Question about Line of Effect

[Rel]

Once again, I seek the wisdom of my fellow ENWorlders:

Last night the Druid in the party wished to cast Spike Stones (3.0) down a somewhat irregular stone passageway. He could clearly see the opening of the passageway and that it curved somewhat but both darkness and the natural curve of the passage prevented him from seeing more than around 50 feet down the tunnel. My questions:

1) Can he cast Spike Stones to its full area of effect (eleven 20 foot squares since he's 11th level) even though he can't see where precisely to place those beyond the first two or three? In other words can he say, "I extend it as far down the corridor as it will go."?

2) Is the answer any different if he has been down the corridor before (in this case he hadn't) and knows the layout of the passage from experience?

 

[MichaelH]

IMO, his spell would affect the passageway until the actual line of effect is blocked. Note that line of effect is not blocked by darkness, so the spell should keep affecting the passageway until the passageway itself is blocked (by a wall, door, wall of force, etc.) or it reaches its maximum range. I don't think he needs to be able to actually see the entire passageway for the spell to work.

 

[Rel]

IMO, his spell would affect the passageway until the actual line of effect is blocked. Note that line of effect is not blocked by darkness, so the spell should keep affecting the passageway until the passageway itself is blocked (by a wall, door, wall of force, etc.) or it reaches its maximum range. I don't think he needs to be able to actually see the entire passageway for the spell to work.

I don't strongly disagree with your position, Michael, but it seems like it could lead to some rather odd and potentially abusive situations. If the player can simply indicate that he casts it "down the passage", sight unseen, is there anything stopping him from further defining the area of effect? Can he say, "I cast it down the passage. If the passage forks or there's an intersection, I want the spell to extend down each side passage equally. If there are any rooms along the passage, I want it to fill those too."

If that is allowable, I think it makes spells like this much more powerful. What if you Enlarged it? At that point, a Druid (or Earth Cleric) could walk up to the mouth of a cave, without ever having been inside it, and simply cast this spell inside, effecting the first 8,800 square feet (I'm assuming an 11th level caster like the PC in my group). This renders the cave pretty much uninhabitable for non-flying creatures for the next 11 hours!

I'm leaning pretty strongly away from that interpretation. What I allowed in the actual event was for him to cast the spell "in a straight line down the passage". That meant that it effected an area further than he could actually see or knew about. But the spell did not adapt itself to local conditions without the guidance of the caster. When the passage curved, the effects of the spell did not curve with it.

I'd love to hear any other opinions on this matter.

 

[RigaMortus]

From the SRD

Line of Effect: A line of effect is a straight, unblocked path that indicates what a spell can affect. A line of effect is canceled by a solid barrier. It’s like line of sight for ranged weapons, except that it’s not blocked by fog, darkness, and other factors that limit normal sight.

You must have a clear line of effect to any target that you cast a spell on or to any space in which you wish to create an effect. You must have a clear line of effect to the point of origin of any spell you cast.

A burst, cone, cylinder, or emanation spell affects only an area, creatures, or objects to which it has line of effect from its origin (a spherical burst’s center point, a cone-shaped burst’s starting point, a cylinder’s circle, or an emanation’s point of origin).

An otherwise solid barrier with a hole of at least 1 square foot through it does not block a spell’s line of effect. Such an opening means that the 5-foot length of wall containing the hole is no longer considered a barrier for purposes of a spell’s line of effect.

So the spell would go past (through) the darkness, to it's maximum range, as long as nothing was blocking it. If the tunnel curved, eventually the wall (or ceiling) would block the spell. I don't think the spell can "turn" with the curves of a tunnel.

 

[Rel]

I don't know why it didn't click when I read that before, Riga Mortis. Now that I read it again, I'm not sure why this was even a question.

Thanks.

 

[Coredump]

Well, I may have allowed him to choose an area (ie circle) and had it effect any portions that were in that circle. granted, most of the circle would have been wasted as it is in the wall, but it would have effected the rooms and hallways that were in the circle. (of course, it would have probably affected them also ;-)

 

[Hypersmurf]

I don't know why it didn't click when I read that before, Riga Mortis.

Notice the difference between Spike Stones and, say, Web.

Web affects a 20' radius spread. You only need line of effect to the centre of the Web... so if you were 50 feet up a corridor from an intersection, you could cast Web centred on the intersection, and the Web would affect any space that had line of effect from that centre point up to 20 feet away.

Even though you don't have line of effect to the side passages, they'll still be Webbed.

But Spike Stones doesn't have a "point of origin" - it affects a bunch of 20 foot squares. Strictly, you need line of effect to each 20 foot square you wish to affect.

Arguably, you could affect a 20 foot square that you only had line of effect to a part of - so you could place one 20 foot square at the left-hand edge of the intersection (affecting fifteen feet up the side passage) and one at the right hand edge (affecting fifteen feet up the other side)... but you couldn't extend the spikes any further than that where you don't have line of effect.

Note, though, that line of sight isn't required... so if the passage is straight, but dark, you could lay the spikes out a hundred feet into the darkness, and just hope there's somewhere for them to go...

-Hyp.