I don’t understand when you need line of sight and line of effect with spells

[Myth27]

First of all, am I correct to assume that there is a general rule that requires you to have both for spells?
Second if the spells says “you can target any [thing with specific characteristics] within range.” Is the spell saying you can ignore line of effect?
Third can you explain it in general? What spells do not require line of effect/sight ?

[DMThac0]

There's a lot of information to work with here:

Cover

Walls, trees, creatures, and other obstacles can provide cover during combat, making a target more difficult to harm. A target can benefit from cover only when an attack or other effect originates on the opposite side of the cover.
There are three degrees of cover. If a target is behind multiple sources of cover, only the most protective degree of cover applies; the degrees aren't added together. For example, if a target is behind a creature that gives half cover and a tree trunk that gives three-quarters cover, the target has three-quarters cover.
A target with half cover has a +2 bonus to AC and Dexterity saving throws. A target has half cover if an obstacle blocks at least half of its body. The obstacle might be a low wall, a large piece of furniture, a narrow tree trunk, or a creature, whether that creature is an enemy or a friend.
A target with three-quarters cover has a +5 bonus to AC and Dexterity saving throws. A target has three-quarters cover if about three-quarters of it is covered by an obstacle. The obstacle might be a portcullis, an arrow slit, or a thick tree trunk.
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.

If a spell requires line of sight to make an attack then it could hit anything not considered under total cover. Area of Effect (AoE) spells could hit a target under any of these circumstances.

Unseen Attackers and Targets

Combatants often try to escape their foes' notice by hiding, casting the invisibility spell, or lurking in darkness.

When you attack a target that you can't see, you have disadvantage on the attack roll. This is true whether you're guessing the target's location or you're targeting a creature you can hear but not see. If the target isn't in the location you targeted, you automatically miss, but the GM typically just says that the attack missed, not whether you guessed the target's location correctly.

When a creature can't see you, you have advantage on attack rolls against it. If you are hidden–both unseen and unheard–when you make an attack, you give away your location when the attack hits or misses.

Hide

When you take the Hide action, you make a Dexterity (Stealth) check in an attempt to hide, following the rules for hiding. If you succeed, you gain certain benefits, as described in the “Unseen Attackers and Targets” section.

Spells that require line of sight would suffer the same dis/advantage as a melee attack roll in this situation. AoE spells would not.

-----

As a general rule, when reading the spell's description, it will give phrases to work with to help figure out if you need to see your target:

"Make a ranged spell attack. On hit,": Would require line of sight, otherwise it is affected by the circumstances listed above.

"Each dart hits a creature you can see.": This descriptor does all the thinking for you.

"Each creature in a 20-foot radius Sphere centered on that point": Indicates that line of sight is not necessary.

"The fire spreads around corners.": Indicates that line of sight is not necessary.

----

I hope this is helpful, and I'm sure others will give more examples!

[PhoenixPhyre]

First: neither term is a defined game term in 5e.

Second: all spells (unless they say otherwise) need a clear path to the target (point or creature/object).

Third: the caster only needs to be able to see the target if the spell explicitly says so.

Trends:
* Attack roll spells (generally) don't require you to see your target. Because they follow the unseen attacker/unseen target rules (for hiding), granting advantage/disadvantage as appropriate.
* Area-targeted spells vary. Fireball, for example, does not require a clear view of the target. You can totally fireball the darkness.
* Creature-targeted save-based spells (and magic missile) generally do require sight. They'll say "choose a target you can see" or something similar.
* A very few also require the target to be able to hear or see the caster. Those ones call it out explicitly.

So basically, all spells require a clear path to the target (except those that say otherwise), like message or sending. But spells only require sight if they say they do.

[MaxWilson]

First of all, am I correct to assume that there is a general rule that requires you to have both for spells?
Second if the spells says “you can target any [thing with specific characteristics] within range.” Is the spell saying you can ignore line of effect?
Third can you explain it in general? What spells do not require line of effect/sight ?

Aren't these questions for your DM? If you're the DM and you don't see a good reason for the rule, write a different one.

IMO these rules exist primarily for ease of play on simplistic battlegrids. There's no deep magical theory behind it unless the DM invents it. Note that there are already implicit exceptions to the rules built into the game, e.g. Scrying and Clairvoyance obviously don't obey the rule about total cover blocking spells.

