Page 248 - Anthropometry, Apparel Sizing and Design

240 Anthropometry, Apparel Sizing and Design

E BL ¼ T tm:b1 М BNP М WL : (9.10)

where /11-41/ is the length of the back line from highest point 11 to point 41 located on
the structural waist line (Fig. 9.8B), cm; BL is the body measurement “back length,”
cm; E BL is ease allowance to back length that consists of three components, cm: T tм.b1
is the ease allowance that equals to the textile material thickness, cm; М BNP is the ver-
tical distance between BNP and point 11, cm; М WL is the vertical distance between the
natural waistline WL and the narrowest structural level of the clothes /41-471/, cm.
М BNP can have different values depending on style: for a basic pattern block with
closed neckline М BNP 0; for clothes with a collar М BNP ¼ 0.3cm; for raglan and
dolman styles М BNP ¼0.5–0.8cm. М WL depends on the silhouette and may be positive
(as 1920s style) and negative (as an empire style of the beginning of the 18th century).
So, the total amount of б lu may be positive or negative.
Longitudinal arc balance includes front-back б lfb and side б ls indicators.
Longitudinal front-back balance б lfb shows the position of points 42 and 46 on the
structural waist level /41-471/; б lfb is equal to half of the difference between the sim-
ilar dimensions belonging to body and clothes:

б lfb ¼ 0:5 =121-42= + =16-36-46=ð½ Þ FL SNP BL SNP Þފ: (9.11)
ð
The equation for calculation of б lfb is:

б lfb ¼ 0:5 T tм:f 2 + T tм:b2 + T tm:sp + E bending М WL : (9.12)
where T tм.f2 and T tм.b2 are the ease allowance, which equals the textile material thick-
ness of front and back, respectively, cm; T tm.sp is the ease allowance that equals the
thickness of the shoulder seams, cm;E bending is the ease allowance appearing as an
additional value due to the bending of clothes under the shoulder area, cm.
Eq. (9.12) can be simplified by using the average thickness T tm.av of textile mate-
rials instead of the two values T tm.f2 and T tm.b2 :

(9.13)
T tm:av ¼ 0:5 T tm:f2 + T tm:b2

б lfb ¼ T tm:av М WL Þ +0:5 E bending + T tm:sp : (9.14)
ð
1st balance concordance between б li and б lfb is

Δ 1 ¼ б lfb -б li ¼ 1 1:1ð Þ T tm:av : (9.15)

For example, for one-layer clothes made of thin fabrics, when T tm.f2 ¼ T tm.b2 and
М BNP ¼0, 1st balance concordance will be:

б lfb ¼ б li : (9.16)