Line of Effect

If a weapon, spell, ability, or item requires an attack roll and has a range measured in feet, it normally requires that you (or whoever or whatever is using the ability) have a line of effect to the target to be effective (subject to GM discretion). A line of effect is a straight, unblocked path that indicates what an attack or ability can affect. A line of effect is blocked by a solid barrier that can stop the effect in question (such as a wall, for most effects), but it is not blocked by purely visual restrictions (such as smoke or darkness). You cannot have line of effect that exceeds planetary range, unless otherwise indicated.

You must have a clear line of effect to any creature or object you wish to target or to any space in which you wish to create an effect without an area. For effects with an area, you must have a clear line of effect to the point of origin of the effect. An effect that is a burst, cone, cylinder, or emanation affects only an area, creature, or object within line of effect from its origin (a spherical burst’s center point, a cone-shaped burst’s starting point, the center point of a cylinder’s circle, or an emanation’s point of origin). For definitions of these specific terms, see Area on page 268.

If you have a line of effect to some of a target’s space but not all of it, the target has cover (see pages 253–254 for more information about cover). Additionally, an otherwise solid barrier with a hole of at least 1 square foot through it may grant cover rather than total cover against an effect, at the GM’s discretion.