About
How PatternFit drafts your pattern
In short: each style is a set of original drafting rules written in code. Your measurements go in, the pattern pieces are computed in your browser (no AI, no server), seams are trued so they sew together, and the PDF is generated at exact millimetre scale. Every release runs over 100 automatic checks.
Ease and fit
| Skirts | +1 cm waist, +4 cm hip; darts take up the waist–hip difference, split front/back. |
|---|---|
| Bodice block | Close-fitting block for woven fabric; waist darts aimed at the bust point. |
| T-shirt | +4 cm (fitted), +10 cm (regular) or +18 cm (boxy) at the bust; sleeve cap solved to the armhole length. |
| Trousers | +8 cm at the hip; back crotch extension longer than front; inseams trued to equal length. |
What the automatic checks verify
- Every style drafts cleanly for sizes XS–3XL (no crossing lines, no missing pieces).
- Seams that are sewn together have the same length: skirt side seams, bodice side seams, trouser inseams and outseams, dart legs.
- Finished waist and hip equal your measurement plus the stated ease (within 3 mm).
- Circle skirt waist arcs add up to your waist plus 1 cm.
- Page sizes are exactly A4, Letter and at least A0.
How printed scale is verified
A sample pencil skirt (waist 72, hip 98 cm) is rendered from the PDF at 10 pixels per millimetre and the lines are measured: the 10 cm square measures 100 mm and the 79 cm waistband measures 790 mm across 3 A4 pages (790.4 mm on Letter). That is the PDF itself; your printer must still be set to 100%, which the free test page lets you confirm.
Original work
The drafting rules and code were written for PatternFit. We do not copy patterns or code from other pattern makers. A drafted pattern is a starting point: sew a test version (toile) before cutting good fabric, especially for the bodice and trousers.