main part of the structure.
More archers wait outside the closet. On their turn, they open the door, pull out the unfortunate previous archers, get into the closet and close the door....repeat.

[Talamare]

So there seems to be 3 Stances

Stance A - The move is essentially Illegal, the Fireball explodes at the outside of the Arrow Slit

Stance B - The move is completely Legal, the Fireball may be cast into the Arrow Slit. Regardless of the accuracy, distance, size of the Arrow Slit.

Stance C - The move is Legal, but difficult. Give me a chance of success to get it into the Arrow Slit; otherwise it explodes outside the Arrow Slit.

[Vogie]

1. Great, you can have the fireball explode at the slit. I’ll allow that with no check, because you can easily find your line of effect to that point. And if you fail your free Perception check, that’s where it’ll go off, so there’s only a hinderance if you specifically want to cast through the slit.
2. Sure, you can set your point of origin behind the wall. But the fireball goes off if it hits an obstacle. So do you want me to let you make a free Perception check to get the spell past any obstacles which might be behind the arrow slit, or do you want to skip that part and automatically hit the archer instead of your target?

Did you look at that picture? Can you see inside those slits? Arrow slits are designed to be darkened; if they enemies have a lamp on in that hallway then they don’t understand how arrow slits work. (Which, hey, maybe you are fighting low INT monsters and they have bad tactics, but that’s not my default assumption.). And remember, the goal here isn’t just to hit the arrow slit, it’s to also NOT hit the person-sized person behind the slit (or if you aren’t currently being shot at, possibly closed shutters).

Yes, I can. It's dark (although, to be fair that specific picture is high enough resolution that I can see the mesh covering it to keep birds out... I presume the protective mesh is not included when archers are actively using the slit). I may not be able to see a person, but that's not what the OP was asking. It's a giant black X-shaped target during the day (or at night, with darkvision).

Also, AFAIK, we weren't told where precisely the wizard was when they cast Fireball in the OP. I assume that they're in a castle, above the horizon, and the fireball-bead would be cast in an upwards diagonal. If the bead hits a person, their helmet, an unlit torch, the roof, or even a well-placed black curtain, it'll fireball in a 20' area.

Although, if one wanted to fireball-proof their arrow slits, they could technically make all arrow slits in rooms with 40' ceilings. That would mean that, as long as the arrow slit is at least several stories up, and the wizard is a fixed distance away, the fireball would hit the ceiling and explode while the archers are safe.

Provided the Wizard doesn't know trigonometry, and can solve for C. Then they'll be able to figure out which point they can make the bead explode once it's inside the arrow slit. Because Math is a superpower.

Does anyone know if the OP's wizard is named Pythagoras?


Another option would be that arrow slits are always 120' up and accompanied by a 120' moat, so any fireballs shot from the ground would detonate at least 20' away from the arrow slit. Of course, the one shooting the fireballs is a wizard, who can either ignore the moat, fly upwards, or both, so that point is fairly moot.

[Tanarii]

I'm curious, how many DMs and players have a Fireball explode at the first creature along a straight line between a chosen point on a battle mat and the caster? Or do you just ignore creatures when determining a line of effect?

[E’Tallitnics]

Please read...

The Weave of Magic
The worlds within the D&D multiverse are magical places. All existence is suffused with magical power, and potential energy lies untapped in every rock, stream, and living creature, and even in the air itself. Raw magic is the stuff of creation, the mute and mindless will of existence, permeating every bit of matter and present in every manifestation of energy throughout the multiverse.

Mortals can’t directly shape this raw magic. Instead, they make use of a fabric of magic, a kind of interface between the will of a spellcaster and the stuff of raw magic. The spellcasters of the Forgotten Realms call it the Weave and recognize its essence as the goddess Mystra, but casters have varied ways of naming and visualizing this interface. By any name, without the Weave, raw magic is locked away and inaccessible; the most powerful archmage can’t light a candle with magic in an area where the Weave has been torn. But surrounded by the Weave, a spellcaster can shape lightning to blast foes, transport hundreds of miles in the blink of an eye, or even reverse death itself.

