Spell Radius and Large+ Creatures

[Ogrork the Mighty]

If a spell has a radius of 10 feet (e.g., magic circle against evil), do the number of spaces/squares affected change based upon the size of the caster?

Just wondering, cuz if a gargantuan creature were to cast such a spell then the "footprint" of the spell could be smaller than the space of the creature...

 

[Hypersmurf]

If a spell has a radius of 10 feet (e.g., magic circle against evil), do the number of spaces/squares affected change based upon the size of the caster?

No; the point of origin is always a grid intersection.

-Hyp.

 

[Corsair]

Which means colossal dragon + Magic Circle Against Evil= Mostly unprotected against Evil dragon.

 

[Dross]

No; the point of origin is always a grid intersection.

-Hyp.

Huh? I don't think that this is what the OP is asking.

 

[Dross]

Which means colossal dragon + Magic Circle Against Evil= Mostly unprotected against Evil dragon.

While the spell's area of effect doesn't change, if something is not entirely in the AoE, are they still not treated as if they are entirely in the AoE since they still get affected?

So the colossal dragon should be entirely protected by the Magic Circle (if I'm right).

 

[Hypersmurf]

Huh? I don't think that this is what the OP is asking.

As in, the 'point of origin' is not the caster's entire facing.

We don't measure ten feet out from the east side of the human caster's square, and ten feet out from the west side of the human caster's square, for a total diameter of 25 feet; we measure ten feet east and west from one grid intersection, for a total diameter of 20 feet.

Similarly, we don't measure ten feet out from the east side of the ogre caster's 4-square block, and ten feet out from the west side of the ogre caster's 4-square block, for a total diameter of 30 feet; we measure ten feet east and west from one grid intersection, for a total diameter of 20 feet.

Magic Circle Against Evil actually specifies what happens in the case of a colossal dragon:
If a creature too large to fit into the spell’s area is the subject of the spell, the spell acts as a normal protection from evil spell for that creature only.

-Hyp.

 

[ElectricDragon]

Couldn't the colossal dragon just cast Protection from Evil, instead and get the same effect from a lower level spell?

Ciao
Dave

P.S. I see, shorter duration.

 

[Ogrork the Mighty]

That was just an example (and a bad one at that!).

 

[Corsair]

You know, I never actually noticed that line in the Magic Circles before.

 

[Chiaroscuro23]

That was just an example (and a bad one at that!).

Yeah, I think it matters more for AMF, which would let a dragon totally own everyone, if it wasn't smaller than the dragon itself. Though since it's "centered on you" I don't know if "you" is center of mass or what. AMF, unlike magic circle, only affects the part of the creature within the spell. http://www.d20srd.org/srd/spells/antimagicField.htm