You
can specify whether a compound path is a nonzero winding path or
an even‑odd path.
- Nonzero winding fill rule
-
Uses mathematical equations to determine if a point is outside
or inside a shape. Illustrator uses the nonzero winding rule as
the default rule.
- Even-odd fill rule
-
Uses mathematical equations to determine if a point is outside
or inside a shape. This rule is the more predictable rule because
every other region within an even‑odd compound path is a hole, regardless
of path direction. Some applications, such as Adobe Photoshop, use
the even‑odd rule by default, so compound paths imported from these
applications will use the even‑odd rule.
Self-intersecting
paths are paths that intersect themselves. You can choose
to make these paths either nonzero winding or even‑odd, depending
on how you want them to look.

Self-intersecting path with Use Non‑Zero Winding Fill Rule
(left) compared with Use Even‑Odd Fill Rule (right)
When
you create a nonzero winding compound path, you can specify whether overlapping
paths appear with holes or are filled by clicking a Reverse Path Direction
button in the Attributes panel.

Fill rules
- A.
- Four circular paths
- B.
- Circular
paths selected, converted into compound path
- C.
- Reverse
Path Direction applied to innermost path