Pattern Drafting
What the domain tests
Pattern Drafting tests your ability to turn body measurements into a flat block or garment pattern with correct ease, grainline, darts, seam allowance and balance marks. Expect drafting calculations, dart manipulation and trueing checks.
Core rules
Use a basic block close to the body, then add design ease and wearing ease. Mark the straight grain parallel to the centre front or centre back. Add seam allowance only after the block is trueed; typical allowances are 1.5 cm at seams and 4 cm at hems. Darts transfer fullness; they should point to the bust point or shoulder blade but stop short of it. Notches and balance marks must match at seams.
Worked example
A bodice block uses bust 92 cm, waist 74 cm, with 6 cm bust ease and 2 cm waist ease. Half-bust = 46 + 3 = 49 cm; half-waist = 37 + 1 = 38 cm; difference = 11 cm. Distribute the 11 cm as 4 cm at the side seam (2 cm each side), 3 cm in the back dart and 4 cm in the front dart. Reasoning: the side seam removes width at the underarm, while front and back darts shape the waist without distorting the side seam. True the waistline into a smooth curve after closing the darts on paper.
Traps
Forgetting ease gives a block that cannot be worn; adding seam allowance before trueing creates mismatched seams; a grainline drawn at an angle causes twisting; darts that reach the bust point create a point; not checking front and back side-seam lengths causes puckering.