[Man_Over_Game]

One thing that adds some interesting complications is that Cover represents a physical obstruction, such as a wall, a pillar, or even a person. Obscuration is specific to sight, with things such as Fog Cloud and Invisibility.

This is important for things like Spiritual Weapon, where your sight and the source of the attack may very well be different. If there is a pillar between you and the bad guy, but nothing between the bad guy and the Spiritual Weapon, the attack is not hindered by Cover. However, if there is an illusion blocking you from seeing the target, but nothing between the Spiritual Weapon and the enemy, you would have disadvantage to attack that target with the Spiritual Weapon.

Most spells require a direct line of sight to cast, especially if they state that you choose a target.

Cover would provide AC for anything that use an attack roll, but does not impact saving throws.
Obscuration would provide a means to hide, or with Heavy Obscuration, a complete lack of vision.

Generally, Cover and Obscuration go hand-in-hand (like with a wall), since most of the time, your vision is blocked by an object, but sometimes that's not always true (Wall of Force is indestructible but see through, Fog Cloud is impossible to see through but it's not solid).

An Attack Roll can be made on pretty much anything, even on an empty space, but you get disadvantage to hit a target if you cannot see it, and the target gets bonuses if there are objects in the way (AKA Cover). A Saving Throw effect can usually only be used if you can see the target, but doesn't suffer any penalties from Cover.

[Keravath]

I think this is mostly covered in the PHB chapter on spellcasting: PHB204

TARGETS
A typical spell requires you to pick one or more targets to be affected by the spell's magic. A spell's description tells you whether the spell targets creatures, objects, or a point of origin for an area of effect (described below). Unless a spell has a perceptible effect, a creature might not know it was targeted by a spell at all. An effect like crackling lightning is obvious, but a more subtle effect, such as an attempt to read a creature's thoughts, typically goes unnoticed, unless a spell says otherwise.

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.

AREAS OF EFFECT
Spells such as burning hands and cone of cold cover an area, allowing them to affect multiple creatures at once. A spell's description specifies its area of effect,
which typically has one of five different shapes: cone, cube, cylinder, line, or sphere. Every area of effect has a point of origin, a location from which the spell's
energy erupts. The rules for each shape specify how you position its point of origin. Typically, a point of origin is a point in space, but some spells have an area whose origin is a creature or an object. A spell's effect expands in straight lines from the point of origin. If no unblocked straight line extends from the point of origin to a location within the area of effect, that location isn't included in the spell's area. To block one of these imaginary lines, an obstruction must provide total cover, as explained in chapter 9.


Unless the spell text says otherwise, the spell must have a clear path to the affected creatures from the point of origin of the spell. So if you cast a spell on a target within range it can not be behind total cover. If you cast an area of effect spell on a point within range then the creatures affected can't be behind total cover from the point of origin of the spell unless the spell text says otherwise (e.g. fireball expands around corners but shatter does not so a creature behind a wall or other total cover from the point of origin of a shatter spell would not be affected even if they are within the 10' radius area of effect).

Other spells can only be cast on something you can see as well as following the path to target rules.

Total cover applies when "A target has total cover if it is completely concealed by an obstacle." This means that a creature behind a window or other transparent substance would probably not have total cover because they are not "concealed" though it likely falls into the realm of a DM call if spells could pass through a wall of transparent aluminum :) ... or 5' thick glass ... or a sheet of smoothly falling water.



P.S. Scrying has a range of self ... so cover isn't relevant. Clairvoyance on the other hand has a range of a mile, however, the examples in the text are of places you can't see (and RAI I am sure that is what is intended).

[tieren]

I don't find much textual support for the line of effect beliefs many seem to share, most spells say nothing about it.

For purposes of line of effect discussions I picture a wizard in a glass cell, sealed on every side such that vision is not impaired but line of effect is. What spells can the wizard cast on targets outside the box? (not including things that would just break the glass to get line of effect)

Hold Person? it just mentions a humanoid you can see within range, as long as the targeting conditions are met (vision, valid target, range) you should be able to cast it regardless of line of effect.

How about heroes Feast? It just says "you bring forth a great feast", it doesn't saying anything about vision, or a space you can see, or food flies from your fingers to the location chosen, only a range (30 feet). Can you bring it forth outside the glass box? Can you bring it forth inside the next room affected by magical darkness behind a total cover stone wall?

