The science of stretch-knit pattern construction: establishing ease distribution in a digital prototyping environment

Purpose Stretch knit garments are popular for their adaptability to diverse lifestyles, yet their expected fit is ambiguous because stretch reduction and ease are frequently confused. The conceptual basis and systematic application of ease in stretch-knit pattern drafting, therefore, remain insufficiently articulated in the existing literature. Accordingly, this study aims to establish a theoretical foundation for ease in women’s upper-body stretch-knit pattern drafting. Design/methodology/approach The study used an experimental design in which three well-established women’s upper-body stretch-knit pattern drafting methods were critically analysed. Parametric patterns were developed using 2D CAD, and digital prototypes were created using 3D CAD, for a UK size 12 AlvaForm. Negative ease values applied were quantified and evaluated using digital fit assessment results utilising eight quasi-static poses. Findings The key findings demonstrate that garment misfit is not a random occurrence but an inherent structural outcome arising from oversimplified ease estimation rules in current pattern drafting. Also, the results indicate that the negative ease requirement is a function of body measurements, fabric stretch properties and body poses, rather than a fixed numerical constant. Research limitations/implications The study advances digital garment production and the development of contour garments using stretch knit fabrics by providing a theoretical decoding that contributes to the evolution of parametric pattern drafting, offering valuable implications for both academic research and industry applications. Originality/value This research established the logic of negative ease values applied in stretch-knit pattern drafting, providing a theoretical decoding to support pattern development beyond empirical practices.