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Lysander
2010-03-08, 10:33 AM
AMF is an emanation, which allows an archmage to exclude parts of its area from the antimagic effect, correct?

So an archmage could theoretically surround themselves with a sphere of antimagic, but exclude the center, allowing them to cast spells freely and use their buffs? This wouldn't block spells but it would hedge out incorporeal and summoned creatures right? It would also stop them from triggering some magical traps. And creatures relying on magical flight would only be able to drop on you from directly above.

Another tactic would be to shrink the area to just one square adjacent to you. For example if you wanted to have a nearby ally protected against magic, but not cover yourself or everything surrounding you.

Tyndmyr
2010-03-08, 11:00 AM
There's an amusing item in arms and equipment that functions both as magical manacles and an extremely localized AMF. Just covers the wearer.

Doesn't say it takes up any item slots, since obviously, it's intended to be used to imprison casters. Nor does it specify how it needs to be connected to work.

So, clip both bracelets to your favorite beatsticks arm. He now has a permanent AMF that won't screw with your casting.

Optimystik
2010-03-08, 11:37 AM
This issue has come up before, and there's no consensus.

The primary problem is the paradox it generates. If you shape the AMF to exclude the center, then you are effectively turning it off at the source. Logically, this should cancel the entire AMF, rather than creating a magical 'eye of the hurricane' for you to cast your buffs in.

If your DM is willing to overlook that minor problem, there's still others to deal with - the main one you noticed, that casters outside your AMF can pelt anything in at you, from lightning bolts to flame strikes - so long as they originate outside the field, they will enter it, be suppressed, and stop being suppressed in your square, frying you. And note that only incorporeal undead wink out in an AMF; something like the Unbodied or a Psion Uncarnate would be fine in it. If the magical flier is small enough to enter your square (or if they grapple you) they can fly with you and keep all their powers.


There's an amusing item in arms and equipment that functions both as magical manacles and an extremely localized AMF. Just covers the wearer.

Doesn't say it takes up any item slots, since obviously, it's intended to be used to imprison casters. Nor does it specify how it needs to be connected to work.

So, clip both bracelets to your favorite beatsticks arm. He now has a permanent AMF that won't screw with your casting.

Antimagic Shackles were updated to 3.5 in BoED. You're still right, they create a 5-foot AMF. But while they'll protect him, they also suppress the rest of his magical gear.

They are described as "manacles" which in the SRD, "bind" the wearer. Not sure if binding has any associated explicit rules.

Tyndmyr
2010-03-08, 01:02 PM
Antimagic Shackles were updated to 3.5 in BoED. You're still right, they create a 5-foot AMF. But while they'll protect him, they also suppress the rest of his magical gear.

They are described as "manacles" which in the SRD, "bind" the wearer. Not sure if binding has any associated explicit rules.

3.5? Good to know. Yeah, it doesn't work in conjunction with magical gear...but depending on the situation, that may not be a problem. It's one of the interesting ways a melee type can actually limit a casters options fairly strongly. Could also be fun in conjunction with an initiate of mystra.

Im not aware of binding having specific rules associated with it, though the intent is pretty clear.

Optimystik
2010-03-08, 01:40 PM
In an AMF your vestiges stay bound, but it won't help much - most vestige abilities are Su, as are Pact Augmentation and Soul Guardian. In addition, you can't bind any new vestiges, as Soul Binding itself is also Su (and because Expelling a vestige uses the same process as Binding one, you can't get rid of them either.)

Incarnum has a similar problem, IIRC - your soulmelds stay shaped, but turned off.

PanNarrans
2010-03-08, 02:10 PM
Is there a similar item a fighter could use which produces a field with a greater radius?

Curmudgeon
2010-03-08, 02:36 PM
Is there a similar item a fighter could use which produces a field with a greater radius?
Even the standard 10' radius leaves a corner open where a melee opponent can attack the Antimagic Field caster, since all spells have to start at a grid intersection. That still blocks 8 of 9 adjacent squares if we're only considering 5' reach, but AF is pretty much useless against someone with 10' reach.

