Radius of a 20 foot spread?

[Infiniteidk]

What is the radius of a 20 foot spread? A player and I were discussing the area of a Dust of Sneezing and Choking, which is described as having a 20 foot spread. I interpret this to mean an area with a ten foot radius, like the Dust of Appearing; but the player said that a 20 foot spread effects only 4 squares (a 5 foot radius) in total because that represents a 20 foot total movement (5 feet in each direction).

[Maezer]

Infiniteidk wrote:

What is the radius of a 20 foot spread? A player and I were discussing the area of a Dust of Sneezing and Choking, which is described as having a 20 foot spread. I interpret this to mean an area with a ten foot radius, like the Dust of Appearing; but the player said that a 20 foot spread effects only 4 squares (a 5 foot radius) in total because that represents a 20 foot total movement (5 feet in each direction).

Without intervening terrian. A 20' spread is the same as a 20' radius. Where a spread is different then a burst or emanation is that you can count the distance from the origin point around walls and other objects that would block line of effect.

[Jeraa]

Infiniteidk wrote:

What is the radius of a 20 foot spread? A player and I were discussing the area of a Dust of Sneezing and Choking, which is described as having a 20 foot spread. I interpret this to mean an area with a ten foot radius, like the Dust of Appearing; but the player said that a 20 foot spread effects only 4 squares (a 5 foot radius) in total because that represents a 20 foot total movement (5 feet in each direction).

Area effect distances are the radius, not diameter. So a 20' spread will effect a total of 8 squares from one side to the other side (everything within 4 squares/20 feet of the origin point).

[Infiniteidk]

Thanks for the responses, just one more question because it came up in the discussion. The spell Shifting Sand lists its area as a 20 foot spread, but Fireball lists its area as a 20 foot radius spread. He used that to mean that there was a difference, is the term radius spread synonymous with just spread then?

[dragonhunterq]

Actually 'radius' is superfluous if not totally meaningless in a rules sense.

Area is measured in all directions from a grid intersection, regardless of the shape of the area. Whether it is a spread or burst just determines how it interacts with cover.
Radius doesn't get mentioned at all.

[Infiniteidk]

Much appreciated all!