Pattern Making, Drafting and Grading
This domain covers the conversion of body measurements into paper patterns. The exam tests blocks, drafting steps, dart manipulation, seam allowances, pattern markings and grading rules.
Pattern types
A block or sloper is a basic fitted pattern with no style details. A working pattern includes design lines, seam allowance and markings. Drafting constructs a pattern from measurements; draping shapes fabric on a dress form.
Drafting rules
Draft on paper with clear grainline, centre front or back, and right angles at key points. Add seam allowance: commonly 1 cm at seams, 1.5 cm at hems, and more where fitting is needed. Mark notches, darts, fold lines and grainline. True the pattern by checking that adjoining seams are equal in length and curves flow smoothly.
Dart manipulation
Darts transfer fullness. Methods include slash and spread, pivot, and dart equivalent. A bust dart can move to the shoulder, armhole, waist or neckline without changing fit.
Grading
Grading increases or decreases a base size using grade rules. Bust, waist and hip usually increase by different amounts because body proportions change. Grade rules must be consistent across all pattern pieces so seams still match.
Worked example
A base blouse block is size 88 cm bust. The brand needs sizes 84, 88, 92 and 96 cm. The pattern maker applies a 4 cm grade across the bust, distributes the increase between front and back and side seams, and checks that the armhole and sleeve cap still match. Reasoning: grading is not simple scaling; each piece must remain compatible with its neighbour.
Traps
Forgetting seam allowance on one piece. Grading only the front and not the back. Ignoring notches and grainline. Moving a dart without closing the original dart. Assuming all sizes increase by the same amount everywhere.
Key points
- A block is a basic fitted pattern; a working pattern carries style and allowances.
- Seam allowance is commonly 1 cm, with deeper hems.
- Darts can be moved by slash and spread or pivot methods.
- Grading uses consistent grade rules between sizes.
- Trueing checks seam lengths and curve continuity.