I don't know of anything other than Widen Spell that makes an Antimagic Field bigger than 10'.

Lysander
2010-03-08, 02:43 PM
This issue has come up before, and there's no consensus.

The primary problem is the paradox it generates. If you shape the AMF to exclude the center, then you are effectively turning it off at the source. Logically, this should cancel the entire AMF, rather than creating a magical 'eye of the hurricane' for you to cast your buffs in.


One way to view it is that you're not shutting off the spell, you're just suppressing its effect in that spot. So the magic is still radiating from you, it just doesn't kick in until 5 feet away.

Can you fire a ray or a burst through an AMF so it affects the other side? If so the "eye of the storm" would work he same way.

Tyndmyr
2010-03-08, 03:35 PM
One way to view it is that you're not shutting off the spell, you're just suppressing its effect in that spot. So the magic is still radiating from you, it just doesn't kick in until 5 feet away.

Can you fire a ray or a burst through an AMF so it affects the other side? If so the "eye of the storm" would work he same way.

Mmmm....maw of chaos?

Curmudgeon
2010-03-08, 04:38 PM
The primary problem is the paradox it generates. If you shape the AMF to exclude the center, then you are effectively turning it off at the source.
That's only a problem if you exclude all four squares around the source. As all spells must originate from a grid intersection, as long as one of the squares around that source point remain in the effect, the spell can emanate without issue.

Optimystik
2010-03-08, 04:55 PM
One way to view it is that you're not shutting off the spell, you're just suppressing its effect in that spot. So the magic is still radiating from you, it just doesn't kick in until 5 feet away.

But that's the problem - if you're suppressing the source, how can anything emanate from it?

That's like wrapping a light-bulb in a towel, and expecting the room to stay bright.

And even if your DM handwaves the shaping, you still run into the other problems I mentioned.


Can you fire a ray or a burst through an AMF so it affects the other side? If so the "eye of the storm" would work he same way.

If there is a safe pocket in the center, all magic will resume there - both offensive and defensive. Any rays, bursts etc. that hit the mage's "live" zone will flare to life there and zap him.


That's only a problem if you exclude all four squares around the source. As all spells must originate from a grid intersection, as long as one of the squares around that source point remain in the effect, the spell can emanate without issue.

There is a crucial exception to this - when the spell originates from YOU, as characters are found in squares and not at grid intersections.

Curmudgeon
2010-03-08, 05:09 PM
There is a crucial exception to this - when the spell originates from YOU, as characters are found in squares and not at grid intersections.
Really? I haven't found such an exception in the rules.
Regardless of the shape of the area, you select the point where the spell originates, but otherwise you donít control which creatures or objects the spell affects. The point of origin of a spell is always a grid intersection. Maybe you're thinking of a house rule?

Optimystik
2010-03-08, 05:20 PM
Maybe you're thinking of a house rule?

No, I'm not.



Area: 10-ft.-radius emanation, centered on you


Your quote is for emanations/bursts that originate from a point in space rather than a creature.

Jothki
2010-03-08, 05:41 PM
Antimagic Shackles were updated to 3.5 in BoED. You're still right, they create a 5-foot AMF. But while they'll protect him, they also suppress the rest of his magical gear.

They are described as "manacles" which in the SRD, "bind" the wearer. Not sure if binding has any associated explicit rules.

What type of action is needed to activate or deactivate them?

Curmudgeon
2010-03-08, 05:57 PM
Your quote is for emanations/bursts that originate from a point in space rather than a creature.
All creatures contact grid intersections. A caster can choose any one of their grid intersections for the origin point of a spell centered on themselves, but there are no exceptions to this rule:
The point of origin of a spell is always a grid intersection.

Kelb_Panthera
2010-03-08, 08:20 PM
What type of action is needed to activate or deactivate them?

The antimagic shackles aren't an activate/deactivate type of item. It's an always-on 5ft amf.

