5 foot radius burst spells vs 5 foot shift

[RealAlchemy]

I encountered a situation the other day where rules as written appeared to contradict common sense. A ninja NPC was tripped, so he stood up (move action) used vanishing trick (standard action) and then took a 5 foot shift. Therefore he had to be within 5 feet of his original square, so logically I concluded a 5 foot radius burst spell (faerie fire) would strike him. This is the point where I found out burst radius spells are targeted on the point between four squares, so a 5 foot burst only covers four squares which means it is possible to miss the target even when I have it localized within 5 feet. Can someone explain the rationale behind this, since I have trouble wrapping my head around the logic?

[Jiggy]

RealAlchemy wrote:

I encountered a situation the other day where rules as written appeared to contradict common sense. A ninja NPC was tripped, so he stood up (move action) used vanishing trick (standard action) and then took a 5 foot shift. Therefore he had to be within 5 feet of his original square, so logically I concluded a 5 foot radius burst spell (faerie fire) would strike him. This is the point where I found out burst radius spells are targeted on the point between four squares, so a 5 foot burst only covers four squares which means it is possible to miss the target even when I have it localized within 5 feet. Can someone explain the rationale behind this, since I have trouble wrapping my head around the logic?

Pretend for a moment that you don't know which direction he went with his 5ft step. Now plot out all the different squares he could be in. You now have a ring of 8 squares (the 9th square being in the center of the ring, where he started).

What's the diameter of that area?

It's 15 feet.

What's the diameter of a 5ft-radius spell?

That would be 10 feet.

As you can now see, the area you're trying to land your spell in is substantially bigger than the area you can cover.

You're trying to use a 2square by 2square spell to cover a 3square by 3square area. Of course there's a chance of "missing".

Does that help?

[Vrischika111]

5 foot burst = circle with diameter of 10 feet.
10 feet = 2 squares.

[DeathMvp]

It is the diffrance of a circle and a donught. Using the dame mass the Circle would be smaller then the Donught as the whole in the center would give you more mass to use spreading the edges out more.

[Jiggy]

Man, now I want a donut. Jerk.

;)

[Seannoss]

As a side note; doesn't standing up count as moving? So a person couldn't stand and take a 5 foot shift in the same round.

[Jeraa]

Seannoss wrote:

As a side note; doesn't standing up count as moving? So a person couldn't stand and take a 5 foot shift in the same round.

You can't use a 5-foot step in a round where you move - that is, go from 1 square to another.

Standing up isn't movement - it is a move action. Those are different things. Not all move actions are movement.

[Barathos]

Seannoss wrote:

As a side note; doesn't standing up count as moving? So a person couldn't stand and take a 5 foot shift in the same round.

It's a Move Action but it isn't the same as a Move Action used to Move.

Chart showing a Move Action and Move as being different things

[Tiny Coffee Golem]

Dont you have to pick the cross hair (square corners, basically) on the map for bursts? So you'd let the enemy pick on of the 4 cross hairs of the square the ninja used to be in. Given that he may or may not hit the ninja.

Is that right?

[That Crazy Alchemist]

Tiny Coffee Golem wrote:

Dont you have to pick the cross hair (square corners, basically) on the map for bursts? So you'd let the enemy pick on of the 4 cross hairs of the square the ninja used to be in. Given that he may or may not hit the ninja.

Is that right?

Yes, it is for this reason that the ninja should move diagonally instead of cardinally that way he has a 25% chance of being hit instead of a 50% chance.

[Cevah]

The ninja should also use Vanishing Trick before standing up to avoid provoking the AoO.

/cevah, better ninja

[kinevon]

Cevah wrote:

The ninja should also use Vanishing Trick before standing up to avoid provoking the AoO.

/cevah, better ninja

Doesn't Vanishing Trick provoke, as well?

Getting the AoO on the stand up part means you don't have to make a concentration check to Vanish later.

[Komoda]

No, it is a swift action and swift actions do not provoke.

