Spell Radius and Large+ Creatures

[evilbob]

It also seems weird to have a magic circle centered on one corner of a character's square. That would mean it's not really "evenly" distributed, and you'd have to make judgements all the time on whether or not it was in a certain grid corner, or when you could move it around, or whatever. Someone standing 10' from the target may or may not be in their circle, based on which intercetion the circle was currently in. That seems to go against the purpose of the spell (and smacks of "facing" rules).

It's much easier and more intuitive to center it "on the caster." 10' in all directions = 2 squares in each direction, plus each diagonal square and "knight's move." Simple, even, and no question as to who it covers. In fact, it's even simpler if you don't even draw it out but just use the rule "anyone 10' from the target" is effected. It seems like you're just inviting extra bookkeeping doing it the other way.

This way technically hits more spaces at once, maybe (and a lot of those are half-spaces if you want to be really technical), but not more spaces than are possible using all 4 grid intersections.


All that said, the description of magic circle against evil says:

Area: 10-ft.-radius emanation from touched creature

This implies to me that everyone who said "creature's size + 10 feet in all directions" is right. It emenates from the creature; it's not a 10' burst. (I.e. there is no "point" of origin.) This also supports my "non-grid intersection" idea above.

 

[The_Ditto]

All that said, the description of magic circle against evil says:
This implies to me that everyone who said "creature's size + 10 feet in all directions" is right. It emenates from the creature; it's not a 10' burst. (I.e. there is no "point" of origin.) This also supports my "non-grid intersection" idea above.

Check out the rules for a medium sized creature with a reach weapon while mounted on a Large (or larger creature) .... one might consider it a similar precedent as well ... might ...

 

[mvincent]

yes, you can get around antilife shell pretty easily with a reach weapon.

Actually... just noticed that you don't even need a reach weapon. There appears to be no square inside a 10' radius effect that is not adjacent to a square not covered by the effect.

Spells like repel vermin, antilife shell, magic circle, etc. could not keep creatures from threatening their occupant (regardless of the occupant's size).

 

[mvincent]

Could you cite the rules text that demands a single point as the center of emanation?

From the rules:
"The point of origin of a spell is always a grid intersection. When determining whether a given creature is within the area of a spell, count out the distance from the point of origin in squares just as you do when moving a character or when determining the range for a ranged attack. The only difference is that instead of counting from the center of one square to the center of the next, you count from intersection to intersection."

The last sentences appears to indicate that it is specifically not measured like a reach weapon, and the "always" in the first sentence doesn't seem to allow for a different interpretation. I don't like this (and I'm not positive this is what the spell writer's intended on many effects), but that is what RAW says. Personally, I would prefer to have effects that are centered on a creature to actually be centered on that creature.

 

[frankthedm]

See, in that type of situation, I'd just rule-zero it and give the dragons a 5- or 10-ft. radius. It might not be in the RAW, but it makes more sense to me than to get into rules debates about why the dragon can't benefit from such a spell just b/c he takes up more spaces.

There are many spells that don't benefit larger creatures as much as medium creatures in this ruleset.

 

[MarkB]

So, if an emanation is centred on, say, the north-west corner of a medium creature's space when first cast, does it have to stay at that point relative to him as he moves?

If so, is this determined in terms of absolute geographical direction - i.e. always north-west corner since he cast it there?

Or is it determined by the character's orientation - i.e. always in the grid-intersection closest to front-left from his perspective?

If not, how often can the character vary it? Round-by-round? Freely on his turn? Freely on any turn?

 

[IanB]

I've been kicking around a house rule for a while where I'd change all of these 10' emanation type effects to just be "the caster and all adjacent squares" but it hasn't come up enough to be really troublesome yet.

 

[kjenks]

So, if an emanation is centred on, say, the north-west corner of a medium creature's space when first cast, does it have to stay at that point relative to him as he moves?

If so, is this determined in terms of absolute geographical direction - i.e. always north-west corner since he cast it there?

Or is it determined by the character's orientation - i.e. always in the grid-intersection closest to front-left from his perspective?

If not, how often can the character vary it? Round-by-round? Freely on his turn? Freely on any turn?

The rules don't say.

The way I do it: The creature gets to choose which corner the area effect is stuck to. It gets to move this corner to any other corner as a free action at the beginning or end of its turn, unless the creature is helpless.

 

[evilbob]

The way I do it: The creature gets to choose which corner the area effect is stuck to. It gets to move this corner to any other corner as a free action at the beginning or end of its turn, unless the creature is helpless.

I think that's a good way to handle this situation. However, I think having to deal with this situation at all is still "bad." Making up rules to correct/interpret other rules means that the first rule has something wrong with it (in my opinion). Add to that the "I hate facing" personal preference, and you get "don't center some spells on grid intersections because the rule is just wrong."

 

[mvincent]

I've been kicking around a house rule for a while where I'd change all of these 10' emanation type effects to just be "the caster and all adjacent squares"

That would certainly provide better 'all round' protection. I'm just going to continue ruling that area effects that center on an individual do indeed center on that individual (even if that means a slightly greater radius). It makes more sense intuitively (even if it disagrees with the rules).