Fibers are collected from plants or animals and can be crafted into useful items like Rope or String. Cotton fiber is harvested directly from mature Cotton Plants in the form of Cotton Bolls. Flax and Jute fibers are obtained by sealing Flax or Jute plants into a Barrel of Fresh Water for 8 hours. Sisal fiber is crafted by crafting Agave with a Knife in the crafting grid. Wool fiber is obtained by shearing a Mouflon or Sheep by clicking Right Click while holding a Knife or Shears. Sheepskin crafted with a Knife will give Wool and Raw Hide.
Jute and Sisal fibers can be woven into Burlap Cloth on the Loom. They do not need to be crafted into String first.
Flax, Jute and Sisal Fibers can also be crafted into Rope by holding at least five of the item in your hand and Right Click on a block. This immediately consumes 5 of the fiber and returns one Rope. Warning: Holding down Right Click will rapidly craft one Rope after another. It is possible to use up a stack of Fibers very quickly this way.
Craft by right-clicking a block
with 5+ fiber in hand.
Cotton, Flax, and Wool fibers can be crafted into String with the Spindle.
Silk does not have a fiber. It drops from Spiders as String. Jute and Sisal are the only fibers that can be used on the Loom without being crafted into String first.