Crow
2010-03-08, 08:50 PM
But that's the problem - if you're suppressing the source, how can anything emanate from it?

Then by your logic, a lightning bolt passing through an anti-magic field is stopped by the field.

The bolt would cease to exist as there would be no more lightning to continue it's path of travel.

taltamir
2010-03-08, 08:56 PM
I see no reason why this wouldn't work... the only problem is with how AMF works this would not be useful.
you can cast spells, enemies can cast spells on you, allied fighters will have their gear useless, enemy fighters will have their gear usless UNLESS they hit you (when the sword hits your square it is no longer suppressed and is magical again).

the only thing it could stop is someone who is flying using magic from coming with a certain range of you, as the AMF will supress their magical flight, causing them to fall down until out of the AMF, whereupon their flight resumes...
However, most magical flight is "self only"... meaning its limited to other wizards. Fly is rounds/CL and can be cast on someone else, so if an enemy wizard casts fly on an enemy fighter he cannot catch you if you have shaped AMF. (well, unless he comes from above, and aims so his falling places him in your square; whereupon his flight resumes and he shares your square;grapple rules ahoy).
Lets also not forget that you exclude 5x5 foot cubes... not a shape of your choosing.

basically, this is an extremely situational ability that usually will harm your party a lot more then the enemy.

Tyndmyr
2010-03-09, 01:11 PM
Then by your logic, a lightning bolt passing through an anti-magic field is stopped by the field.

The bolt would cease to exist as there would be no more lightning to continue it's path of travel.

Not path, source.

Someone IN an AMF cannot cast lightening out of it(barring special circumstances).

Huge difference.

Lysander
2010-03-09, 01:21 PM
Not path, source.

Someone IN an AMF cannot cast lightening out of it(barring special circumstances).

Huge difference.

The question here is whether or not suppressing the origin of an emanation with Mastery of Shaping stops the entire emanation. It's related to the pathing question though.

If you can't exclude the center, then excluding any square in an emanation should stop you from affecting further squares in that direction.

To illustrate poorly, let's say O represents a square, S represents the squares around the source, and X represents a square that has been excluded.

Can you do this with an emanation:

OOOOOO
OOSSOO
OOSSXO
OOOOOO

Or would this happen:


OOOOOO
OOSSOO
OOSSXX
OOOOOX

If the path of the emanation doesn't matter then the center shouldn't matter. If the path does matter, then the center should matter.

Yuki Akuma
2010-03-09, 01:26 PM
All creatures contact grid intersections. A caster can choose any one of their grid intersections for the origin point of a spell centered on themselves, but there are no exceptions to this rule:

Specific trumps general.

AMF says it's centered on you, so it's centered on you.

Optimystik
2010-03-09, 01:59 PM
It is possible for creatures to be centered on a grid intersection (for example, if they are large and take up multiple squares.) But medium creatures are always found within a square, not at one of its corners.

Curmudgeon
2010-03-09, 03:01 PM
AMF says it's centered on you, so it's centered on you. It is centered on you. You have complete freedom to pick any of your grid intersections for its origin point. (It's not like creatures fill their spaces or occupy just the middle of squares; they move around. You get to pick which grid intersection you like best.)

What Antimagic Field is not is centered anywhere other than a grid intersection, because D&D doesn't allow that. Check all the spell targeting rules, in both the Player's Handbook and Rules Compendium. Check the helpful spell area shapes at the back of the DMG. Check the "Rules of the Game" article (http://www.wizards.com/default.asp?x=dnd/rg/20040824a) that covers the same topic. There are no non-intersection exceptions to where spells are centered.

Optimystik
2010-03-09, 03:03 PM
It is centered on you. You have complete freedom to pick any of your grid intersections for its origin point.

Invalid. Your grid intersections are not you.


Check the "Rules of the Game" article (http://www.wizards.com/default.asp?x=dnd/rg/20040824a) that covers the same topic. There are no non-intersection exceptions to where spells are centered.

How does that article invalidate "centered on you?"


