D&D 3E/3.5 [3.5] Being "within" a spell's Area of Effect

[Dimwhit]

Consider a 20' radius fireball and a 15' base creature. How much of the creature needs to be within the spell's effect to be considered "within" the Area of Effect? All 9 squares of the creature? Half of them? Just one? We can't seem to find anything in the rules or FAQ on it.

We thinking of ruling that the middle point (or square) of the creature needs to be within the area, but I'm wondering if there's something more official.

 

[NewJeffCT]

Consider a 20' radius fireball and a 15' base creature. How much of the creature needs to be within the spell's effect to be considered "within" the Area of Effect? All 9 squares of the creature? Half of them? Just one? We can't seem to find anything in the rules or FAQ on it.

We thinking of ruling that the middle point (or square) of the creature needs to be within the area, but I'm wondering if there's something more official.

I believe any part of the spell effect that catches the size Huge creature would be considered as affecting it.

 

[Theo R Cwithin]

I've never found a definitive ruling. Usually I've just ruled that any creature must be entirely within the AOE for the normal spell effect. For creatures only partially within the AOE, I've given a bonus on its Reflex save (eg, +5?) to avoid, or else simply reduce effect (eg, auto 1/2 damage/healing, etc) - though I don't recall the exact mechanics I used.

 

[StreamOfTheSky]

I believe any part of the spell effect that catches the size Huge creature would be considered as affecting it.

Ditto. No rules reference, but I'm sure that is the rule.

 

[Rhun]

I believe any part of the spell effect that catches the size Huge creature would be considered as affecting it.

This is how I've always ruled.

 

[Edheldur]

From the SRD

Regardless of the shape of the area, you select the point where the spell originates, but otherwise you don’t control which creatures or objects the spell affects. 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.

You can count diagonally across a square, but remember that every second diagonal counts as 2 squares of distance. If the far edge of a square is within the spell’s area, anything within that square is within the spell’s area. If the spell’s area only touches the near edge of a square, however, anything within that square is unaffected by the spell.

 

[Herzog]

Consider this:

a fireball does 1d6/lvl dmg to any creature in the area, where the area is counted in squares

if you include size in regard to whether the creature is in the area (bonus to saving throw etc.), you should also multiply the dmg with the number of squares/cubes the creature occupies....

 

[Dimwhit]

Thanks all. Edheldur's SRD quote is pretty close to answering it completely. Though Herzog, I like that line of thinking! Man, the damage you could do to a colossal dragon...