Casting through walls. Thoughts welcome!

[Nonlethal Force]

I've got a fairly random question.

PART A:

Do you have to have line of sight to cast a spell? For example, take the following castle layout of 2 20 foot square cells:

|----|
|    |
|    |
/    |  <-- Cell A
|    |
|----|
|    |
|    |
/    |  <-- Cell B
|    |
|----|

Now, suppose a caster in Cell B is really annoyed by the bard's singing in Cell A. Can he cast a spell anywhere in Cell A even though there is clearly a solid wall betwen them? I mean, it isn't like the caster can't figure out the exact distance to place a spell in the center of the room if he assumes that the cells are uniform. [Not always a safe assumption, but we'l go with it for the purposes of this example]

PART B:

What if the walls were no longer cement or stone or wood or whatever. What if now they were walls of force which are transparent. Can a spellcaster cast a spell to take effect on the other side of a wall of force that they can see through?



Thanks!

 

[IcyCool]

Spells usually require both Line of Sight and Line of Effect.

 

[tylermalan]

IIRC, there are some spells that only require one of those two, as opposed to both. But, most spells require both, so in most cases, no.

 

[RangerWickett]

Could he stick his head out the bars of his cell and aim into the other cell?

 

[Nonlethal Force]

Could he stick his head out the bars of his cell and aim into the other cell?

Now there's a man thinking out of the box!

As for the other replies, that's what I thought. Thanks. Any other opinions welcome.

 

[Jack Simth]

With most spells, you need line of effect and line of sight to the point of origin of the spell, and from the point of origin to the limits of the effect (there are whole classes of exceptions).

Suppose the wizard in B wants to cast Fog on the Bard in A.

Well, the cell bars don't block line of effect. He needs a stright line, though, or nearly so. If he can lean through the bars somewhat, he's golden. He casts Fog just outside the bars of the bard's cell, like so

 |----|
F|F   |
F|FF  |
O/FFF |  <-- Cell A
F|FF  |
F|----|
F|    |
F|    |
 /    |  <-- Cell B
 |    |
 |----|

And he gets half of the Bard's cell covered in fog. Fireball works the same way....

 

[starwed]

In regards to the OP, you can't do this because you must have line of effect:

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.

With most spells, you need line of effect and line of sight to the point of origin of the spell, and from the point of origin to the limits of the effect (there are whole classes of exceptions).

Actually, you don't need line of sight for most spells. You can simply declare the origin of the spell with a relative position (such as "100 feet to the north.") If it turns out that there was a wall in the way, the spell will fail: that is the risk you take for doing this.

The only rule requiring line of sight is with regards to targeted spells:

Target or Targets: Some spells have a target or targets. You cast these spells on creatures or objects, as defined by the spell itself. You must be able to see or touch the target, and you must specifically choose that target. You do not have to select your target until you finish casting the spell.

Note that if you're touching something, you can target it even if you don't have line of sight to it.

 

[frankthedm]

Since fireball is an area of effect, the caster chooses an intersection, rather than an actual square. Also since it is a spread, it can it can wrap around corners. My diagram below outlines the square that the fireball lost due to spreading around the corner.

The only real question is if the jail bars would block line of effect down their length. I could see it argued either way.

Does block LOE <<<<<<<< >>>>>>>> Does not block LOE

Spread: Some effects, notably clouds and fogs, spread out from a point of origin, which must be a grid intersection. The effect can extend around corners and into areas that you can’t see. Figure distance by actual distance traveled, taking into account turns the spell effect takes. When determining distance for spread effects, count around walls, not through them. As with movement, do not trace diagonals across corners. You must designate the point of origin for such an effect, but you need not have line of effect (see below) to all portions of the effect.