Zones/Powers that Block Line of Sight

[AbdulAlhazred]

Think of it this way. Totally obscured terrain is EXACTLY identical to totaLikewise seeing OUT of totally obscured terrain is equally impossible, it blocks all LOS. Where the argument comes in is what do you do at the EDGE of the terrain? 2 corners of a square at the edge of totally obscured terrain are not IN the terrain. By that measure you can see all corners of a square that is outside the terrain from one corner of your square. By that measure, there is no penalty for someone inside the edge looking out.l darkness. Whatever is in the total darkness is invisible. You have a -5 to hit it. The real tricky part comes when you think about what is the effect on the creature IN the cloud. 2 corners of its square are at the edge of the cloud, and it can trace LOS from any corner of its square. Since it can do so to any part of the guy outside the cloud's square, it appears he has no penalty at all.

 

[Nytmare]

Where the argument comes in is what do you do at the EDGE of the terrain? 2 corners of a square at the edge of totally obscured terrain are not IN the terrain. By that measure you can see all corners of a square that is outside the terrain from one corner of your square. By that measure, there is no penalty for someone inside the edge looking out.

No, but that's the thing, and this is where I was making my mistake before. The person on the inside can SEE out just fine because they only have to be able to trace one unobstructed line from their square to the other. But when it comes time to assess penalties, they have to check every corner of their square, which means that at least one of the back corners will have to pass through the square they're standing in.

 

[Goumindong]

No, but that's the thing, and this is where I was making my mistake before. The person on the inside can SEE out just fine because they only have to be able to trace one unobstructed line from their square to the other. But when it comes time to assess penalties, they have to check every corner of their square, which means that at least one of the back corners will have to pass through the square they're standing in.

When it comes to assess penalties for people looking in, not for people looking out

 

[Oompa]

Drawing lines from square to square is for COVER and we are talking concealment..

✦ Concealment (–2 Penalty to Attack Rolls): The target is in a lightly obscured square or in a heavily obscured square but adjacent to you.

So attacking from outside to inside gives you a -2 if you are adjacent, if not -5..

I would rule the same for a vice versa situation..

Someone deep in the cloud can't see someone standing on the outside, but someone standing on the outside can't see deep in the cloud..

 

[SlyFlourish]

Evilbob is right: there are many ways to judge the rules, particularly on Stinking Cloud, wall of fog, and darkness cloud which all seem to have the same effect but are worded differently.

In our game we have determined that it is a perfectly opaque block of stinky cloudiness that cannot be seen out of or into. Anyone attacking into the cloud or within the cloud is at -5. Anyone attacking at the edges of the cloud are likewise at -5. It's -5 all around the cloud.

The more challenging aspect is being pushed into and out of a zone like that. Can you use it as a giant cheese grater by pushing in, pushing out, and pushing in again? I've house ruled that being pushed, pulled, or slid into a zone means the zone does not take effect until the beginning of your next turn. Only if you willingly move into a zone will it take effect right away. This removes the cheese grater effect of zones.

 

[AbdulAlhazred]

The problem is the rules are incomplete.

There are 3 rules sections which deal with the effects of terrain (aside from movement).

Line of Effect - This one is perfectly clear in how it works. Obviously it isn't relevant in the case of a cloud of fog and for all other cases it has exact known rules.

Line of Sight - Again, this one is perfectly clear. In the case of the fog both characters have LOE. Since both characters have an unblocked line to each corner of the other's square there is no cover.

Concealment - There are two parts to the concealment rules. First you have to consider intervening squares. In this particular case none of the intervening squares effects concealment. Second you have to consider the squares the creatures occupy. Here is where the problem lies. The rules on page 280 specify the penalties for a character attacking someone who is IN the square of concealment, so we know that the creature outside the fog attacks anything inside with a -5. There is NO rule for how obscured squares affect the creature which is IN them when attacking things outside. The general reading would thus be that there is no effect. This works fine for the case of darkness, which is the only totally obscuring terrain type listed. You can attack from darkness with no penalties, and intervening darkness has no effect either. The problem comes up because a fog cloud isn't darkness, it actually affects vision THROUGH it, not just into it, which is not covered by the rule on PHB 280. It would be covered by normal LOS rules if the attack passed through a whole square of fog.

Thus my determination would be there IS no rule governing attacking out of a square of fog. None at all. One answer then is there is no penalty since none is specified. I would rule that if this was ordinary obscuring terrain that would be fine (IE light fog or a bush that the creature is inside). With totally obscuring LOS blocking terrain DMs obviously don't think that rule is very good, so give whatever penalty you like. -5 is reasonable on the theory that both creatures are equally hampered. -2 could also be argued on a theory that it is still easier to see out than in and a creature can be considered to be peering out of the corner of its square more or less.

Personally in this one case I'd give a -5 for attacking out, but like I say, it is a purely DM arbitrated situation with no official rule.

 

[Markn]

Evilbob is right: there are many ways to judge the rules, particularly on Stinking Cloud, wall of fog, and darkness cloud which all seem to have the same effect but are worded differently.

In our game we have determined that it is a perfectly opaque block of stinky cloudiness that cannot be seen out of or into. Anyone attacking into the cloud or within the cloud is at -5. Anyone attacking at the edges of the cloud are likewise at -5. It's -5 all around the cloud.

The more challenging aspect is being pushed into and out of a zone like that. Can you use it as a giant cheese grater by pushing in, pushing out, and pushing in again? I've house ruled that being pushed, pulled, or slid into a zone means the zone does not take effect until the beginning of your next turn. Only if you willingly move into a zone will it take effect right away. This removes the cheese grater effect of zones.

This is exactly how we work the spell as well. Additionally, if the wizard sustains the power, moves it over a bad guy, the bad guy will not take damage until the beginning of his turn.

 

[Caliban]

Emphasis mine, if the target is in a heavily obscured square but adjacent to you, it is considered light or partial concealment (-2 to hit).

The spell doesn't reference concealment or obscurement.

It simply states that it blocks line of sight. So, I rule that it blocks line of sight (-5 penalty no matter where you are in the cloud [if you are the one in the cloud], and no matter where your target is in the cloud [if you attack the correct square].)