Burst Effects vs Barriers

[Kaouse]

Suppose Wizard A casts Wall of Stone, and hides behind it. After taking some damage, the Wall of Stone is left at 1 hp.

Wizard B then casts Fireball, trying to attack Wizard B.

Does the Fireball hurt Wizard A?

On one hand, Fireball has no line of effect to Wizard A at the time of it's casting. On the other hand, the damage dealt from the Fireball exceeds the hp of the barrier, meaning that the Fireball should destroy the barrier. If the barrier is destroyed, would Wizard A then be in the burst effect radius, taking full damage?

Now what happens if Wizard A is hiding behind a full strength Wall of Force, but Wizard B casts "Mage's Disjunction" which explicitly destroys Walls of Force?

Is Wizard A (and his items) subject to the Disjunction? Or does he not count as a target due to Wall of Force blocking Line of Effect?

Feel free to replace Wall of Force with Prismatic Sphere if you feel that "level difference" plays a role important.

[Claxon]

I believe the answer is no to all of your question.

But if you cast the spells a second time, then it would affect them. This is because the spells are instantaneous and at the time of creation of the effects, they are blocked by the respective barriers. The barriers are destroyed by the spell, but the spell doesn't persist long enough to do anything else.

[Kaouse]

Mage's Disjunction has a duration, actually. It doesn't say it's instantaneous.

[Claxon]

So it does, I remembered incorrectly.

So that would work after breaking through the wall of force, although it would be stopped by a regular wall.

[EvilMinion]

If the fireball does enough damage to destroy a barrier (like a door, or your afore mentioned wall) then it will continue past said barrier to the maximum of its area of effect...

So yes, it would hurt wizard A in the first scenario. (Its right in the last sentence of the spell description)

[Plausible Pseudonym]

Kaouse wrote:

Mage's Disjunction has a duration, actually. It doesn't say it's instantaneous.

The duration is for how long magic items are suppressed. The disjunction of active spell effects is instantaneous, you don't set up a rounds/level spell destroying effect.

[Kaouse]

Hmm, Fireball is a spread effect, not a burst as I originally thought. Rather than Fireball, let's consider something like Channel Energy instead.

As for Mage's Disjunction, after rereading it I believe it only applies to high long items are disjoined when hit by the disjunction.

[Ascalaphus]

Fireball specifically talks about breaking through barriers. Not sure if that principle extends to all area blasts.

[Claxon]

Yeah, I again forgot that fireball explicitly mentioned breaking through barriers because it comes up so rarely since objects take half damage from energy attacks and subtract their hardness from it. Unless you're deliberately trying to break through, no one really bothers to keep track of the damage walls or buildings take.

I don't think how Fireball works applies to other blasts, because the specifically include the line. Which, for as old as the spell is, is likely to tell you it's different rather than as a reminder for how the rules work.

[Pizza Lord]

Claxon wrote:

I don't think how Fireball works applies to other blasts, because the specifically include the line. Which, for as old as the spell is, is likely to tell you it's different rather than as a reminder for how the rules work.

I think it probably does apply to most (exception always exist.) It's not the only destructive area spell to do so. Lightning bolt is similarly written.

It's easy to think that because it's specifically pointed out in a spell rather than generally, such as in the Magic section, that it must be an exception. However, like you mention, it's an old spell and 'back in the day' things weren't always listed out in sections, sub-sections, and erratas. A lot of spells actually set the baseline functions for all other spells. It's similar to how the barkskin spell sets a basis for a creature without a natural armor bonus actually counting as having a natural armor bonus of 0 (which is not where one would think to look if a question about natural armor came up.)

In this case, fireball was considered the de-facto blast-radius AoE spell for a long time and how it works was likely written into it specifically (They didn't use terms like 'burst' or 'spread' back then.) The same deal for lightning bolt in cases of line-effect AoEs. Those spells were the most common and first encountered examples of how those types of spell effects worked.