Burst or Emanation: The area extends from the point of origin in a sphere whose radius is specified in the entry (though some bursts are cone-shaped areas).

Medium creatures can't stand on an intersection.

herrhauptmann
2010-03-09, 03:09 PM
They are described as "manacles" which in the SRD, "bind" the wearer. Not sure if binding has any associated explicit rules.

In this case, "binding" is not a reference to the binder class. Putting regular shackles on a person binds them (as in "Bound and gagged") unless they can break or slip out of them somehow.

Curmudgeon
2010-03-09, 03:21 PM
Invalid. Your grid intersections are not you.
...
Medium creatures can't stand on an intersection.
Not in real world geometry, but in D&D geometry they do.
Area: 10-ft.-radius emanation, centered on you
You appear to be reading this as if it said "centered on your center" instead of "centered on you". You, in D&D geometry, occupy all of your grid intersections, even though that's physically unrealistic. You can pick any of these grid intersections for the origin point of Antimagic Field.

There's no conflict with any of the rules here; just a difficulty of thinking in D&D geometry rather than Euclidean geometry.

Tyndmyr
2010-03-09, 04:35 PM
In this case, "binding" is not a reference to the binder class. Putting regular shackles on a person binds them (as in "Bound and gagged") unless they can break or slip out of them somehow.

The bright side is, at least in A&E, one is not a requirement for the other. It merely said that if it's clasped on you, the antimagic effect works. I could see a reasonable argument for clasping it on you in a non-binding way.

You are, by default, at medium size or smaller, considered to be in your square. Not at a grid intersection. There is no guarantee that you will take up the entire grid section, and thus be at all points simultaniously. In fact, the rules seem to indicate that this is not the default. I'd find it hilarious to see you justifying how a tiny creature occupies all of a 5ft by 5ft by 5ft cube.

Since specific overrides general, the AMF emanates from you. Not an intersection near you.

Kalirren
2010-03-09, 05:32 PM
A Tiny creature doesn't occupy its entire square, though; that's also explicitly stated.


Very small creatures take up less than 1 square of space.

So I'd rule that a tiny creature is only considered to be inside a spell's AoE if the entire square it's in is within the AoE.

The cover rules seem to agree with Curmudgeon's intersection model.

Curmudgeon
2010-03-09, 07:45 PM
There is no guarantee that you will take up the entire grid section, and thus be at all points simultaniously.
You don't need to be at all points; you just pick one from those you have access to.

I'd find it hilarious to see you justifying how a tiny creature occupies all of a 5ft by 5ft by 5ft cube.
It doesn't need to fill the square; it just needs access to one of that square's four grid intersections. And since it has access to all of them (i.e., 0' of D&D movement required to get there), the creature's size isn't an issue.

Since specific overrides general, the AMF emanates from you. Not an intersection near you.
And where are you, then? You're not fixed at the center, or any other part, of a square; D&D doesn't have rules for that. You do have access to all intersections of your area on the battle grid. Specific language only overrides general rules when there's a conflict, and there isn't one here. An Antimagic Field is centered on you, and you can pick any of your grid intersections to conform to the origin point required for all such spells. There's absolutely nothing that says the spell originates from the geometric center of your square(s), nor even a concept allowing something like that anywhere in the D&D rules.

Lysander
2010-03-09, 08:05 PM
I have to go with curmudgeon on this one. The intersection rule applies to all spells originating with you, including rays and cones. You are also the source of those. Check out what that article says about cones:


Cone: A cone is a quarter circle that extends from the caster's space for the distance stated in the entry. If the caster's space fills only one square, the cone can start at any corner of the space (that corner is the spell's point of origin).

That seems to support the idea of a caster being able to have their spell originate from any corner of their square.

Back to the original topic of the thread though, that same article says this:


The rules don't tell you what to do when whatever blocks the spread's line of effect isn't a solid object (for example, an antimagic field). In this case, just the treat the antimagic field like a solid obstacle.

So according to him the hollowed-out AMF trick would grant you immunity to damage from spreads originating outside the field.