Definition
Nap is a fabric surface that looks or feels different depending on direction, such as velvet or corduroy, so all pattern pieces must be cut facing the same way.
Stroke velvet one way and it feels smooth and looks lighter; stroke it the other way and it feels rough and looks deeper in color. That directional surface is the nap. It comes from raised fibers: pile (velvet, velour, corduroy, faux fur), brushing (flannel, fleece, brushed cotton) or a sheen that reflects light differently (satin, sateen, some knits).
If the pieces of a garment are cut in different directions, they look like slightly different colors once sewn, even though they come from the same fabric. That is why patterns give a with nap layout, in which every piece has its top pointing the same way along the fabric.
How to check and cut:
- Run your hand along the fabric, parallel to the selvedge. Smooth means you are going with the nap, rough means against it.
- Choose a direction and mark an arrow on the wrong side. Corduroy and velvet are often cut with the nap running up, for a richer color; faux fur with the pile running down, so it lies smooth.
- Use the with-nap cutting layout, which usually needs more fabric, often 10 to 20% more.
The same rule applies to directional prints, which have no raised surface but have motifs pointing one way. For fabric quantities, see yardage.