Circle
A "circle" is a shape on a square grid that is defined by a center square and a radius. The radius is the number of squares away from the center square that are included in the circle. For example, a circle with a radius of 1 includes the center square and all squares that are 1 square away from the center square.
The exact algorithm for determining which squares are included in a circle is as follows:
- centered on the center of a grid square
- radius measured in units of whole grid squares, e.g. circle 1, circle 2
- a "circle x" is a circle inscribed in a square whose sides are 2x+1 long
- each square that is 50% or more inside the circle is wholly included in the circle
- squares that are less than 50% inside the circle are wholly excluded from the circle
| Circle Size (x) | Circle Radius (x + 0.5) | Number of Squares Included | Squares Added |
|---|---|---|---|
| 1 | 1.5 | 9 | — |
| 2 | 2.5 | 21 | +12 |
| 3 | 3.5 | 37 | +16 |
| 4 | 4.5 | 69 | +32 |
| 5 | 5.5 | 97 | +28 |
| 6 | 6.5 | 137 | +40 |
| 7 | 7.5 | 177 | +40 |
| 8 | 8.5 | 225 | +48 |
| 9 | 9.5 | 293 | +68 |
| 10 | 10.5 | 349 | +56 |
Close Circle
A "close circle" is a circle that is centered on the caster. The caster is included in the circle, and the circle extends outward from the caster's square. Whether or not the caster is affected by the circle depends on the specific power or effect that is using the circle. Some powers may allow the caster to exclude themselves, possibly including all allies or even arbitrary squares, from the circle, while others may require the caster to be affected by the circle.
If not "close", a circle can be centered on any square within range of the power or effect that is using the circle.
Obstacles
Obstacles such as solid walls can obstruct a circle, but sometimes they do not. If an obstacle is fully enclosed by the circle, the circle will wrap around it, although the circle will not penetrate a space fully enclosed by an obstacle.
The rule for this is fairly simple: consider if you were drawing the circle by hand, tracing along its circumference. You cannot cross the boundary of an obstacle, but you can trace around it. If you are able to trace around the obstacle and continue drawing the circle, then the circle will include the squares that are on the other side of the obstacle. If you cannot trace around the obstacle, then the circle will not include any squares that are on the other side of the obstacle.