## 2 Materials and Methods
### Sizing System Development
#### 2.3.1 Segmenting the Size Section  
To obtain sample data, 2D human body measurement data of 199 Korean adult males provided by the human body measurement database of the sixth Size-Korea project (2010) were used. To select the important variables of height, hip circumference, and lower-drop, the body-size variables defining the standard body shapes of adult males were selected. Height is an important variable associated with body size; hip circumference is an important variable associated with volume, and lower-drop (the difference between the hip circumstance and the waist circumstance (omphalion)) is an important variable associated with physical features. To segment the important variables into sections, they were evenly divided into 10 section along a range of minimum-maximum values, 10 size sections were generated as shown in Table 4, and the normal distribution of 10 equally divided sections was confirmed through frequency analysis of the size sections for each important variable. In the primary cross-tabulation analysis, the dimensions of the important height and hip circumference variable are coded on a nominal scale of 10 sections using the SPSS statistics analysis program, and then cross-tabulation analysis is performed to determine the distribution of the size section between the height and hip circumference important variables. The calculation results of primary cross-tabulation are shown in Table 5. The chi-square value was 71.465 and the \(p\)-value was 0.049. Since \(p<0.05\), it was confirmed that the difference between groups was statistically significant. As for height, section 6 showed the highest frequency with 23.6%. As for hip circumference, section 5 showed the highest frequency with 23.6%. \begin{table}
\begin{tabular}{c c} \hline \hline
**Step** & **Content** \\ \hline
1. Obtaining sample data & 2D human body measurement data are used. \\
2. Selecting important variables & Three body measurements for body shape classification are selected as the important variables. \\ \hline
3. Segmenting important variables into section & Important variables are segmented into section through a descriptive statistical analysis. \\ \hline
4. Primary cross-tabulation analysis & Primary size sections are generated based on the important variables 1 and 2. \\ \hline
5. Secondary cross-tabulation analysis & Final size sections are generated by applying the important variable 3 to the primary size sections. \\ \hline
6. Forming the representative grid & Representative grid for each section is formed after generating the sample data into a 3D scatterplot. \\ \hline
7. Generating size of important variables for each representative grid & Mean value of each important variable of the sample data included in each representative grid is calculated. \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Size-section segmentation process. \begin{table}
\begin{tabular}{c c} \hline \hline
**Step** & **Content** \\ \hline
1. Obtain sample models & 3D human body shape model data are used. \\ \hline
2. Classify sample models & Sample models are classified based on the range of the section by the representative grid. \\ \hline
3. Select template model & One template model is selected in the range of important variables \(\pm\)10 mm for each representative grid. \\ \hline
4. Select sample model & Based on the similarity to the template model, five sample models are selected for each representative grid. \\ \hline
5. Body-section analysis & Body sections, including the body cross-sections, longitudinal-sections, and side seams of the five sample models, are extracted for each representative model. \\ \hline
6. Generate average wireframe & Average body sections are generated by averaging each extracted section. \\ \hline \hline
7. Body cross-section modeling & An average wireframe is generated based on the average body sections. \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Average model generation process. The process of section removal and grouping in primary cross-tabulation analysis was as follows.