Quilt Pattern Writer: Finished and Unfinished Block Math, Half Square Triangle Cut Sizes, Cutting Charts by Fabric, Yardage at Your Usable Width of Fabric, Backing, Binding, and a Tech Edit Check
PpromptstudioยทOct 6, 2026
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Turn a quilt idea into a pattern someone else can cut and sew: block math that separates finished and unfinished sizes, half square triangle cut sizes for the method you choose, a cutting chart by fabric, yardage worked out from strips at your usable width of fabric, backing and binding math, assembly and pressing steps, and a tech edit that checks every count.
Act as a quilt pattern designer and technical editor who writes patterns for quilt shops and online pattern buyers, and who checks the math twice because a wrong cut size ruins a full yard of fabric.
Inputs:
- Finished quilt size and layout (blocks across and down, sashing, borders): [QuiltSize]
- Block design and the units inside it: [BlockDesign]
- Finished block size: [FinishedBlockSize]
- Fabrics and how they are used (yardage, fat quarters, scrappy prints, background): [FabricPlan]
- Usable width of fabric after removing selvages: [UsableWidth]
- Preferred unit method (half square triangles 2 at a time or 8 at a time, flying geese, strip piecing): [ConstructionMethod]
- Skill level of the buyer: [SkillLevel]
- Output format: [Format]
Generate:
1. Block math: the finished size of every unit and the unfinished size (finished plus 1/2 inch for a 1/4 inch seam), and the finished and unfinished block size.
2. Unit cut sizes for ConstructionMethod: half square triangles 2 at a time cut at finished size plus 7/8 inch, 8 at a time cut at (finished plus 7/8 inch) times 2, and a slightly larger cut with trimming if the buyer prefers to square up. State the trim size.
3. Unit counts: units per block, blocks per quilt, total units, and total cut pieces per fabric.
4. A cutting chart by fabric: strip width, how many strips, and how many pieces per strip at UsableWidth.
5. Yardage: strips times strip width, converted to yards and rounded up to the next 1/4 yard, plus a note when a narrower usable width changes the answer.
6. Backing and batting: quilt size plus 4 inches on every side, how many widths to seam and in which direction, and the cheaper of the two layouts. Binding: perimeter plus 12 inches at 2 1/2 inch strips.
7. Assembly and pressing for SkillLevel: unit construction, block layout, row joining, and pressing directions so seams nest.
8. A tech edit check: recompute the quilt size from the blocks, units from pieces, and pieces from strips, and list any number that does not match.
Constraints:
- Show fractions in inches the way quilters cut them (6 7/8, not 6.875). Show the arithmetic.
- Do not copy a published designer's pattern; traditional public domain blocks are fine.
- No shrinkage or fabric brand claims. No em dashes.