A new approach to determining the constructive balance for the design of customised patterns of men garments

Abstract

The objective of this study was to develop a new method of designing ergonomically shaped men’s jackets that perfectly adapt to the customer’s body shape and style (i.e. custom made jackets). The study included 10 adult subjects who prefer to wear formal jackets to work. These subjects underwent 3D scans, and the images were used to execute the study objective. The constructive balance values of men’s jacket patterns were determined by considering the characteristics of the subject’s torso and preferred style. The longitudinal contours of the torso were described by parabolic equations, which were solved with the Gauss method. The obtained value of the constructive balance (1.5 ÷ 3 cm) was used to design jackets using a particular module of Gemini CADs, which allows the mathematical relations between the positions of specific points on the contour of a men’s jacket to be expressed. The pieces are designed in Gemini’s geometric layer. The designer can establish the mathematical relations based on his/her pattern-making competencies and human body and garment evaluation results. In a 3D virtual environment (Lectra-Modaris 3D), the customer’s avatars were dressed with the same jacket model but with different bust lines and various widths on the lateral side. The bust line level was established by using the backside length (measured from the seven-vertebra until the armpit level) and an allowance value, which was established after the human body backside curvature, garment silhouette, number of layers, etc. were analysed. Two variants of the jacket model were designed: a regular- and a medium-fit at the bust level (the value of the constructive bust allowance was 7 ÷ 10 cm). The garment position on the body was evaluated by studying its relative displacement when the avatar performed regular movements (moving his upper limbs). Thirteen cases were considered significant and used to analyse the jacket hemline relative displacement (relative to its horizontal position). These cases were analysed with factorial programming and a rotatable compound central programme with two independent variables. The best shape, size and position of the jacket on the virtual body were determined for the following situation: the value of the backside allowance (longitudinal direction) was between 1.6 and 4 cm, and the width of the jacket on the lateral side was calculated with the percentage of the constructive bust allowance ranging from 49% to 51%. With these parameters, the garment appears to fit the body well.