## New Dressmaking Dummy Based on the Average Form of Young Adult Females

A dressmaking dummy is not a manikin to display dresses. The dummy is a tool to make clothes patterns through draping. Therefore, its bust, waist and hip conform with the dimensions standardized in JIS, and its form is close to that of the human torso. In traditional dressmaking dummies, however, the cross-section shapes of bust, waist and hip, as well as the form between these cross sections are made manually according to experience and artistic sense. Thus, its overall form is different from that of the actual human body.

In a collaboration study with Bunka Fashion College, we developed a new dressmaking dummy based on the average dimensions of actual human body forms. The bust, waist and hip dimensions are identical with the average dimensions, and so, its form represents the average body form of young adult females today. To calculate the average form, the technology developed by Digital Human Research Center was used.

The differences in form between the new dummy (left) and a traditional dummy (right) are clearly observed in Figure 1.

## Development of the new dummy

The new dummy was developed according to the following procedure.

### Measurement

Subjects were young adult females wearing clothes of size 9AR, from the Japanese Industrial Standard for the size of women's clothes, and with a "beautiful body". "Beautiful body" here means well balanced and with neither negligible body asymmetry nor sclerosis. The surface data was measured with a voxelan (Hamano Engineering co.), a 3D body scanner. Body dimensions were also measured.

### Modeling

The raw, 3D scanned data has a different number of data points for each subject. In order for all subjects to have the same number of data points, and also for each data point to have the same anatomical meaning on each subject, a digital model of the surface shape of each subject was created by reconstruction of data points. In the torso form analysis to design the dressmaking dummy, the digital model consisting of 500 data points as shown in Figure 2 was created by using anatomical landmarks and cross-sections.

### Average Form

The average form was calculated using the shape transformation technique developed by us. The resultant average form represents the characteristics of the present-day young adult females, but it does not have characteristics of any particular individuals.

Free Form Deformation (FFD) technique is one of techniques in computer graphics, and developed by professor Sederberg of Brigham Young University. In the original FFD technique, control lattice points are defined around a 3D object (Figure 3, left). By moving the control lattice points, the 3D object is smoothly deformed (Figure 3, right).

We think the deformed grid rather than deformed object more interesting. It is because the deformed grid is a function representing the differences between the 2 forms. If the original form and the target form are digital models of the human body, and if the digital model consists of the same number of data points of the same topology, then we can calculate the movement of the control points that deforms the original form into the target form.

Figure 4 shows an example of the foot deformation. A digital model consisting of 174 data points, each of which is defined based on the anatomical correspondence, was made for each foot. If the 2 forms are similar, only small movement is enough to deform the original form into the target form. If the 2 forms are different, large movement is necessary to deform the original form into the target form. Therefore, we can define a morphological distance as the sum of movements of all the control points.

Since the deformed grid carrys the information on the differences between the 2 forms, it is possible to apply the deformed grid to designing product forms. Supppose there is a "standard" body form (upper left in Figure 5), the product that fit to the "standard" body form (lower left in Figure 5), and a "non standard" body form (upper right), and there is no product that fit to "non standard" body form. First, calculate the deformed grid that deforms the "standard" body shape into the "non-standard" body shape. By deforming the product shape that fit to the "standard" body shape using the deformed grid, we can obtain a product shape that fit to the "non-standard" body shape.

### Detailed average form

The average form calculated in step 3 consists of only about 500 data points and is too rough to make a dressmaking dummy. The detailed average form was calculated as follows. First, the median form is selected. The median form is defined as the form with the smallest standard deviation of the morphological distances when compared to other subjects. Since the median form is a real subject, detailed surface data is available. Next, the transformation grid that deforms the median form into the average form is calculated. Finally, by deforming the detailed median form data using the transformation grid, a detailed average form is obtained as shown in Figure 6.

### Materialization of the average form

The resultant detailed average form was materialized by rapid prototyping, and the materialized average form was modified manually. The modifications were mainly for filling the unnecessary gaps or hollows such as navel.

### Production of the new dressmaking dummy

Thus the resultant modified detailed average form was used as the pattern for production of the new dressmaking dummy.

## Evaluation of the new dummy

The new dummy was evaluated on two points: 1) If it really represents the characteristics of the body forms of young adult females, and 2) if it is useful for making accurate clothes patterns to fit today's young adult females.

For point 1, two angles were measured from silhouette photographs (Figure 7) of the new dressmaking dummy. The angles measured for 452 young adult females were compared. As shown in Figure 7, the measurements of the new dummy are very close to the means for the 452 subjects. However, the angles of a traditional dummy are greater than the means for the living subjects.

For point 2, the original pattern of Bunka Fashion College was tried on each of 231 young adult females, with bust sizes of 80, 83, 86, or 89 cm, and was modified to fit each subject. Based on these modifications, the original pattern was modified to make a new pattern. This new pattern was tried on the new dummy, and it fit very well. Figure 8 shows the new pattern on the new dummy (left) and on an existing dummy (right). The waist line is horizontal for the new dummy but sags for the existing dummy.

## A quarter size dressing dummy

Since a digital model can be easily enlarged or reduced, Bunka Fashion College has also developed a quarter-sized dummy (Figure). These dummies are used in the classroom, and students design patterns in their notebooks at a fourth of the normal size. They then cut out the patterns and fit them on a quarter-sized dummy.

## Other dummies

The completed dressmaking dummy is of size JIS9AR (Japanese Industrial Standard for women's clothes, size 9). Using the same technology, dressmaking dummies for young adult males (collaboration study with Bunka Fashion College) and for middle-aged females (collaboration study with Bunka Fashion College and Nissen Co., Ltd.) have been also developed in 2004 and in 2008, respectively.

## References

- Mochimaru, M., 2001: Development of a dressmaking dummy based on the digital human. Journal of the Japan Research Association for Textile End-uses, 42:26-30. (In Japanese)
- Kouchi, M., M. Mochimaru, and Y. Ito, 2001: Development of a new dressmaking dummy based on a 3D human model. Proceedings of Numeization 3D Scanning 2001.
- Kouchi, M., 2001: Development of a dressmaking dummy. Digital-Cyber-Real, pp.270-280. Maruzen. (In Japanese)

## Companies related to the development

- Bunka Fashion College: Measurement, modeling, manual modification of the materialized detailed average form
- Digital Human Research Center: Calculation of the average model and detailed average form.
- JMC: Materialization of the average form by rapid prototyping
- Nanasai: Production of the dressmaking dummy
- Nobon Japan: Material for the dummy

The new dummy can be purchased from Bunka Fashion College.