[PhoenixPhyre]

I don't find much textual support for the line of effect beliefs many seem to share, most spells say nothing about it.

For purposes of line of effect discussions I picture a wizard in a glass cell, sealed on every side such that vision is not impaired but line of effect is. What spells can the wizard cast on targets outside the box? (not including things that would just break the glass to get line of effect)

Hold Person? it just mentions a humanoid you can see within range, as long as the targeting conditions are met (vision, valid target, range) you should be able to cast it regardless of line of effect.

How about heroes Feast? It just says "you bring forth a great feast", it doesn't saying anything about vision, or a space you can see, or food flies from your fingers to the location chosen, only a range (30 feet). Can you bring it forth outside the glass box? Can you bring it forth inside the next room affected by magical darkness behind a total cover stone wall?

The line of effect rules are in the general spell-casting rules (as quoted above). Line of sight is spell-specific.

[jas61292]

Total cover applies when "A target has total cover if it is completely concealed by an obstacle." This means that a creature behind a window or other transparent substance would probably not have total cover because they are not "concealed" though it likely falls into the realm of a DM call if spells could pass through a wall of transparent aluminum :) ... or 5' thick glass ... or a sheet of smoothly falling water.

This is hugely important. Line of effect essentially is line if sight in this edition. It's easy to assume that they are completely independent things, but nothing in the rules really supports that. I mean, no, they are not exactly the same, but if you have line if sight, you have line of effect.

Whether or not some magic can actually work through certain kinds of transparent objects in clear DM discretion territory, but the rules do seem to allow targeting such things.

[PhoenixPhyre]

This is hugely important. Line of effect essentially is line if sight in this edition. It's easy to assume that they are completely independent things, but nothing in the rules really supports that. I mean, no, they are not exactly the same, but if you have line if sight, you have line of effect.

Whether or not some magic can actually work through certain kinds of transparent objects in clear DM discretion territory, but the rules do seem to allow targeting such things.

To muddy the waters a bit, there are JC tweets to the effect that Wall of Force (or any physical obstruction) blocks line of effect even if transparent. Which makes a certain sense. You can't cast fireball at a point behind an invisible stone wall--there's a wall in the way.

Note that there's also a line to the effect that "for area targeted spells with a hidden obstruction, the area of effect comes into existence on the caster's side of the barrier".

[DMThac0]

This is hugely important. Line of effect essentially is line if sight in this edition. It's easy to assume that they are separate things, but nothing in the rules really supports that. I mean, no, they are not exactly the same, but if you have line if sight, you have line of effect.

Whether or not some magic can actually work through certain kinds of transparent objects in clear DM discretion territory, but the rules do seem to allow targeting such things.

I would beg to differ in a situational context:

Burning Hands creates a conical spread of flames, it's line of effect being that 15ft cone.
Gust of wind make a line of wind as it's line of effect.

Ray of Frost shoots a beam out at the target, but doesn't affect anything in that 60ft distance except the intended target, which requires line of sight.
Power Word Pain, it has a range of 60ft, nothing between the target and the caster is affected, line of sight is needed.

---

It's not a perfect argument, but it could be used to create some clarification on certain contextual situations.

[EvilAnagram]

I tend to interpret the line of effect text primarily in its effect on AoEs. A fireball won't travel through stone walls, for example.

[PhoenixPhyre]

Ray of Frost shoots a beam out at the target, but doesn't affect anything in that 60ft distance except the intended target, which requires line of sight.


Ray of frost does not need line of sight at all. You can shoot it at an invisible target as long as you know in some other way they're there.

Line of sight and line of effect are completely separate here. You can have

* LoS but not LoE: target is behind an invisible wall (like a Wall of Force).
* LoE but not LoS: an invisible target in the open.
* both: the normal case
* neither: total obscurement and total cover

LoE: can a physical projectile travel in a straight line from the caster to the target without running into anything solid?
LoS: is the target visible to the caster?

They're orthogonal conditions. LoE defaults to required (with exceptions), LoS defaults to not required (with exceptions).

[Tanarii]

My simple guideline is:
- spells need a clear path from the caster to a target (or to the target origin point for AoEs) unless they say otherwise.
- AoE spells need a clear path from the origin point to the target affected by it, unless they say otherwise.
- spells do not need the ability to see the target, unless they say otherwise

[Myth27]

What is a clear path from the caster to the target? Is it a straight line?

