Validating women's bilateral body asymmetry thresholds for patternmaking based on 3D body scan data

Purpose The purpose of this study was to analyze the prevalence of bilateral body asymmetries among women using the Size USA database and to examine how age, body mass index (BMI) and ethnicity influenced these asymmetries in upper and lower body measurements. Additionally, the study evaluated the reliability of the asymmetry thresholds suggested in the Joseph–Armstrong patternmaking method. By exploring these factors, the research aimed to provide valuable insights for improving garment fit and patternmaking practices to better accommodate diverse body shapes and characteristics. Design/methodology/approach The Size USA database was used to analyze bilateral body asymmetries among women's body measurements and the associations among body measurements with age, race and BMI in patternmaking and clothing fit. Findings This study validated the need for drafting an asymmetric pattern when the difference between the left and right sides of the body at the shoulder slope exceeds 1/8 inch. Additionally, how body asymmetry should be accommodated when drafting flat patterns was examined using a bodice example. The asymmetrical garment, drafted based on the shorter shoulder slope measurements, provided the best fit. Originality/value Patternmakers develop patterns based on the right side of the body, assuming the other side would have exact mirror symmetry. However, the human body is not perfectly symmetrical. Even though there are recommendations that patterns should be altered to improve the fit if body measurements vary considerably between the left and right sides, only a few guidelines exist about asymmetrical variations. Study findings implied that when significant differences in body measurements, such as shoulder slope, are present, asymmetries should be accounted for in patternmaking to ensure better fit.