Weak Walls & Line of Sight & Effect (3.5)

[Duke of Urrel]

I think I can figure out whether a transparent or translucent wall blocks line of sight. You can see through a glass window unless there is too much glare, and you can see through gauze if there is more light on your side than on the far side. If the light on both sides of a transparent or translucent wall is roughly equal, assign a miss chance, say 10% for a transparent wall or 20% for a translucent one.

A different and harder question is whether you have line of effect through a soft or weak barrier, such as a cloth curtain or a paper screen. It seems to me that you can easily smash, slash, or shoot through a flimsy barrier like this, so that it offers no cover at all against most weapons. But does it still offer cover against spells?

Must you use the Chain Lightning spell to damage an enemy on the far side of a curtain, or would the basic Lightning Bolt spell or a Fireball blast through it as if there were nothing there?

Is there a rule somewhere that has a better answer to this question than my speculations?

[dwlc2000]

If you can make eye contact, youncan deliver a gaze attack. Or at least in my games.

[Jack_Simth]

I think I can figure out whether a transparent or translucent wall blocks line of sight. You can see through a glass window unless there is too much glare, and you can see through gauze if there is more light on your side than on the far side. If the light on both sides of a transparent or translucent wall is roughly equal, assign a miss chance, say 10% for a transparent wall or 20% for a translucent one.

Line of sight is fairly simple, yes; if you'd be able to see them, you have line of sight. You can have concealment for certain things, like the gauze curtain, no problem, but this is always up for the DM to adjudicate.


A different and harder question is whether you have line of effect through a soft or weak barrier, such as a cloth curtain or a paper screen. It seems to me that you can easily smash, slash, or shoot through a flimsy barrier like this, so that it offers no cover at all against most weapons. But does it still offer cover against spells?
Yes, it'll still stop a spell, although certain spells (such as Fireball (http://www.d20srd.org/srd/spells/fireball.htm) or Lightning Bolt (http://www.d20srd.org/srd/spells/lightningBolt.htm)) will continue through a barrier if they deal enough damage to the barrier to breach it. Something targetted, however (such as Charm Person (http://www.d20srd.org/srd/spells/charmPerson.htm) or Control Undead (http://www.d20srd.org/srd/spells/controlUndead.htm)) is stopped by a barrier that doesn't pass line of effect - which is specifically defined in the Magic Overview (http://www.d20srd.org/srd/magicOverview/spellDescriptions.htm#lineofEffect).


Must you use the Chain Lightning spell to damage an enemy on the far side of a curtain, or would the basic Lightning Bolt spell or a Fireball blast through it as if there were nothing there?

Chain Lightning: Sorry, that thin curtain of clear plastic might as well be a Wall of Force. Chain Lightning does not have the exception that some other spells do (although you could destroy the curtain and get the target the next round; arguably, you could target the barrier as the primary attack, and then have the attack arc to the person behind the wall....)
Lightning Bolt, Fireball: Will explicitly destroy the barrier and continue on like the barrier wasn't there.


Is there a rule somewhere that has a better answer to this question than my speculations?
Yes.

[Duke of Urrel]

...arguably, you could target the barrier as the primary attack, and then have the attack arc to the person behind the wall....)

That is exactly what I was thinking in regard to the Chain Lightning spell. I just wanted to hear somebody else say so.


Lightning Bolt, Fireball: Will explicitly destroy the barrier and continue on like the barrier wasn't there.

I'll admit it; I was lazy. Thanks for the help!

[Duke of Urrel]

I agree with Dwlc2000 that gaze attacks should work through translucent or transparent walls. I would add only that if a translucent wall imposes a miss chance due to concealment, this applies to the gaze attack as well.

I accept everything Jack_Simth said about magical attacks (because hey, he did the work of actually looking up the rules). I also would like to propose the following additions to my musings about mundane attacks.

1. You can smash, slash, or pierce through any barrier with a mêlée attack, at the cost of deducting the barrier’s Hit-Points from the damage you inflict on any creature behind the barrier.

2. A ranged attack follows this rule only if a thrown weapon or projectile weighs 10 pounds for every Hit-Point the barrier has; otherwise, the barrier bestows improved cover, that is, a +8 bonus to the Armor Class of the creature behind it.

3. A falling object that falls straight through a barrier is treated as a mêlée attack.

[Deophaun]

Yes, it'll still stop a spell, although certain spells (such as Fireball (http://www.d20srd.org/srd/spells/fireball.htm) or Lightning Bolt (http://www.d20srd.org/srd/spells/lightningBolt.htm)) will continue through a barrier if they deal enough damage to the barrier to breach it. Something targetted, however (such as Charm Person (http://www.d20srd.org/srd/spells/charmPerson.htm) or Control Undead (http://www.d20srd.org/srd/spells/controlUndead.htm)) is stopped by a barrier that doesn't pass line of effect - which is specifically defined in the Magic Overview (http://www.d20srd.org/srd/magicOverview/spellDescriptions.htm#lineofEffect).
Not necessarily, as the word "solid" is not defined by the game, and there are multiple definitions that can reasonably be applied in this reading. If you read "solid" to mean that phase of matter, then yes, the spell is blocked. If you read "solid" as "firm," then no, the spell goes through it without a problem. Both interpretations are fair game. Ask your DM. Also, keep in mind, solid in the later sense is not a binary sense. A heavy curtain could be solid enough to block a spell, while a gossamer veil of cobwebs would not.

[Jack_Simth]

Not necessarily, as the word "solid" is not defined by the game, and there are multiple definitions that can reasonably be applied in this reading. If you read "solid" to mean that phase of matter, then yes, the spell is blocked. If you read "solid" as "firm," then no, the spell goes through it without a problem. Both interpretations are fair game. Ask your DM. Also, keep in mind, solid in the later sense is not a binary sense. A heavy curtain could be solid enough to block a spell, while a gossamer veil of cobwebs would not.
That is true enough.