Slavenka Petrak

Systematic Representation and Application of a 3D computer-Aided Garment Construction Method, Part I 3D garment basic cut construction on a virtual body model

Purpose – To establish a method of transforming the 3D cutting patterns constructed and modelled into 2D patterns, excluding the fabric parameters.Design/methodology/approach – Three methods have been developed for transforming 3D cutting part segments into 2D segments. They are based on the computer‐based application of the mathematical models developed. The mathematical models differ in their concepts and the application in a particular manner of transforming the 3D segments. Complex spatial matrix transformations have also been developed and used to further transform the 2D segments into the plane of chained 2D cutting pattern segments.Findings – Two‐dimensional cutting patterns have been defined for the 3D garment model, initially constructed on a computer‐generated body model.Research limitations/implications – The method has been developed on an example of a 3D garment basic cut construction of a single article of clothing. However, the same principles can be applied and developed for any garment ba...

Systematic representation and application of a 3D computer‐aided garment construction method: Part II: spatial transformation of 3D garment cut segments

Purpose – To establish a method of transforming the 3D cutting patterns constructed and modelled into 2D patterns, excluding the fabric parameters. Design/methodology/approach – Three methods have been developed for transforming 3D cutting part segments into 2D segments. They are based on the computer‐based application of the mathematical models developed. The mathematical models differ in their concepts and the application in a particular manner of transforming the 3D segments. Complex spatial matrix transformations have also been developed and used to further transform the 2D segments into the plane of chained 2D cutting pattern segments. Findings – Two‐dimensional cutting patterns have been defined for the 3D garment model, initially constructed on a computer‐generated body model. Research limitations/implications – The method has been developed on an example of a 3D garment basic cut construction of a single article of clothing. However, the same principles can be applied and developed for any garment basic cut. Practical implications – The mathematical models developed can be used in a new computer‐based application for the 3D garment construction and the development of the 2D cutting patterns, matched to individual physical characteristics. Originality/value – The most outstanding property of the method developed is the possibility of gradual transformation of 3D cuts into 2D ones, with no need to define physical‐mechanical properties of the fabric used and no need to introduce fabric drape. The newly created 2D cutting patterns are of outstanding quality and preciseness.

Methods of automatic computerised cutting pattern construction

The procedure of computerised automatic construction of a cutting pattern for men’s shirt is presented. It is based on the calculation of construction measures necessary for the calculation of all the construction elements. The procedure of construction is similar to the conventional hand procedure, but is done using a computer, so that the locations of the co‐ordinates of all the principal and auxiliary points on cutting part contours are calculated. Straight segments are drawn afterwards through these calculated points and curved segments interpolated.

Research of 3D Body Models Computer Adjustment Based on Anthropometric Data Determined by Laser 3D Scanner

The paper presents the investigation of the computer 3D body model adjustment possibilities for the implementation in the 3D CAD system for computer-aided design and garment simulation. In this context, three methods of connecting data on measurements and body shape found by using 3D body scanner and 2D/3D CAD system for computer- aided design and garment simulation were investigated. The first method refers to the research of the possibilities of interactive avatar adjustment in the CAD system based on the analysis of the anthropometric characteristics of the body and measurements found by using a 3D body scanner. The second method involves establishing a systematic record of body measurements found by using a 3D body scanner as the input record format in a 3D CAD system, which is used for automatic avatar adjustment. The third method involves creating a computer record of the body model using the program for 3D scanning, that is suitable for the direct implementation in the 3D CAD system for garment simulation.

Impact of Male Body Posture and Shape on Design and Garment Fit

This paper presents a study of the impact of body posture and the presence of functional and structural body changes on garment fit. 3D scanning on a sample of 50 male test sub jects was performed. Body posture indicators were determined on 3D body models and a statistical analysis of the results obtained was performed. Test subjects from the sample were divided into three groups according to body posture types. Three body models with different body dimensions and different physiological spine curvature were selected and im ported into a 2D/3D CAD system for computer-based garment simulation. 3D simulation of a men’s jacket in the closest garment size was performed on selected body models. Garment fit was analysed on every simulated model and based on the analysis performed, garment pattern elements and measurements where it is necessary to enable modifications were de termined. The most complex part of the research refers to the development of a parametric computer-based garment model which will be able to adjust according to anthropometric body measurements and body shapes with a different physiological spine curvature. Relationships between targeted body measurements and their impact on modifications of pattern segments were investigated as a starting point for defining mathematical expres sions according to which values of measurement changes on the garment pattern will be calculated. A parametric garment model pattern which enables adjustments according to different body sizes and body postures types was developed. Verification of the method developed was performed using computer-based 3D simulations on 3D body models with prominent problems of body posture.

