# Can the Wall of Fire be placed on a vertical solid surface?

The target for the Wall of Fire spell is described as "a solid surface within range", does this imply that the spell could be cast on a wall or other vertical surface (or upside down on a ceiling)? If so, are the specified dimensions (length, height and thickness) measured from the floor or from the target surface?

## Yes - As long as the surface is solid and within range

As you mentioned wall of fire reads:

You create a wall of fire on a solid surface within range. You can make the wall up to 60 feet long, 20 feet high, and 1 foot thick, or a ringed wall up to 20 feet in diameter, 20 feet high, and 1 foot thick.

The only requirement for the surface is that it is both solid and within range.

The phrasing of the dimensions of the wall 20ft high, 60ft long, 1ft thick are specific relative to your scene. Height is in the vertical direction, i.e. if your player makes a high jump this is the direction they would move in. Length and width directions are perpendicular to this (and each other) but for your player to choose.

For example if you cast this on a vertical wall the fire's height would still be 20ft upwards in the direction the wall is moving and the length and depth would be in the plane the floor is in.

• How would you say the dimensions being relative to the scene work together with the ring shaped wall where "thickness" and "height" would be the same direction in some cases?
– Jave
Commented Jul 13, 2021 at 12:15
• @Jave Thickness, width and height should never be the same direction at any individual point on a cylinder. The three are perpendicular to each other. Commented Jul 13, 2021 at 12:31
• @LioElbammalf the ring configuration uses "diameter, height and thickness" instead of "length, height and thickness". The diameter already defines a 2d shape together with the thickness so when the ring is vertical the height will be the same direction as the thickness at the lowest and highest point.
– Jave
Commented Jul 13, 2021 at 12:33
• Commented Jul 13, 2021 at 12:52
• I'm going to accept this answer, but it would be nice with some sort of reference from the rules that the dimensions should be read as relative to the scene.
– Jave
Commented Jul 15, 2021 at 20:18

## The spell has a fixed spatial orientation:

The spell as written assumes a specific orientation of the wall:

You can make the wall up to 60 feet long, 20 feet high, and 1 foot thick, or a ringed wall up to 20 feet in diameter, 20 feet high, and 1 foot thick.

The assumption is that the wall's fixed orientation is relative to worlds general orientation of up down, near and far. (20 feet HIGH / 1 foot THICK / 60 Feet LONG).

Giving the descriptor height applies the automatic definition that the orientation of the spell is vertical along it's Y axis in relationship to the ground which is the X axis. As height is a measurement in elevation in relationship to the center of the earth.

This orientation is reliant upon orientation with the ground, and not the caster. No other alternative formation is given, so this is the only X-Y axis (Height) manifestation of the spell that can occur. The X-Z manifestation can be rotated or transposed (horizontal manifestation).

## It is ambiguous as to whether you can place the wall adjacent to a vertical surface

The idea of placing the wall onto a vertical surface comes down to your reading of the first sentence of the text:

You create a wall of fire on a solid surface within range.

"On" is the key word here. It was not written as "On Top". So there is an argument to be had that you could hang your wall of fire ON another wall (Akin to putting a painting on a wall). Just remember the wall has a fixed height orientation of 20 feet high parallel with the force of gravity. But this is a very nit picky grammatical breakdown of the spell description.

"Hanging" a wall of fire on another wall, arguably, could mean your only able to place it in a single orientation: Parallel to the wall. Granting only one foot in thickness extending away from the wall. The spell seems to imply that the wall must be supported by a solid surface. You cannot run the wall of fire "Up" another wall because doing so would mean you exceed the 20 ft height limitation.

The general conventional reading is that "On" refers to a horizontal surface, or to be placed in contact with the object in a position of superior altitude.