All magic depends on the Weave, though different kinds of magic access it in a variety of ways. The spells of wizards, warlocks, sorcerers, and bards are commonly called arcane magic. These spells rely on an understanding—Iearned or intuitive—of the workings of the Weave. The caster plucks directly at the strands of the Weave to create the desired effect. Eldritch knights and arcane tricksters also use arcane magic. The spells of clerics, druids, paladins, and rangers are called divine magic. These spellcasters’ access to the Weave is mediated by divine power-gods, the divine forces of nature, or the sacred weight of a paladin’s oath.

Whenever a magic effect is created, the threads of the Weave intertwine, twist, and fold to make the effect possible. When characters use divination spells such as detect magic or identify, they glimpse the Weave. A spell such as dispel magic smooths the Weave. Spells such as antimagic field rearrange the Weave so that magic flows around, rather than through, the area affected by the spell. And in places where the Weave is damaged or torn, magic works in unpredictable ways—or not at all.

So when a Wizard casts fireball at the arrow slit they're using The Weave to define a point in space (in the air itself) as the origin of its eventual detonation. The rules for spellcasting don’t say this but spells that travel from the caster to a target travel in a straight line.

As long as the Wizard has a clear path to the arrow slit then can certainly use The Weave to place the point of origin past that threshold along the same path, even if they cannot see what lies beyond.

If there is an obstruction the fireball detonates early when it impacts that obstruction. If not then the fireball travels to its point of origin and detonates as intended.

So to the OP you don’t need anything else unless you specifically want to make the game more difficult for the player's Wizard casting fireball​.

[Cybren]

That's a particular interpretation of how magic works, but not the only and obvious one and doesn't actually address the reasons people might give the scenario a failure chance.

[Arkhios]

I'd probably just give +5 to the reflex saves, and stick with the rules. If I somehow end up GMing D&D it's because my players wanted to do it, and this seems to be the way 5e favors handling it.

Now that you said it, I believe I would use that as well. Good call.

[E’Tallitnics]

That's a particular interpretation of how magic works, but not the only and obvious one and doesn't actually address the reasons people might give the scenario a failure chance.

That’s RAW for default D&D, which is how most questions are resolved unless the poster specifically mentions homebrew rules. Which wasn’t done.

So unless you wish to continue arguing for arguments sake the OPs question has been answered in full.

[Tanarii]

That’s RAW for default D&D, which is how most questions are resolved unless the poster specifically mentions homebrew rules. Which wasn’t done.

So unless you wish to continue arguing for arguments sake the OPs question has been answered in full.
"It's because The Weave" doesn't actually follow from the quote you provided with the text of what The Weave is. There's no logical connection between the two.

[Cybren]

"It's because The Weave" doesn't actually follow from the quote you provided with the text of what The Weave is. There's no logical connection between the two.

Right, exactly. Strictly applying the rules as written isn't wrong. But visualization of what those rules are trying to depict within the fiction isn't going to be universal.


That’s RAW for default D&D, which is how most questions are resolved unless the poster specifically mentions homebrew rules. Which wasn’t done.

So unless you wish to continue arguing for arguments sake the OPs question has been answered in full.
that's kind of a loose definition of 'homebrew'.

[E’Tallitnics]

"It's because The Weave" doesn't actually follow from the quote you provided with the text of what The Weave is. There's no logical connection between the two.

I’m sorry, but I can’t follow your sentence. Can you please elaborate on what you mean? Thank you!

[Beelzebubba]

I'd probably just give +5 to the reflex saves, and stick with the rules. If I somehow end up GMing D&D it's because my players wanted to do it, and this seems to be the way 5e favors handling it.


Bravo. This is the answer I was looking for.