[kinevon]

Komoda wrote:

No, it is a swift action and swift actions do not provoke.

That, as it were, is a whole different discussion.

However, it is answered by the ability itself, which is SU, and those do not usually provoke.

Then again, it says "This ability functions as invisibility." which does provoke.

[Gauss]

Another side note: this is not 4th edition, it is a 5 foot step, not a 5 foot shift. :)

[Cevah]

kinevon wrote:

Then again, it says "This ability functions as invisibility." which does provoke.

Except that invisibility does not provoke. Casting it does. You are not casting, but activating a (Su) ability.

/cevah

[Calth]

Jiggy wrote:

RealAlchemy wrote:

I encountered a situation the other day where rules as written appeared to contradict common sense. A ninja NPC was tripped, so he stood up (move action) used vanishing trick (standard action) and then took a 5 foot shift. Therefore he had to be within 5 feet of his original square, so logically I concluded a 5 foot radius burst spell (faerie fire) would strike him. This is the point where I found out burst radius spells are targeted on the point between four squares, so a 5 foot burst only covers four squares which means it is possible to miss the target even when I have it localized within 5 feet. Can someone explain the rationale behind this, since I have trouble wrapping my head around the logic?

Pretend for a moment that you don't know which direction he went with his 5ft step. Now plot out all the different squares he could be in. You now have a ring of 8 squares (the 9th square being in the center of the ring, where he started).

What's the diameter of that area?

It's 15 feet.

What's the diameter of a 5ft-radius spell?

That would be 10 feet.

As you can now see, the area you're trying to land your spell in is substantially bigger than the area you can cover.

You're trying to use a 2square by 2square spell to cover a 3square by 3square area. Of course there's a chance of "missing".

Does that help?

To be fair, that's due to the battle grid system pathfinder uses. Since the game doesn't localize position any more than a square, a "5 foot step" is anywhere from 1 inch to just over 14 feet (going the diagonal). If you were playing a more narrative based game a 5 foot burst centered on where the character was would catch any possible 5 foot step. Basically, due to the abstractions of the game system, a "5 Foot Step" action is not a 5 foot movement.

The treatment of bursts also leads to some really wonky interactions with 5 foot debuff/damage auras. Like the abyssal bloodragers 5 ft fire aura, which by RAW the bloodrager cannot possibly avoid and therefore takes fire damage himself every turn he has it active (since the damage outpaces his fire resistance).

[kinevon]

There is a simple solution, of course, although I don't remember how many levels it adds to the spell: Widen Spell.

On looking, it bumps the spell up three levels, although a couple of traits can reduce that to only a one level bump... For a specific spell.

[Jiggy]

Calth wrote:

If you were playing a more narrative based game a 5 foot burst centered on where the character was would catch any possible 5 foot step.

Only if the ninja is a zero-dimensional point in space and travels exactly 5ft and 0 inches and the spell is targeted exactly on the ninja's starting point without even a fraction of an inch of variance.

Yeah, that sounds a lot more "narrative" than Pathfinder's abstractions.

[Calth]

Jiggy wrote:

Calth wrote:

If you were playing a more narrative based game a 5 foot burst centered on where the character was would catch any possible 5 foot step.

Only if the ninja is a zero-dimensional point in space and travels exactly 5ft and 0 inches and the spell is targeted exactly on the ninja's starting point without even a fraction of an inch of variance.

Yeah, that sounds a lot more "narrative" than Pathfinder's abstractions.

Yes, I would assume that an ability called a five foot step is actually about a 5 foot movement in a narrative system. And the fact that the target has a larger than zero volume helps my point, not hurts it. Cause you know that actually corrects for any slight errors in targeting that you seem so offended by.

[bbangerter]

kinevon wrote:

Komoda wrote:

No, it is a swift action and swift actions do not provoke.

That, as it were, is a whole different discussion.

However, it is answered by the ability itself, which is SU, and those do not usually provoke.

Then again, it says "This ability functions as invisibility." which does provoke.

Functions as X is an entirely different thing than casts as X.