In garment construction, (also known as flat lining) is a professional technique used to add structure and luxury to a piece without the bulk of a full lining.
It adds body to flimsy or lightweight fabrics like lace or chiffon. underling
It provides a surface for catching hand stitches (like hems or facings) so they don't show on the outside of the garment. In garment construction, (also known as flat lining)
Instead of sewing a separate "inner garment" (lining), you cut your pattern pieces out of both the fashion fabric and a backing fabric (the underlining). The two layers are basted together and treated as a single piece of fabric during assembly. Purpose: Instead of sewing a separate "inner garment" (lining),
Popular choices for underlining include silk organza for crispness, cotton batiste for soft structure, or muslin for general stability. 2. Underling in Pop Culture How to Sew an Underlining - Seamwork
It can hide inner construction details or prevent semi-sheer fabrics from being see-through.