Area spell damage and similar things

[Strife2002]

This is probably an easy one, but when calculating damage for an effect that hits multiple enemies, do you roll damage once and apply it to all creatures, or roll damage for each creature in the effect?

I know for simplicity it's easier to roll once and apply damage to all, and that's probably the answer, but a realist could be justified in rolling damage for each creature caught in a fireball or other area attack.

[wraithstrike]

You roll once. Tell the realist all of the fire has the same amount of power*, except for small pockets of less intensity and finding those is what the reflex save is for.

*It's magic. :)