The authors use the direct measurement method to survey measured data. Subjects were 30–60-year-old male civil servants in Ho Chi Minh City. According to the laws of anthropometric development, this age range will be divided into two stages: the middle-aged stage and the adulthood stage (15). Therefore, there will be two age groups in the measured samples: the 30–45 years old and the 46–60 years old. In each group, 30 samples will be randomly measured and selected primary dimensions for height, weight, bust, waist, and hip girth, which leads to being able to choose the highest standard deviation dimension. The results of both groups are analyzed by the statistical method (16). It showed that weight had the highest standard deviation, followed by the waist dimension. The abdomen dimension will show the difference in body shapes clearer than those of weight. Because of this reason, abdomen girth is chosen as the primary dimension to calculate the number of measured samples for research purposes. As a result, groups 1 and group 2 have abdomen girths with a standard deviation of 7.53 cm for the former and 7.52 cm for the latter. The middle-aged participants were almost office workers in Ho Chi Minh City, so they had similar living conditions in terms of geography and had a notably stable height. One or more unified sets were grouped to process measured data and establish the sizing system table. The standard deviation of the abdomen girth is 7.53 cm. The number of samples to be measured is calculated according to formula (1):

where:

Substituting the parameters into the sample calculation formula (1) will have the number of samples to be measured from 378 men. The 3D Size Stream body scanner is used to scan the full size of a person’s body (17). Its 3D scanning consequences are extracted into PDF and Excel files that are used for data analysis on the SPSS software.

American Size Stream 3D body scanner is a machine with a 3D scanning system designed to capture three dimensions of the entire person’s body, including 14 infrared sensors, placed at different heights. Sensors connected via UBS ports to a computer control the scanner and load data (Figure 1).

The sample measurement procedure is as follows:

Ao dai fabric is made up of cotton sateen, with a weight of 137.8792 g/m² and a thickness of 0.32 mm (Figure 2).

Men’s Ao dai sketch image is shown in Figure 3.

The cross-sectional statistical method is used in a survey of 378 databases on men from 30 to 60 years old living in HCMC. Moreover, the K-mean cluster method is used to provide body shape grouping options. The 2D pattern design method is used to design pieces of the men’s Ao dai in the Gerber software, while the sample draping 3D method uses the flat patterns transfer to the avatar.

The results of the analysis of anthropometric dimensions of 378 men aged 30–60 years living in the southern region of Vietnam are presented in Table 1. Values such as standard deviation, mean, maximum value, minimum value, and range of variation are statistical and used in the process of classifying the human body shape. There are a total of 45 measured dimensions.

The avatar in the study is made according to the average measurements of Table 1. Combined with the results of avatar construction in the study (18), a 3D model has been created to simulate shape and structure as shown in Figure 4.

The men’s Ao Dai is designed by the 2D method on the Gerber software with patterns as shown in Figure 5. The measurements are used to design patterns that have medium measurements in Table 1.

Figure 6 is a sample image of a shirt surface simulation on the CLO3D software with avatars built by anthropometric scan datasets of 378 middle-aged men in Ho Chi Minh City.

Testing and assessing the fit of samples in the CLO3D software are determined by Strain Map color distribution maps. Each color will describe the state of the product. The color of the graph represents the contact position of the garment with the wide to the tight body surface. As can be seen, fit positions are blue, and easy locations are white. Figure 7 shows that there are wrinkles in the back waist and side. The neck and armhole area reaches the fit of Ao dai. Thereby, the authors give the direction of adjustment in the front and back body according to the straight form of the body, chest across, waist across, and hip across (Figures 8–10). Other locations keep the same design.

The images of patterns after adjusting describe the smooth and flat, not wrinkles, and it fits the avatar (Figure 11). A comparison from the color chart shows that the front body, back body, and sides are fit, with no wrinkles in the waist area (Figure 12).

The dimensions of samples built in the study were compared with the male measurements in the TCVN 2009 table, showing that the primary dimension in this study was larger than that standard. The height is 154.46–181.35 cm, while the standard is from 150 to 179 cm. The bust dimension of the incline is 85.62–114.01 cm, while that in the standard is from 74 to 95 cm. Although the abdomen girth is 73.65–103.77 cm, the standard is 64–85 cm. Similarly, the hip girth is also larger with 84.51–111.81 cm in the study and 80–97 cm in the standard. Thereby, the body dimensions of Vietnamese men from 30 to 60 years old are now taller than that in the standard table 5782:2009. As for the avatar dimensions, the height of 167.88 ± 5.35 cm belongs to the standard measurement range, and the avatar’s bust, waist, and hip girth are larger than the standard measurement range. The original pattern details have a tight waist girth and a wrinkled back waist, but the neck girth and armhole fit the avatar. After adjustment, the patterns of the Ao dai front and back body are not tied at the waist, and the images of the simulation of men Ao dai are flat, with no wrinkles.