[PhoenixPhyre]

What is a clear path from the caster to the target? Is it a straight line?

Yes. A straight, unobstructed line.

If you're using a grid, it's defined as if a line can be drawn from any corner of the caster's space to any corner of the target's space without obstruction. If none of the lines pass through an obstruction, there is no cover. If 1 (or 2?) do, then it's half-cover (+2 AC/Dex saves). If 3 do, it's 3/4 cover (+5). If all are obstructed, then total cover.

[E’Tallitnics]

[…]

Cover would provide AC for anything that use an attack roll, but does not impact saving throws.

[…]


Actually cover does impact Dexterity saving throws:



A target with half cover has a +2 bonus to AC and Dexterity saving throws. A target has half cover if an obstacle blocks at least half of its body. The obstacle might be a low wall, a large piece of furniture, a narrow tree trunk, or a creature, whether that creature is an enemy or a friend.

A target with three-quarters cover has a +5 bonus to AC and Dexterity saving throws. A target has three-quarters cover if about three-quarters of it is covered by an obstacle. The obstacle might be a portcullis, an arrow slit, or a thick tree trunk.

[tieren]

My simple guideline is:
- spells need a clear path from the caster to a target (or to the target origin point for AoEs) unless they say otherwise.
- AoE spells need a clear path from the origin point to the target affected by it, unless they say otherwise.
- spells do not need the ability to see the target, unless they say otherwise

I would agree if "clear path" in the first bullet meant clear as in can see through, and in the second bullet clear as in unobstructed by a physical object.

Heres one for you, Call Lightning - you have to see the point where the cloud forms, and you have to see the point you want the bolt to hit, but it doesn't say what happens if the point you want the bolt to hit has total cover from above (maybe they are inside a steel quansit hut with an open end towards the caster). Would the bolt find its way to the point the caster picked even if it couldn't hit it striking straight down from the cloud?

[Tanarii]

I would agree if "clear path" in the first bullet meant clear as in can see through, and in the second bullet clear as in unobstructed by a physical object.But that would be wrong. You need an unobstructed path to either the target of the spell, or the origin of the AoE. So the first bullet point is (typically) correct. Neither of them have anything to do with seeing, both have to do with no physical obstruction.


Heres one for you, Call Lightning - you have to see the point where the cloud forms, and you have to see the point you want the bolt to hit, but it doesn't say what happens if the point you want the bolt to hit has total cover from above (maybe they are inside a steel quansit hut with an open end towards the caster). Would the bolt find its way to the point the caster picked even if it couldn't hit it striking straight down from the cloud?DMs ruling. It says the bolt comes from the cloud per the specifics of the spell. So IMO a DM should rule it as "unless a spell says otherwise" for my first guideline. That's just my ruling though.

[E’Tallitnics]

I would agree if "clear path" in the first bullet meant clear as in can see through, and in the second bullet clear as in unobstructed by a physical object.

Heres one for you, Call Lightning - you have to see the point where the cloud forms, and you have to see the point you want the bolt to hit, but it doesn't say what happens if the point you want the bolt to hit has total cover from above (maybe they are inside a steel quansit hut with an open end towards the caster). Would the bolt find its way to the point the caster picked even if it couldn't hit it striking straight down from the cloud?

The bold of lightning would impact the cover, per the rules on AoE: Cylinder


Cylinder

A cylinder's point of origin is the center of a circle of a particular radius, as given in the spell description. The circle must either be on the ground or at the height of the spell effect. The energy in a cylinder expands in straight lines from the point of origin to the perimeter of the circle, forming the base of the cylinder. The spell's effect then shoots up from the base or down from the top, to a distance equal to the height of the cylinder.

A cylinder's point of origin is included in the cylinder's area of effect.

[Tanarii]

The bold of lightning would impact the cover, per the rules on AoE: Cylinder
Why? It's not an AoE.

Actually rereading the spell, I believe I've been doing it wrong. With good reason, but still. It probably should be a clear path to "each creature within 5ft of that point". So cover between the point the lightning bolt strikes and the creature should protect.

But I like cover from above more, because that's the way a quick glance reading is going to judge it.

Regardless, this spell is a pretty good example of "unless the spell says otherwise" as far as I'm concerned. Edit: and exactly why I said simple guidelines, as opposed to simple hard rules.

