Page 239 - Anthropometry, Apparel Sizing and Design

Evaluation of pattern block for fit testing 231

9.4.5 Ease calculation from pattern block

From horizontal and vertical cross-sections taken from the scanned system “body-
clothes” and consisting of two cross-sections of body and clothes, two types of ease
can be calculated: first, the ease as the difference between the lengths of two perim-
eters; second, the ease as the air gap located between both perimeters.
From the pattern block, the calculation of ease allowances isn’t a simple task. They
vary drastically with type and style of clothing, from knitted tight-fitting garments
with negative ease values to oversize garments with enormous ease values. For exam-
ple, if the length of shoulder line is presented as the sum of shoulder length (width)
taken from the body and the ease amount, this approach can be used only when the
shoulder line starts from SNP and finishes at SP exactly (Gill, 2015). But this situation
takes place only for a basic pattern block and this approach couldn’t be applied for a
shaped pattern block or for a historical pattern block.
For flat pattern blocks and RTW clothes, the eases E i for girth, width, length can be
found by this equation:

E i ¼ D BM: (9.5)

where D is the measured dimension of the pattern block or clothes in centimeters; BM
is the body measurement in centimeters.
For analyzing and parameterization of a pattern block by means of ease amounts,
the initial database for starting this process should include:

(1) drawing, photo, or sketch of garment;
(2) schedule of body measurements used for pattern block making;
(3) properties of textile materials (shell, lining, interlining) such as thickness, shrinkage after
heat-moisture treatment, elongation, and so on;
(4) thickness of underwear clothing.
To present the specific morphological features of the human body and key body mea-
surements, they can be transformed into a flat anthropometrical net. The
anthropometrical net is the fragment of the body surface that is oriented on the flat
surface and consists of key anthropometrical points in accordance with the body mea-
surements. This net is the morphological passport of the human body with known
sizes. Figs. 9.4 and 9.5 show the anthropometrical net and its application for calculat-
ing the ease amount from the pattern block. The algorithm of net building is based on
the triangle method.
An anthropometric net includes many anthropometric points: back neck point BNP,
shoulder neck point SNP, blade point BLP, shoulder point SP, bust point BP, front
neck point FNP, armpit back point APB, armpit front point APF. The anthropometric
levels are waist level WL and hip level HL. To draw the net, the body measurements
shown in Table 9.7 are needed.
All body measurements can be measured, calculated, or found out manually or by
means of a bodyscanner. Fig. 9.5 shows the location of the main eases obtained by
overlapping the anthropometric net and the pattern block. To find out the ease amount,