invisible wall and spell

[Dyslexic]

What's happen if we have an invisible wall between a caster and the target?

-The spell fail? (In this case, the caster is aware about the cause?)
-The spell (if is an area spell) take as origin the wall?
-Other?

[The Evil DM]

what's happen if we have an invisible wall between a caster and the target?

-the spell fail? (in this case, the caster is aware about the cause?)
-the spell (if is an area spell) take as origin the wall?
-other?

The result can be different depending on the type of the spell.

I am going to assume a wall that is infinitely thin like a wall of force.

A ray spell that starts at the caster and moves towards the target hits the wall.

A spell that only relies on LOS to a point might work or may not depending on spell. I generally interpret LOS as "You can see the point" if they can see a legit target point and the spell manifests at the point then it is ok. But if the spell is like fireball that has a ray like component the spell hits the wall.

Area of effects cannot go through the wall but might wrap around.

[Dyslexic]

Ok, thank you.

And what about if a spell require LoE and is not a ray? (There are spell like this, I think)

The spell hits the wall or simple fails?

[DrKerosene]

The spell hits the wall or simple fails?
Yes, if it is a solid wall.

If the wall has holes, like a Cage of Force, the spell might work.

[Crake]

Most spells will require line of effect in addition to line of sight. For line of effect to be able to pass through a 5 ft square of an otherwise solid barrier, it requires a continuous hole of at least 1 square foot to allow a spell to pass through. This means that almost every spell you try to cast at a target beyond the wall will be blocked by said wall. Anything that originates beyond the wall will simply fail to manifest, and anything that originates from you will visibly collide with the wall. In the former case, as to whether or not the caster realises the reason for the failure of the spell, it's not entirely certain, so I believe that falls into the land of DM jurisdiction, unless someone knows of a rule I'm not aware of?

[JDL]

Technically casting a spell at an invisible wall and having it blocked would qualify as interaction. It would get a reactive Spot check, DC 40, to spot the invisible wall effect. You could also argue that the character would also be entitled to a Spellcraft check, DC 20+spell level, to identify the Invisibility spell that's in place.

[The Evil DM]

I stand corrected.

According to 3.5 RAW crake is correct all spells require LOE to initial target point. My own interpretation of LOS vs LOE varies from the canon and not all spells require LOE.

There are a few exceptions and the spells indicate "You don't need LOE" Clairaudience/Clairvoyance is one.

[JDL]

The fun you can create with a few permanently invisible iron walls is amazing. They also make awesome windows for your party's fortress.

[Crake]

I stand corrected.

According to 3.5 RAW crake is correct all spells require LOE to initial target point. My own interpretation of LOS vs LOE varies from the canon and not all spells require LOE.

There are a few exceptions and the spells indicate "You don't need LOE" Clairaudience/Clairvoyance is one.

I think the main reason for this is that divinations are actually capable of providing line of sight to something, so being able to cast, say clairvoyance into a closed room, and then being able to use that line of sight to cast sleep in the room would be quite powerful. I hope you don't allow things like that in your game?

[The Evil DM]

I define LOS as direct, being able to perceive remotely does not equal LOS. That said

I allow for all sorts of things in my game that are not standard.

There is a voodoo potion that is expensive and difficult to make. (note I don't do burn xp and a few gold to make a potion, all alchemy uses old school brewing rules and rare ingredients)

If you have the voodoo potion and a drop of blood from a victim it allows for you to:

a) Mix the blood into the potion
b) drink the potion
c) target any enchantment or necromancy spell on yourself but have the effect hit the individual who's drop of blood you used. Range is one mile. No LOS, No LOE.

Makes great fun for murder mysteries.

If a player wants to spend massive time and money to research a level 9 divinations he can cast sleep spells through - but it will take you 18 months and lots and lots of resources.

(note I also use old school spell research rules)

But in the end you have a special and devious tool to use.

Standard divinations do not allow spells to be cast through them and range limits do still apply.

Taking a quick look through the 3.5 PHB for spells that target a point, creature or area which I allow to target in this manner are:

Color Spray - assuming the caster is close enough to the wall
Hypnotic Pattern - Creatures who might see the pattern through the wall could be affected.
Prismatic Spray - beams of light

In my world Invisibility is equated to transparent. And even materials we see as solid to us can be transparent to various forms of energy.

A reasoning I use is apparent in walls of force. Gaze attacks can pass through a wall of force. Therefore I allow other forms of visible light to pass through invisible barriers as well.

That said, My favorite walls are one way invisible walls. They appear solid from one side and invisible from the other.

[Eloel]

What's happen if we have an invisible wall between a caster and the target?

-The spell fail? (In this case, the caster is aware about the cause?)
-The spell (if is an area spell) take as origin the wall?
-Other?

I'd say for anything like a Fireball, the Fireball explodes on the surface of the wall in most cases. Is it RAW? Probably not. The "Hey, I can't cast on those dudes over there" realization should need some sort of fizzling at the very best - I'd not give the caster free knowledge on him not having LoE to other side.

[Crake]

I'd say for anything like a Fireball, the Fireball explodes on the surface of the wall in most cases. Is it RAW? Probably not. The "Hey, I can't cast on those dudes over there" realization should need some sort of fizzling at the very best - I'd not give the caster free knowledge on him not having LoE to other side.

That's actually entirely raw, because the fireball spell produces a small bead that flies out to the location of the explosion, and it says specifically if it comes into contact with anything along the way, it explodes. So in this case, it would hit the wall and explode

[atemu1234]

That's actually entirely raw, because the fireball spell produces a small bead that flies out to the location of the explosion, and it says specifically if it comes into contact with anything along the way, it explodes. So in this case, it would hit the wall and explode

Possibly making the caster into crispy bacon.