Pattern Piece Nesting Optimizer

This tool uses a Bottom-Left Fill algorithm — the same family of algorithms used by industrial nesting software. It sorts your pieces by size, then places each one in the lowest, leftmost position where it fits without overlapping any already-placed piece.

The result is typically 80-90% efficient for standard sewing patterns, compared to 60-70% efficiency from manual layout. On a project using 3 yards of $20/yard fabric, that's $6-12 saved.

The height of each piece is the dimension that runs along the grainline (parallel to the selvage). The optimizer never rotates pieces 90° — the grainline must always run along the fabric length. For non-directional fabrics, pieces can be flipped 180° to fit better.

If your fabric has a nap or directional print, check the "Directional fabric" box. This prevents piece flipping, which may use slightly more fabric but ensures all pieces face the same direction.

Pieces marked "on fold" are placed at the fold edge of the fabric (shown as a dashed green line on the left of the diagram). These pieces are constrained to x=0 in the layout, which means they can't be nested as freely as other pieces — but they're necessary for symmetrical pieces like center front and center back.

Enter the half-width of on-fold pieces (as printed on the pattern). The piece will occupy that width from the fold edge.

This optimizer uses rectangular bounding boxes— it doesn't account for the actual curved shape of pattern pieces. Real pieces can often nest more tightly (e.g., a sleeve and a skirt front may interlock at the curves). The optimizer gives a guaranteed upper bound on fabric needed, but you may be able to do slightly better by hand for pieces with compatible curves.

For very large projects (20+ pieces), the layout may take a moment to compute. The algorithm is fast for typical garment projects (5-15 pieces).