Area of Effect
Don't confuse Rules for Targeting a Spell with a spell's "Area of Affect." While you can't be targeted by a spell if you are behind total cover, you can still be affected by the spell. As described in the PHB:
"A target with total cover can't be targeted directly by an attack or a spell, although some spells can reach such a target by including it in an area of effect."
Note the word "Some." As described in the PHB: "A spell's effect expands in straight lines from the point of origin. 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. To block one of these imaginary lines, an obstruction must provide total cover, as explained in chapter 9."
In some cases (Like fireball), the spell specifically states that the area of effect spreads around corners and as Jeremy Crawford said: "Your cover is foiled if an effect spreads around it and reaches you."
In almost every case of a spell (see any Ray, or spray, or cone spell) the description start with “….emanates from you.” In those cases we apply the cover rule as described above. The same would be true of dragon's breath as it is clearly emanating from a single point and the effect does NOT state that it spreads around corners.
A few spells do not say "Emanate from you" but simply something like "spring into existence" or "surround you." In those cases cover may not apply.
Note the word "Some." As described in the PHB: "A spell's effect expands in straight lines from the point of origin. 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. To block one of these imaginary lines, an obstruction must provide total cover, as explained in chapter 9."
In some cases (Like fireball), the spell specifically states that the area of effect spreads around corners and as Jeremy Crawford said: "Your cover is foiled if an effect spreads around it and reaches you."
In almost every case of a spell (see any Ray, or spray, or cone spell) the description start with “….emanates from you.” In those cases we apply the cover rule as described above. The same would be true of dragon's breath as it is clearly emanating from a single point and the effect does NOT state that it spreads around corners.
A few spells do not say "Emanate from you" but simply something like "spring into existence" or "surround you." In those cases cover may not apply.