[EvilAnagram]

Why? It's not an AoE.
...yes it is.

On top of being a 10'×60' cylinder, the lightning impacts in a 5' radius.

[Tanarii]

...yes it is.

On top of being a 10'×60' cylinder, the lightning impacts in a 5' radius.
Granted on the latter part, that's why I'm fairly sure I've been Doing it Wrong(tm). But the spell makes it pretty clear the "cylinder" isn't part the AoE-like effect of the spell. The damage doesn't occur within it. That's what I was referring to.

[EvilAnagram]

Granted on the latter part, that's why I'm fairly sure I've been Doing it Wrong(tm). But the spell makes it pretty clear the "cylinder" isn't part the AoE-like effect of the spell. The damage doesn't occur within it. That's what I was referring to.
Ah, I see what you're saying.

[tieren]

But that would be wrong. You need an unobstructed path to either the target of the spell, or the origin of the AoE. So the first bullet point is (typically) correct. Neither of them have anything to do with seeing, both have to do with no physical obstruction.


I disagree, there is nothing I can find in the rules that would prevent casting hold person at a valid target you can see through a sheet of glass.

[Tanarii]

I disagree, there is nothing I can find in the rules that would prevent casting hold person at a valid target you can see through a sheet of glass.
PHB 203:
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.

PHB 196:
Cover
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 sheet of glass provides (very poor) total cover. Unless it's super thick it's probably got all of 1 hp. But it is still total cover. It's an object between the target and the person targeting.

Edit: personally a house rule that total cover reduces any attack that destroys it by that amount sounds reasonable. But I've not yet had someone try to shoot a crossbow bolt or fireball at someone behind a sheet of glass. In the latter case, it would cause the fireball or other AoE origin to be just outside the glass (with or without this house rule). But it would stop 100% of a non-damaging spell like Hold Person, even with that house rule.

[tieren]

PHB 203:
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.

PHB 196:
Cover
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.



Those two definitions are circular, it can't be targeted if it's behind total cover and it's behind total cover if it can't be targeted. They don't help us determine what can be targeted.

The fireball is a clear case it detonate on the near side of the window, I want to focus on one's that are less clear, like hold person.

What if instead of glass the screen was a sheet of cascading water or a thin sheet of (clear) ice?

Or how about hypnotic pattern or prismatic spray? Would someone in the area of effect, but behind clear glass looking at the effect be affected?

[Tanarii]

Those two definitions are circular, it can't be targeted if it's behind total cover and it's behind total cover if it can't be targeted. They don't help us determine what can be targeted.They are not circular. They are two different places stating the same rule. You cannot target something behind total cover.


The fireball is a clear case it detonate on the near side of the window, I want to focus on one's that are less clear, like hold person.Both are clear. If it's behind total cover, it cannot be targeted.


What if instead of glass the screen was a sheet of cascading water or a thin sheet of (clear) ice?I would not count the water as cover, but other DMs might. I'd definitely count ice as cover, same as glass.

I feel like the question you're really trying to ask is "does glass count as cover?" Because cover blocking any spell that doesn't say over wise, or use the AoE rules to get around it, is explicit in two different places, that I quoted. A separate (and valid) question is: what counts as cover.


Or how about hypnotic pattern or prismatic spray? Would someone in the area of effect, but behind clear glass looking at the effect be affected?If it counts as cover, it prevents the AoE from going from its origin past it.

So as long as you agree with a ruling that glass is a solid enough object that it provides cover, yes, it would prevent both provided you were on the other side from the origin of the cube and cone, respectively.

Edit to be clear, the area wouldn't even be in the AoE, it would be excluded from it. If a spell were to create something that affected creatures looking at even if outside the area, then it could affect a creature on the other sided of clear cover. But Hypnotic Pattern requires you to also be inside the affect cube, not just looking at the pattern from outside it.

[tieren]

I'm trying to draw a distinction between line of sight and line of effect.

And I believe you are right saying I am really asking if glass provides total cover. I posit that it does not because you can target creatures behind it.

Suppose the glass were so clear as to be invisible. If a player said they wanted to shoot a crossbow at a target on the other side would you tell them they find it impossible to target anything, or more reasonably would you let them aim at what they see and take the shot (then adjudicating whether the effect of the barrier).

Aiming and targeting are synonymous to me, and I would allow spells that don't require line of effect (like fireball or firebolts, etc) to be effectively used.

