Overview / Goal

Demonstrate how to transform a large waterproof mattress protector (180×200 cm) into 70+ reusable underwear pieces.

• Remove the elastic skirt completely and set it aside for other sewing projects.

• Begin with a clean, flat waterproof sheet.

Sizing & Marking Setup

• Identify the plastic waterproof side — always draw patterns on this side.

• Confirm underwear sizes in advance (e.g., size 4 large, size 3 medium).

• Never mix sizes in the same row to maximize space along the mattress protector.

• Before cutting, clearly label each traced piece with its size number (4, 3, or 2).

Smart Pattern Placement

• Place patterns efficiently in one direction, then flip alternating pieces like a mirror.

• Fit curves into curves to eliminate wasted gaps.

• If the final large pattern does not fit at the end of a row, use leftover space for a smaller size (e.g., size 2).

Cutting (“dance” method)

• Avoid tight cutting around curves to prevent wrist strain and fabric damage.

• Cut slightly beyond each curve, allow the fabric to release and flip, then re-enter from an easier angle.

• This method maintains accuracy and body safety.

• If possible, use a table for better posture; the floor is still acceptable.

• Cut full rows first before separating individual pieces.