Areas of Effect

Many spells and other features refer to areas, such as cubes, cones, and spheres. A description of each area is given below.

Areas either appear within a specified range or emanate from a source. When appearing within a range, at least one point in the area must be within range, and the area extends through cover. Cover blocks emanated areas, however. A point in space is excluded from an emanation if all lines between that point and the source intersect total cover; half and three-quarters cover may similarly apply. Emanations that spread around cover require an arbitrary path connecting the point in space and the source instead of a straight line. See an area's description for the geometry of its emanation. An emanation's source is assumed to be a point or a convex volume, typically a creature's space.

If enough of a target's space lies outside of an area, the target may benefit from half or three-quarters cover against the area's effect, as appropriate. This includes instances when an area is too small to entirely enclose a target, such as a Medium target at the narrow end of a cone (half cover) or a Large target in a typical line (three-quarters cover).

Some areas establish zones, which are lingering effects that retain the original area's shape. An emanated zone moves with its source. A target suffers a zone's effects when it triggers the zone, benefitting from cover as appropriate if the target is only partially within the zone. Different zones are triggered at different times:

A burst is an emanated sphere-like shape that optionally excludes its source from the area. A burst must be centered on a source, and the burst's size is defined by how far it extends from the source and the size of the source itself. For example, a 5-foot burst emanating from a Medium creature would be 15 feet across, while a 5-foot burst emanating from a Large creature would be 20 feet across. Unless otherwise specified, the creator of the burst chooses whether to include the source in the area or not.

An aura is a zone formed by a burst.

A cone is a portion of a sphere with a size defined by the radius of that sphere. The diameter of a cone's cross-section equals the distance from the cross-section to the center of the sphere. For example, a 15-foot cone extends 15 feet from a point, forming a 15-foot-diameter circle at one end. The cone's creator chooses its orientation. When a cone emanates from a source, the pointy tip of the cone must touch the source, and the cone can't contain any part of the source.

A cube's size is defined by its side length. For example, the edges of a 15-foot cube are all 15 feet. When a cube emanates from a source, the source must touch any point on the cube's surface, and the cube can't contain any part of the source. The orientation of the emanated cube is otherwise up to its creator.

A cylinder's size is typically defined by its height and radius. For example, a 20-foot tall, 20-foot-diameter cylinder has a height and diameter of 20 feet, and a radius of 10 feet. Cylinders are always oriented vertically. When a cylinder emanates from a source, the source must touch a point on the top or bottom of the cylinder, and the cylinder can't contain any part of the source.

A line is a long, straight area defined by its length. A line is 5 feet thick and has a circular cross-section unless otherwise specified. For example, a 10-foot line is a cylinder 5 feet in diameter and 10 feet long. The line's creator chooses its orientation. When a line emanates from a source, the source must touch one point at the end of the line, and the line can't contain any part of the source.

A sphere's size is defined by its diameter unless otherwise specified. For example, a 20-foot sphere has a radius of 10 feet and a diameter of 20 feet. When a sphere emanates from a source, it is centered on a point within that source, containing part or all of the source.

A wall is a long, tall area defined by its length, height, and thickness. Additionally, the wall's creator can choose for the wall to be straight or curve in a circular arc, where the length of a thick, curved wall is measured along the inner surface. The wall must be vertical and its base must be at the ground, however. For example, a 30-foot long, 10-foot high, 5-foot thick wall could be curved to enclose a roughly 10-foot diameter region (note that the diameter of a circle is about one third of its perimeter), and its thickness would cause the structure to be a total of 20 feet across. Like a line, when a wall emanates from a source, the source must touch one point at the end of the wall, and that end of the wall can't contain any part of the source. If the wall curves back around to the source, that end of the wall includes the source, however.