Chapter 38: Adjusting for Body Shape & Fit Issues

The basic block drafted in Chapter 37 is a starting template, not a finished pattern — very few bodies match the proportions of a standard sloper exactly, and this chapter addresses the most common adjustments needed to move from block to a genuinely well-fitted pattern.

Common Fit Adjustments

• Full seat adjustment — adding fabric to the back pattern piece through the seat and upper thigh for a fuller seat than the block assumes, typically achieved by slashing and spreading the back pattern piece and adjusting the back crotch curve
• Flat seat adjustment — the reverse adjustment, removing excess fabric from the back pattern piece for a flatter seat
• Full/flat thigh adjustment — widening or narrowing the pattern uniformly through the thigh region, from crotch level to knee
• Swayback adjustment — addressing excess fabric that pools horizontally below the waistband at the back, common on bodies with a pronounced inward curve at the lower back, by removing a horizontal wedge of fabric at the center back
• Forward or protruding abdomen adjustment — adding fabric and adjusting the front dart or pleat placement to accommodate fullness at the lower abdomen without pulling or gapping at the waistband
• Difference between hip and waist proportions — since the standard block assumes a specific waist-to-hip ratio, bodies with a significantly larger or smaller difference between these two measurements require adjusted dart intake or additional side-seam shaping

Diagnosing Fit Problems from a Test Garment

Rather than guessing at adjustments in advance, many pattern makers prefer to sew a first draft in inexpensive muslin/toile fabric (Chapter 15's glossary reference) and fit it directly on the body, identifying and marking problems as they appear — a horizontal pull line typically indicates insufficient fabric in that direction, while diagonal folds typically point toward a length or shape mismatch. This diagnostic approach connects directly to the common fit problems catalogued in Chapter 48.

Working Iteratively

Pattern adjustment is rarely a one-pass process. It is common, and expected, to make an adjustment, cut a new test garment, evaluate, and refine further — particularly for complex combination adjustments (for example, a full seat combined with a swayback, which interact with each other's corrections).

Tip: Photographing a test garment from the front, side, and back — rather than relying on how it feels alone — makes it far easier to accurately diagnose subtle fit issues, particularly in areas like the back crotch curve that are difficult to see directly on one's own body.