Sweater Design - Shaping

Shaping

The human body has curvature, but woven fabric is flat and has little elasticity. To produce curvature in a smooth (unruffled) woven fabric, it is necessary to subtract or add wedges of fabric. Positive curvature (cupping, such as is needed at the bust point or over the rear) is produced by subtracting a wedge (a dart) with the point of the dart almost at the point of desired maximum curvature. The greater the angle of the wedge, the greater the local curvature. (The orientation of the dart is unimportant for the curvature, so it can be chosen to accentuate a style line of the garment.) Similarly, negative curvature (ruffling/saddle-shaping, as at a skirt hem, lower back or under the bust) is produced by adding a wedge (a flare). Although the base of individual wedges usually lies on a seam, sometimes wedges occur in pairs (diamonds) that are independent of the seams. Subtracting a diamond-shaped dart produces positive curvature at the outer points of the diamond, and negative curvature at the middle points that are brought together (good for the bust or back). Conversely, adding a diamond-shaped gusset produces negative curvature at its tips and positive curvature at its middle (useful in designing stuffed animals). Sometimes, the sharp, angular edges of the wedges are softened to form continuous princess seams.

Since knitted fabric is generally elastic, it conforms readily to the wearer's body without shaping. However, some shaping may be necessary when the knitted fabrics are unusually stiff (e.g., thick cable designs or heavily overstitched designs) or in regions of high curvature (e.g. sock heels). Ironically, shaping is much easier and less obvious with knitted fabrics than with woven cloth. Instead of cutting out wedges and sewing the edges together, knitters can add or subtract stitches; work short rows; or, most subtly of all, change the needle size to produce smaller/larger stitches in the desired "wedge" region.