When describing rib patterns, we often speak of the rib
pitch. This is simply the distance between adjacent ribs, and
is often designated by measuring rib center to rib center. The
orientation of the ribs can occur from various combinations.
The most common are the straight ribs, which run parallel
to the end of the separator. The rib orientation can be sinusoidal
[2], diagonal, cross-directional (perpendicular) to the
rib [3], segmented [4] or a “fishbone” pattern (Fig. 3). Delving
deeper, the shape of the individual rib can be defined
by the height, width at the base, and the top and draft
angles