# When determining Line of Effect with multiple targets, can you use multiple corners?

So the PHB seems clear with Line of Effect on 1 target at a time: if you can pick a corner and draw a line to any of your target's corners, it's a valid target. But what about when you're targeting multiple people with the same power? For example:

So in this example, its clear by choosing the "northeast" corner of his square, our player can have line of effect on the kobold on the north side of the wall but not the south, and if he chooses the "southeast" corner, he can target the south kobold but not the north. So, if he uses a power that has multiple targets, can he hit both with the same power at the same time? Is that answer different if it's a close burst power? Logically it would seem since each square is 5x5, unless someone was 25 square feet large, the power would originate from the same corner for all targets; if you're in the northeast corner targeting the north kobold, you can't simultaneously be in the southeast corner targeting the south kobold. But obviously logic isn't always the best benchmark for these types of things. If anyone has a non-ambiguous cited answer I'd appreciate it!

• Welcome to the site! Please take a look at the tour and the help; they're a useful introduction to the site. I knew 4e topology is rife with bizarre implications, but somehow I hadn't considered this one. And once you have 20+ rep, feel free to join the chat!
– BESW
Sep 16, 2013 at 22:10
• a thing to note is that for all intents and purposes you are considered to consume your entire space. Everyone is cube. Sep 17, 2013 at 2:50

Yes he has line of effect to both targets for most attacks. You calculate line of effect individually for each target, with one exception.

NOTE: The corner rules mentioned are only for determining cover. They are not used for determining line of effect. Line of effect is calculated based on the existence of any clear line from your square to the target square. Even an arrow slit will do here. (RC 313)

A clear line from one point to another point in an encounter that doesn’t pass through or touch blocking terrain. Unless noted otherwise, there must be line of effect between the origin square of an effect and its intended target for that target to be affected.

For area burst attacks you calculate line of effect to the spot of the attack. And then from the center of the attack. So he would not be able to hit these guys with a burst one or two attack because he does not have line of effect to a square that will have line of effect to both creatures. However, with a burst three attack he can hit them both if he places the attack in the square adjacent to him (I hope it's party friendly, and they'd have superior cover from said attack).

However, for melee, ranged and blast attacks he has line of effect, though they do have cover.

Melee and ranged attacks are determined individually from the attacker to the target. Blast attacks are also determined individually, and although you choose a square for them to begin that is adjacent to you, line of effect is still determined from the origin square (the PC in this case). So cover and concealment will be determined from that square.