Since the walls of a corridor or small room would provide total cover for anything beyond them, the spell's actual area of effect is limited by the size of the corridor. To block one of these imaginary lines, an obstruction must provide total cover, as explained in chapter 9. If no unblocked straight line extends from the point of origin to a location within the area of effect, that location isn't included in the spell’s area.
Fire ball effects how to#
Specifically, I'm interested in understanding how to interpret the rules in this case.įrom the Area of Effect section on page 204 of the PHB: So in a corridor, would you only affect a 40-foot diameter, and the extra energy that would create the rest of the sphere just never materializes (the effect is blocked by the walls of the corridor)? Or do I calculate the volume and fill that much space in the nearby corridors? How does fireball's AoE work when cast in a corridor or small room, according to the rules of the game?Īre we expected to just lose all the extra area of effect? Or does the fireball expand outward to fill its full normal volume? Similarly, if casting that same fireball in a small room or a corridor, wouldn't that affect people further than 20' radius around? If I think in terms of the law of physics, I would assume that for a fireball cast with its center on the ground, all the energy which is expected to go down has to go somewhere else. (We can actually see an example of the area here:Ģ0 foot square versus a 20 foot circle on a battle mat) In most cases, that is applied at ground level, since that's where most creatures are. The fireball spell is clearly described as a sphere with a 20-foot radius.