If a large creature has a medium creature besides him, does he always have cover to all ranged attacks? A player in my game pointed out that: "the way ranged attacks work is you pick one corner of your square, and target all 4 corners of his, if you have a obstruction... he has cover" Is this true? Does all ranged character always suffer soft cover no matter if they have a direct line of attack to the enemy or not?
The Large creature probably has partial cover (+2 AC)
The player in your group is correct. The Large creature has cover against ranged attacks that come from the side that the Medium creature is on. However, it's probably only partial cover:
If a creature has cover, but more than half the creature is visible, its cover bonus is reduced to a +2 to AC and a +1 bonus on Reflex saving throws. This partial cover is subject to the GM‘s discretion.
(Also, creatures typically only provide soft cover, so the Large creature doesn't get the above bonus to Ref saves nor could he use this cover to make Stealth checks.)
For a Large creature, "more than half the creature" is not very difficult to achieve in a fairly open space because the attacker has two advantages:
- Being able to move, and
- Choosing the corner of his square to draw the line from
If the creatures are arranged so that the Large one has cover at the beginning of the attacker's turn, the attacker can move before attacking to mitigate or remove the cover, even if it's just taking a 5-foot step to one side so that less than half the creature is covered. This is helped by being able to choose the most advantageous corner to use for the calculation. If the Medium creature is covering the left side of the Large creature, use one of your rightmost corners to get around them, and vice versa.