Gathers are created in various ways, most of them taken from sewing. Gathers add softness, fullness, and surface interest.
Gathering using stitching in seam allowance
Gathering using cord or elastic through a casing or a series of eyelets
Shirring using elastic sewn to the fabric usually in evenly spaced rows
Ruching gathers the material into evenly spaced gathers between two points.
The terms are often used interchangeably although each creates a unique look an.d appear differently