The Volumetric Analysis of the Human Body as Starting Point for Clothing Pattern Design

The paper presents evaluation of the overall and microclimatic volume changes due to different upper limb positions simulating functional reaching movements for the aircrew personnel. The study was performed in order to evaluate the needed ease allowance added to chest and waist circumference for outerwear garments in order to fully achieve the wearing comfort. The accurate 3D body scanning was used and the impact of the upper limb position on microclimatic volume distribution was tested. The scanning data process was performed using a 3D laser scanner and a computer analysis. The raw scans were processed and reconstructed. After the scan reconstruction, the volume and the area were calculated. The experimental study covered the objective measuring methods: the material testing, the 3D scanning, the scan reverse engineering modelling and the volume/area calculation. The volume calculations included both the overall volume calculation for the unclothed torso and for the torso dressed in the chosen outerwear jacket. It also included the volume calculation of an air layer formed between second and third layered garments. The clothing ensemble CE 0 is the control variable, the unclothed body. The CE 1 is the clothing ensemble combined from the underlying basic garments (undershirt, underpants, classical male business shirt, and jeans) and combined with the bomber jacket. The three human subjects with the analogous body proportions (the height of 185 cm and chest girth of 100 cm) were scanned using the 3D laser body scanner Vitus Smart (Human Solutions GmbH) in an upright standing position according to ISO 20685:2010 changing only upper limb positions simulating functional reaching movements for the aircrew personnel.

Changes in Ensembles’ Thermal Insulation According to Garment’s Fit and Length Based on Athletic Figure

The purpose of this paper is to analyse the impact of design solutions on the thermal insulation of the garments and the ensembles. Previous studies investigated the microclimatic air gaps and volumes, however only under the first - and the second - layered clothing. Since none of the previous studies covered three - layered ensembles, in this study ensembles were accompanied by jackets of different fit and length to investigate the ensembles’ thermal insulation. Variants of bomber jacket differ in the amount of the ease allowance, while variants of the parka differ in length. The thermal insulation of the ensembles increased for 21.6 to 59.7 % when one of the jacket variants was added as the outerwear garment. A threshold volume, after which the thermal insulation will start to decrease due to convection, wasn’t determined for the outerwear third - layered garments nor was the impact of the length of the garment on the thermal insulation clearly stated. This study involved laboratory testing of garments and ensembles by 3D body scanning and thermal manikin measurements. To evaluate the volume of the microclimatic air volume the accurate 3D body scanning was used and the impact of the microclimatic volume on the ensemble’s insulation was tested. The thermal insulation for the selected outerwear garments and afterwards ensembles was measured by resting thermal manikin. Analysis of the results obtained from tests, showed that the garments’ fit and length can be used to model the overall thermal insulation of the ensembles. The ensembles insulation enlargement was measured for microclimatic volumes up to 33.57 dm3 (measured with ensembles accompanied with bomber jacket). The study proved that the limiting microclimatic volume is greater for three - layered clothing, than previously reported. The overall ensembles’ insulation increased simultaneously with the length enlargement (measured with ensembles accompanied with parka jacket). Findings will be of help in the future research on garments and ensembles thermal properties modelled through the design process and the construction.

A method for body posture classification of three- dimensional body models in the sagittal plane

The main purpose of this research was to develop a method for the classification of body posture types, using a three-dimensional body scanner and data on anthropometric measurement. A sample of 102 male test subjects, aged from 20 to 30 years, and without structural deformities of the locomotor system, were scanned. Anthropometric body measurement was performed and 16 measurements were selected to calculate upper and lower body curve angles as a set of posture indicators. The number of maximally different groups of test subjects was determined using k-means cluster analysis and factor analysis of established posture indicators. The sampling into three upper and three lower posture types showed the largest statistically significant differentiation, comparing the results of variance analysis between and within the obtained groups, which confirmed three main components extracted by factor analysis. Discriminant analysis used in order to determine differences between posture types showed which indicators are the most important when classifying test subjects belonging to a particular upper or lower posture type. Classification functions were defined based on discrimination functions and their factor loadings, and used to calculate a matrix of correctly classified test subjects. The classification matrix showed very high prediction possibility of established posture indicators and the proposed method for body posture classification.

Analysis of dynamics and fit of diving suits

Paper presents research on dynamical behaviour and fit analysis of customised diving suits. Diving suits models are developed using the 3D flattening method, which enables the construction of a garment model directly on the 3D computer body model and separation of discrete 3D surfaces as well as transformation into 2D cutting parts. 3D body scanning of male and female test subjects was performed with the purpose of body measurements analysis in static and dynamic postures and processed body models were used for construction and simulation of diving suits prototypes. All necessary parameters, for 3D simulation were applied on obtained cutting parts, as well as parameters values for mechanical properties of neoprene material. Developed computer diving suits prototypes were used for stretch analysis on areas relevant for body dimensional changes according to dynamic anthropometrics. Garment pressures against the body in static and dynamic conditions was also analysed. Garments patterns for which the computer prototype verification was conducted were used for real prototype production. Real prototypes were also used for stretch and pressure analysis in static and dynamic conditions. Based on the obtained results, correlation analysis between body changes in dynamic positions and dynamic stress, determined on computer and real prototypes, was performed.