Stippling is a method for creating textured fills of run stitching which meanders more or less randomly within a border. It can be applied to closed objects with a single stitch angle. You control stitch density in stipple objects by adjusting Stitch length and loop spacing.
Stipple fills are actually made up of a long meandering run stitch. Three types are available – single, stemstitch, and backstitch. Apply them as you would any other fill type.