[Dalebert]

It makes magic far too powerful if you ignore the rule for a clear path to the target. Without it, there's nothing stopping you from using Clairvoyance and casting spells on someone in another room before they have any chance of fighting back. Meanwhile a spell like Wall of Force becomes far too weak. The whole point of it is protection, but this would mean spellcasters could largely ignore it and continue to target you with a variety of very powerful spells. A "wall" spell is meant to block things, WoF included, and the rule about a clear path to the target was meant to show that most magic isn't intended to be so powerful as to simply ignore solid barriers.


... I am really asking if glass provides total cover. I posit that it does not because you can target creatures behind it.

If you don't know there's a barrier there, then of course you can let someone target something. Otherwise you're providing them with meta info they shouldn't have. The spell just wouldn't work (generally). See more comments below.


If a player said they wanted to shoot a crossbow at a target on the other side would you tell them they find it impossible to target anything, or more reasonably would you let them aim at what they see and take the shot (then adjudicating whether the effect of the barrier).

Considering that a bullet definitely wouldn't be stopped by glass, I imagine a crossbow bolt could potentially hurt someone on the other side as well. Glass is fragile and it's reasonable to take that into consideration. There are lots of reasonable DM adjudications for such weird cases. You could roll dmg against the glass and apply leftover dmg if it hits, just as a for instance. A Wall of Force or most other solid barriers? Absolutely not. Full stop. Nope.


Aiming and targeting are synonymous to me, and I would allow spells that don't require line of effect (like fireball or firebolts, etc) to be effectively used.

Those are very odd examples because why would they be exceptions to the "clear path to the target" rule? You're saying fire should just ignore solid barriers? That said, I don't see why not to adjudicate a firebolt in a similar manner to a crossbow bolt above. Again, glass is pretty fragile. Maybe a strong enough firebolt destroys it and keeps going, depending on how the DM wants to adjudicate. A Hold Person spell on the other hand, is not going to destroy the glass. It can only affect a creature and it does no dmg so it's going to hit the (invisible?) glass, the glass barrier will remain, and the spell will just fizzle with no effect.

Per RAW anyway, but maybe a DM will want to adjudicate differently for glass based on it just being fairly weak. Taking it a little further, I would not let a wall of plastic wrap stop a Hold Person spell. And someone mentioned a thin sheet of falling water. I'd have to say no to that as a solid barrier. It's not solid by definition, and if we did let it, then almost no spells would work underwater which would make underwater adventures rather silly.

[Tanarii]

I'm trying to draw a distinction between line of sight and line of effect.

And I believe you are right saying I am really asking if glass provides total cover. I posit that it does not because you can target creatures behind it.That's back to front. Total cover denies the abilty to target. It is not defined by if you can target.


Suppose the glass were so clear as to be invisible. If a player said they wanted to shoot a crossbow at a target on the other side would you tell them they find it impossible to target anything, or more reasonably would you let them aim at what they see and take the shot (then adjudicating whether the effect of the barrier).I'd let them aim and loose a bolt. But they wouldnt be able to target the creature with an attack.


Aiming and targeting are synonymous to me,That explains why you're having issues with the RAW. Targeting is about making a mechanical attack (or spell, etc) that has a chance to have a game effect. Not aiming.

[PhoenixPhyre]

Firebolt absolutely requires a clear path to target. It no-where says otherwise. Fireball (and all other point-targeted aoes) have explicit rules about what happens with an seen obstruction in the line of fire.

* Attack spells--cannot hit the target, but may damage the cover at DM's discretion.
* Save spells--can't latch on. If you didn't know about the obstruction, the spell simply fails as if the target made their save.
* AoE spells--the barrier serves as the new target location and they may spread around corners if stated.
** Fireball spreads explicitly. Shatter does not, so there needs to be a clear path between the actual center of the effect and the target for it to have an effect.

In the case of a glass barrier, I'd have shatter or fireball break the obstruction and (if dramatically appropriate) have the target count as having made their save (so half-damage). Firebolt or similar would simply splash on the glass/break the glass but dissipate without damaging the target. Hold person would simply fail with no information given.

[ThePolarBear]

Aiming and targeting are synonymous to me

They aren't. Targeting is simply the process of making a choice.

[PhoenixPhyre]

They aren't. Targeting is simply the process of making a choice.

