Effect
Some spells create or summon things rather than affecting things that are already present. The caster must designate the location where these things are to appear, either by seeing it or defining it. Range determines how far away an effect can appear, but if the effect is mobile it can move regardless of the spell’s range.
Ray: Some effects are rays. The caster aims a ray as if using a ranged weapon, though typically the character makes a ranged touch attack rather than a normal ranged attack. As with a ranged weapon, the character can fire into the dark or at an invisible creature and hope to hit something. A character doesn’t have to see the creature he or she is trying to hit, as with a targeted spell. Intervening creatures and obstacles, however, can block the caster’s line of sight or provide cover for the creature being aimed at.
If a ray has a duration, it’s the duration of the effect that the ray causes, not the length of time the ray itself persists.
Spread: Some effects, notably clouds and fogs, spread out from a point of origin to a distance given in the spell description. The effect can extend around corners and into areas the caster can’t see. Figure distance by actual distance traveled, taking into account turns the spell effect takes. The caster must designate the point of origin, but need not have line of effect (see below) to all portions of the effect.