Tell me about concealment and spells

[Festivus]

I understand how concealment works with melee and touch spells... some miss chance in the offing. I also understand that area of effect spells (a la fireball) don't care about concealment. But what about targetted spells?

If you cannot see the target I am assuming you cannot cast against it. What about if you use spot to locate, can you cast then? What about partial concealment versus total concealment? Then there are those wacky things like concealing amorpha psionic power, that has some special rules applied to it in terms of concealment and spells.

Can anyone point me to definitive information on this? It all seems... well, concealed from my understanding at the moment (or I have just not ingested sufficient levels of caffeine yet).

My initial take on it is that if you have total concealment of any kind, targetted spells cannot be cast against you.

 

[irdeggman]

From the SRD:

Ray: Some effects are rays. You aim a ray as if using a ranged weapon, though typically you make a ranged touch attack rather than a normal ranged attack. As with a ranged weapon, you can fire into the dark or at an invisible creature and hope you hit something. You don’t have to see the creature you’re trying to hit, as you do with a targeted spell. Intervening creatures and obstacles, however, can block your line of sight or provide cover for the creature you’re aiming at.

Line of Effect: A line of effect is a straight, unblocked path that indicates what a spell can affect. A line of effect is canceled by a solid barrier. It’s like line of sight for ranged weapons, except that it’s not blocked by fog, darkness, and other factors that limit normal sight.

You must have a clear line of effect to any target that you cast a spell on or to any space in which you wish to create an effect. You must have a clear line of effect to the point of origin of any spell you cast.

A burst, cone, cylinder, or emanation spell affects only an area, creatures, or objects to which it has line of effect from its origin (a spherical burst’s center point, a cone-shaped burst’s starting point, a cylinder’s circle, or an emanation’s point of origin).

Total Concealment: If you have line of effect to a target but not line of sight he is considered to have total concealment from you. You can’t attack an opponent that has total concealment, though you can attack into a square that you think he occupies. A successful attack into a square occupied by an enemy with total concealment has a 50% miss chance (instead of the normal 20% miss chance for an opponent with concealment).
You can’t execute an attack of opportunity against an opponent with total concealment, even if you know what square or squares the opponent occupies.

 

[Festivus]

Hmm, that isn't quite answering the question I asked. After some discussion on my boards, we came up with a table:

[center][b]Table of Visibility[/center][/b]

	            Melee/Ranged Attack?	Miss Chance	Targetted Spells	AoE / Line Effects
Invisible			No		100%		No			Yes
Invisible (spotted)(1)		Yes		50%		No			Yes
Displacement			Yes		50%		Yes			Yes
Blinking			Yes		50%		Yes (2)			Yes(3)
Partial Concealment		Yes		20%		Yes			Yes
Total Conceament		Yes		50%		No			Yes

(1) - Invisible creatures must be successfully respotted each round in order to attack them.
(2) - A targetted spell against a blinking creature has a 50% chance of failure.
(3) - A area of effect only does 50% of damage to a blinking creature.

The question was more to do with could a creature who is concealed... but spotted be targetted by spells. My inclination was that they cannot be. I wasn't asking about melee / ranged weapon attacks at all.

 

[irdeggman]

The question was more to do with could a creature who is concealed... but spotted be targetted by spells. My inclination was that they cannot be. I wasn't asking about melee / ranged weapon attacks at all.

Actually it does.

It specifically talks about rays (which arre the spells your actually talkinga bout) - it then says that

As with a ranged weapon, you can fire into the dark or at an invisible creature and hope you hit something.

 

[Festivus]

So what about something like Maze, where the target is One Creature. That was my intent, sorry if I was confusing things.

 

[starwed]

Your initial terminology was correct. A ray is not considered a "targeted spell." Total concealment definately prevents line of sight, and thus targeted spells in most cases. Although if you can physically touch an invisible creature, that'll let you target them. (Useful for allies.)

 

[Ogrork the Mighty]

I wish WotC would come up with some simple rules for what a character can and cannot see in the heat of battle, especially when it comes to targetting that guy on the other side of the cavern with 14 different combatants in front of him!

 

[shilsen]

I wish WotC would come up with some simple rules for what a character can and cannot see in the heat of battle, especially when it comes to targetting that guy on the other side of the cavern with 14 different combatants in front of him!

They already have. If there are no extenuating circumstances covered under cover and concealment, you can see anyone on the battlefield.

And if a DM finds that unrealistic, he can house rule it. Simple.

 

[irdeggman]

Line of sight is what is in question here.

PHB: Glossary (pg 310)

line of sight: Two creatures can see each other if they have line of sight to each other. To determine line of sight, draw an imaginary line between your space and the target’s space. If any such line is clear (not blocked), then you have line of sight to the creature (and it has line of sight to you). The line is clear if it doesn’t intersect or even touch squares that block line of sight. If you can’t see the target (for instance, if you’re blind or the target is invisible), you can’t have line of sight to it even if you could draw an unblocked line between your space and the target’s.

SRD

Blinded: The character cannot see. He takes a –2 penalty to Armor Class, loses his Dexterity bonus to AC (if any), moves at half speed, and takes a –4 penalty on Search checks and on most Strength- and Dexterity-based skill checks. All checks and activities that rely on vision (such as reading and Spot checks) automatically fail. All opponents are considered to have total concealment (50% miss chance) to the blinded character. Characters who remain blinded for a long time grow accustomed to these drawbacks and can overcome some of them.

Total Concealment does not equal not being able to be seen.

Not being able to be seen does equal total concealment though. {See earlier quote on concealment}


So basically it is up to the DM whether or not someone can be seen. Two cases that are called out though are invisible target and blind attacker.

 

[Festivus]

In the spirit of moving forward, I wrote a quickie cheat sheet PDF. Anyone who cares to review and provide feedback if I got something wrong or if there are effects missing that should be on the table, let me know and I will update it.

Visibility Table