Is the boarder part of the square?

[0-hr]

The 3.5 lightning bolt is now a "line" spell. (PHB 176) You pick a corner on the caster's square and an intersection somewhere else. The spell then affects all of the squares that the line passes "through" (within range).

The diagram on pg. 134 of the PHB shows a "square" and also points out the "border". It's not clear if these are the same thing or not.

So the questions: "If you shoot a lighting bolt down the border of a line of squares, does it affect those squares on either side?"

If so, then you can (in effect) get a 10ft wide bolt, but only when shooting in exactly North-South or East-West lines (must have something to do with the magnetic poles) .

If not, then you can shoot a bolt between people in two adjacent squares without affecting either.

Both results are kind of wonky IMO.

 

[James McMurray]

I would have the caster choose which side they wanted their bolt to effect.

 

[Nifelhein]

I would rule that the character would actually aim from the middle of his own square and, in case this is a problem, to the middle of another square... this means no problems.... at all.

 

[allenw]

The "line" effect description (PHB p. 175-176) specifically says that it starts from "any corner of your square," not the middle.
The text description (duplicated in the SRD) is somewhat ambiguous, but the explanatory "Line Attacks" illustration and *it's* text (PHB p. 176, *not* duplicated in the SRD) makes it clear: the border of a square *is* part of a square, and any square that a line attack touches (even if just at a corner) is included in the area of effect. The illustration shows (among other things) that all 4 squares around a grid intersection that the line passes directly over are affected. The illustration's caption reads:
"A line describes some kinds of attacks [usually magical]. It affects creatures or characters in a straight line away from the spell-caster's square to any intersection within range. All squares through which the line passes or touches are affected by the attack. The line continues to its full range, usually beyoind the target intersection and possibly affecting more characters or creatures."
There's a very useful diagram partway down this page:
http://enworld.cyberstreet.com/showthread.php?s=&threadid=58809&perpage=20&pagenumber=2

Think of it this way: a Lightning Bolt is "really" about 5' wide, but it can affect any square that any part of it extends into, so if you send it straight down the line between squares, it'll affect a path 2 squares wide. If you send it from the upper-left-corner of your square to the upper-right-corner of the square 120' above you, it'll only affect a path one square wide (except at the very end), since all of the line is contained within that path. And if you send it on a 45 degree diagonal, it'll affect a path that's alternately one and two diagonal squares wide.

 

[James McMurray]

That's an excellent description of how the rules work, but it ends up making the spell effectively wider when cast on a straight line. Perhaps that was intentional (most dungeons use 90 degree angeles and 10' wide corridors).

 

[Nifelhein]

allenw,

Hey! Great explanation, I have yet to read that page, as I am currently reading the PHB and am using a hybrid of the 3.X versions. So it was intentional after all... thanks for the info, mind you!

 

[0-hr]

OK, the fact that all 4 of the squares around the target intersection are hit proves that even that single point (the intersection) is enough to include the whole square. Otherwise only 2 of those squares would be darkened.

Thanks. I had looked at (and read) that picture but didn't notice that detail.

BTW, this also has a bearing on cover. You often trace a line of cover along a border (when shooting north, south, east, or west). Since that border is part of the square, a creature in the bordered square does provide cover.

 

[Staffan]

That's an excellent description of how the rules work, but it ends up making the spell effectively wider when cast on a straight line. Perhaps that was intentional (most dungeons use 90 degree angeles and 10' wide corridors).

Actually, you get more or less the same number of squares when sending it on a straight diagonal - possibly two squares less, depending on if it "expands" right from the start (i.e. whether three of the squares adjacent to the caster are hit by the bolt, or just one)