And not all effects even need aiming. Magic Missile is a prime example--given a (valid) target, it hits. Full stop.

I tend to treat attack spells (and weapon attacks) as needing aiming of a projectile or beam. Save spells don't necessarily create a projectile that crosses the intervening space (some do, some don't), but the magic needs a clear path to travel regardless in order to take effect. But those save spells are targeting the soul (or the location) and so can't be dodged/blocked by armor or a shield, etc.

[Keravath]

I would agree if "clear path" in the first bullet meant clear as in can see through, and in the second bullet clear as in unobstructed by a physical object.

Heres one for you, Call Lightning - you have to see the point where the cloud forms, and you have to see the point you want the bolt to hit, but it doesn't say what happens if the point you want the bolt to hit has total cover from above (maybe they are inside a steel quansit hut with an open end towards the caster). Would the bolt find its way to the point the caster picked even if it couldn't hit it striking straight down from the cloud?

I think that is covered by:

"A spell's effect expands in straight lines from the point of origin. If no unblocked straight line extends from the point of origin to a location within the area of effect, that location isn't included in the spell's area."

Calling Lightning on a target that you can see but which has total cover from the point of origin of the lightning could not be affected by the lightning.

[Tanarii]

I think that is covered by:

"A spell's effect expands in straight lines from the point of origin. If no unblocked straight line extends from the point of origin to a location within the area of effect, that location isn't included in the spell's area."

Calling Lightning on a target that you can see but which has total cover from the point of origin of the lightning could not be affected by the lightning.
But apparently the point of origin is apparently the strike point. Thestraight lines extend from there to the target creatures within 5ft of it.

Although you also need a clear path from yourself to the point of origin of of an Aoe. So from the caster (not the cloud) to the point within 120ft range

Call Lightning is definitely one of the least clear. Unlike hold person though a glass pane, which is crystal clear.

[ThePolarBear]

But apparently the point of origin is apparently the strike point. Thestraight lines extend from there to the target creatures within 5ft of it.

Although you also need a clear path from yourself to the point of origin of of an Aoe. So from the caster (not the cloud) to the point within 120ft range

Call Lightning is definitely one of the least clear. Unlike hold person though a glass pane, which is crystal clear.

The point of origin of the AoE is clear, however the lightning that strikes is the origin of the effect, and the origin of the lightning is the cloud. To be able to target the point, you need to see it. To be able to have an effect on the point, the lightning needs to be able to reach it. If there is a way for the lightning to reach the point from the cloud, then the line is formed. Otherwise you have this:

"lf 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."

This happens when you have an obtruction to a point that you can't see. I would posit that it's also a reasonable conclusion on what happens when you see a point but not see the obstruction. Obviously, this is not RAW but RAI (IMHO), as it would play out differently by going purely RAW - the lighting would strike and the effect would be there, even with an obstruction, since there is no obstruction between you and the chosen point, or the opposite in the opposite situation.

[Tanarii]

This happens when you have an obtruction to a point that you can't see. I would posit that it's also a reasonable conclusion on what happens when you see a point but not see the obstruction. Obviously, this is not RAW but RAI (IMHO), as it would play out differently by going purely RAW - the lighting would strike and the effect would be there, even with an obstruction, since there is no obstruction between you and the chosen point, or the opposite in the opposite situation.
I agree the rule should be an obstruction between the cloud and the origin point prevents the Lightning. Just as one between the strike point and a target would prevent, or provide a bonus to the Dex save if less than complete.

But I think as written, if there is no clear path between the caster and the strike point, then the lightning strike from the cloud is blocked. Because that's the default rule and the spell doesn't clearly call it out as an exception. Unlike Sacred Flame, which explicitly says the target gains no benefit from, for a reason. Otoh it does explicitly describe how the strike occurs, and that could be considered an exception. It's just not an explicit exception.

[ThePolarBear]

But I think as written, if there is no clear path between the caster and the strike point, then the lightning strike from the cloud is blocked. Because that's the default rule and the spell doesn't clearly call it out as an exception. Unlike Sacred Flame, which explicitly says the target gains no benefit from, for a reason. Otoh it does explicitly describe how the strike occurs, and that could be considered an exception. It's just not an explicit exception.

Yes, i agree. It was what i was trying to say, in a very convoluted and incomprehensible way :D