Wall of Fire Placement.

[Nelzy]

Last night in my group a question about the legality of Wall of Fire's Ring variant placement when other objects and walls are around.

Archives of Nethys wrote:

Wall of Fire:

You raise a blazing wall that burns creatures passing through it. You create either a 5-foot-thick wall of flame in a straight line up to 60 feet long and 10 feet high, or a 5-foot-thick, 10-foot-radius ring of flame with the same height. The wall stands vertically in either form; if you wish, the wall can be of a shorter length or height. Everything on each side of the wall is concealed from creatures on the opposite side. Any creature that crosses the wall or is occupying the wall's area at the start of its turn takes 4d6 fire damage.

Since Wall of Fire dont have the "You must conjure the wall in an unbroken open space so its edges don't pass through any creatures or objects, or the spell is lost." that some other wall spells do.

it should be place-able with creatures and objects in its path, placing it on creatures is part of its designs after all.

We use this grid representation of 10ft radius wall
⬜⬜⬜⬜⬜⬜
⬜⬜⬛⬛⬜⬜
⬜⬛⬜⬜⬛⬜
⬜⬛⬜⬜⬛⬜
⬜⬜⬛⬛⬜⬜
⬜⬜⬜⬜⬜⬜

We placed the wall like this. (X is the Wall of Fire and black is regular house walls.)
⬜⬜⬜⬛⬜⬜⬜⬛⬜
⬜⬜⬜⬛⬜⬜⬜⬛⬜
⬜⬜⬜⬛⬜ X , X ⬛⬜
⬜⬜⬜⬛ X ⬜⬜⬛⬜
⬜⬜⬜⬜ X ⬜⬜⬛⬜
⬜⬜⬜⬛⬜ X , X ⬛⬜
⬛⬛⬛⬛⬜⬜⬜⬛⬜
⬜⬜⬜⬜⬜⬜⬜⬛⬜
⬜⬜⬜⬜⬜⬜⬜⬛⬜

https://i.imgur.com/V0RY0lr.jpeg.

as you can see some parts of the wall would be inside or on the other side of the right wall.
and some rule discussions came up, both around if the placement was legal and if the section about making it shorter was applicable to the ring variant.

What is the correct way to handle wall of fire and other walls without spelled-out placement restrictions?

Personally i think we did correct and the parts of the wall that is blocked just fizzles, just like parts of a fireball would fizzle and not cancel the entire spell.

[Castilliano]

I agree with that interpretation re: terrain. The wall springs into existence in the given pattern, save for areas where it cannot. Obstacles breaking the pattern of Wall of Fire, unlike some walls explicitly state, seems to have zero effect on its manifestation. I do have some qualms about if the wall's blocked twice whether I'd let the separate portions both manifest.

If I recall the length of the ring is the length of the line (in terms of squares, and w/o me double-checking) I don't think you can shorten the ring as it's defined by its radius which is neither length nor height, the two parameters the caster controls.
Which is to say, I don't agree with your rendition of a 10' radius (hollow) circle. It implies a 5' radius circle around a point would be...a 10'x10' square? The way you have it is how I'd imagine a 5' radius circle would look; go out 5' safely from center point then there's the circumference of fire. So a 10' radius would go 5' further before fire (filling in corners I believe).

[Baarogue]

I would fill in the corners as well, because not only would you then get the full 60' worth of wall but you'd also get nobody claiming they could cut through the corners unburnt shenanigans

[ReyalsKanras]

Not sure about those fancy tiles, but lets try something. If we look at 10' radius as the interior measurement and then add the 5' wall thickness after that we get a length (circumference) of 60' just like the straight wall. Of course the diagonals would be open but that is easily adjudicated by the GM. If we want the diagonals closed we get way too much fire wall. Hard to call a square a ring, more like a box really.

The four by four might be the intent here. It seems natural to assume the listed 10' radius is the outermost measurement and the rules for counting diagonal distances makes a circle supposedly circular shape with a 10' radius look k%@~ a square. As for adjusting the size, I believe the ring can be adjusted to a three by three or even a two by two if you just wanted some fire. The radius it gives corresponds to the correct total length of fire, I do not think the use of the term radius was meant to disallow adjusting length. Circumference is length, right?

Honestly not sure how to interpret the issue of structures overlapping with part of the ring of fire. The spell does not specify it would fail due to obstruction. Best left up to the GM if any specific obstruction blocks part of the ring of fire, or if it overlaps and burns everything.