In our last gaming session our enemies cast a silence spell. The bard had used Alter Self to a change into an Asabi, one of the few large humanoids. Two of his squares were inside the silence spell, two outside.

I recalled a rule that at least half of a creature has to be inside an area spell to be affected, but I could not find it. I wondered, if that was a 3E rule that had been revised. The only rule I could find was this one:

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.

So: is a creature affected by an area spell in DnD 3.5 if a single square of its space is within the area of effect? Or, if not: how many squares of a 4 square creature does it take to affect the creature?


1 Answer 1


If the far edge of a square is within the spell’s area, anything within that square is within the spell’s area.

This means that if you have a large creature -- which occupies 4 squares -- and any one of those 4 squares are in the area of effect per the above sentence, the creature is affected.

  • 1
    \$\begingroup\$ Ok, so if I got four colossal spiders sitting right next to each other at one grid intersection I get them all with a 5-foot-radius spell like faerie fire. Impressive effect for a small spell. On the other hand - otherwise they would be totally immune to these spells. \$\endgroup\$
    – Giorin
    Commented Feb 24, 2016 at 21:08
  • 1
    \$\begingroup\$ @Giorin Yes, a 5ft radius spell actually hits a 2x2 square area and yes, if there are 4 large creatures who share the intersection that is the center of the area, you'll catch 'em all with it. Pretty nifty, eh? \$\endgroup\$ Commented Feb 24, 2016 at 21:20
  • \$\begingroup\$ Lightning bolt also has a nifty ability that if you cast it down the center line, it hits both sides... \$\endgroup\$
    – MikeP
    Commented Aug 3, 2016 at 20:00
  • \$\begingroup\$ Anything that hits any part of a square, even the edge, affects the entire square, and the entire creature in that square, even when they are large. (rule as written). \$\endgroup\$
    – MikeP
    Commented Aug 3, 2016 at 20:01

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