19

PART ONE: FABRIC ESTIMATION FOR PATTERN CUTTING

2 A categorisation for designers and pattern cutters

Measuring fabric characteristics 20

The fabric characteristic scale for pattern cutting 22
Weight 23
Thickness 24
Shear 25
Drape 26
Stretch 27
Fabric properties and 3D CAD images 28

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Measuring fabric characteristics

The background the ability in students in a variety of disciplines to
‘estimate’, the ability of visual estimation is one that
Designers should be aware that a major consideration in clothing designers cannot afford to lose. The techniques in
any design decision is the ‘fitness for purpose’. In particular this book may help designers to strengthen their intuitive
sectors of industry, other considerations may override the sense of integrating form and fabric. To illustrate this point
‘ideal’ design decisions; for example, cost or availability of the photographs opposite show that a very simple circular
fabric. In sportswear, absorbency and perspiration control shape in basic fabrics (rayon jersey, light–medium-weight
are principal property requirements. It is important that a calico, heavy cotton twill) behaves quite differently when
designer discovers the type of relevant tests that are cut at different lengths and scales. Overlapping shapes at
required for a product’s viability (see Appendix Four). different angles in fabrics of complicated and uneven
However, this book is concerned with those characteristics structures provide problems of infinite complexity that
of a garment which affect its visual form. require refinements embedded within the process of
The visual appearance of any garment is directly affected cutting, it is not simply a procedure of prediction and
by the characteristics of the fabric in which it is made. modification. The photographs also demonstrate the false
Selecting the correct material for a design is a difficult images that can be created by working in quarter or
problem for a designer when an artefact is made from half-scale.
materials that are solid, rigid and stable, but the problems Five requirements: WEIGHT, THICKNESS, SHEAR,
are immense for garment designers working with the DRAPE, STRETCH for the initial selection of pattern
infinite variety of shapes and fabrics used in the textile cutting methods have been recognised in this book as
industry. Mathematics, textile chemistry, physics, crucial. This does not dismiss aesthetic qualities that impact
mechanics, structural engineering and other fields of on the senses; for example, colour, subtle textures and
science have been used in order to create theories that could tactile experiences or fashion and cultural influences. But
be applied. Journals are prolific with papers showing these, with the practical considerations of product type and
graphs and calculations to support methods of analysis, and ‘fit for purpose’, are different elements of the design
expensive equipment has been devised to measure the process.
properties of fabrics. Many large textile and garment
producers use these tests (see Appendix Four) especially
when comparing similar fabrics for their advantages for a Weight, thickness, shear, drape, stretch
particular product range. The relationship of these five characteristics to pattern
Some computer programs use these theories in their shapes will be discussed in detail in the pattern cutting
attempts to create realistic three dimensional (3D) models sections. Some simple examples may illustrate the changes
of fabric. The aim is to realise a virtual image of a garment to the types of garments worn today and how their cut will
during the pattern cutting process (see page 28). However, be principally determined by the fabric.
as discussed on page nine, the selection of a fabric by a There is a limit to the amount of heavy cloth (WEIGHT)
designer usually comes at a much earlier stage in the anyone wishes to carry on their body. Historically, heavy
creation of a range. Computer programs at this stage are cloth was associated with warmth; but lighter cloths,
more useful for decisions such as colour and pattern. wadded fabric (THICK), knitted pile (THICK AND HIGH
Determining the suitability of a fabric for the shape of a STRETCH) or windproofed bonded fabrics (THIN AND
design at the concept stage will still rely on human LOW STRETCH), have replaced many heavy woollen cloths.
discrimination. Each of these latter fabrics are likely to require different
stylistic and practical pattern cutting methods.
Fabric characteristics: Fabrics that allow distortion of the warp and weft
a practical categorisation threads (SHEAR) usually have good draping qualities, but
they will cause problems if they do not recover their shape,
There are enormous problems in defining and measuring particularly as they come under body strains. But many
some fabric characteristics, this does not mean that it new fabrics made from micro-fibres have HIGH SHEAR
should not be attempted. However, the methods of and also high recovery.
assessment described in the book are used solely for the Fabrics with little drape or stretch have to have any body
purpose of pattern cutting, they are done to give a ‘sense of shape achieved through cut, whilst a small amount of
visual and tactile order’. Flat pattern cutting is successful elastane (HIGH STRETCH) in a fabric can give a garment
when a designer’s intuitive knowledge of a fabric can some internal shape in wear.
generate a 3D mental image of the fabric shape that will be These are simple illustrations, but many decisions are in
produced by the flat pattern. Industrial pattern cutting has ‘grey areas’ where defining the limits are not easy. The
to be done with speed and this human mental facility is pattern cutting section will develop basic and more complex
faster than any computer system, it can be instantaneous. It shapes and illustrate how fabrics with particular
has been noted that the reliance on calculators has reduced characteristics are likely to behave in those forms.

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Figure 6 Three different fabrics cut in circular shapes of varying lengths and scales.

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The fabric characteristic scale for pattern cutting

The term ‘characteristic’ is used because it is a descriptive fabrics. Low numbers represent light, thin, high-shear, high-
term. In many textile books the words ‘characteristic’ and drape and high-stretch. Fabrics are quite likely to have a
‘property’ are used as if they can be interchanged. The mixture of characteristics. The fabrics used in the illustrated
latter should be used to relate to a fundamental chemical or garments are coded in the following way, for example:
biological property and in the context of broad design and
garment shape decisions, the term characteristic is far more Fabrics used in the illustration
useful. We Th Sh Dr St
The pattern cutting method or block chosen for the 1 Cotton voile 1 1 1 3 4
development of a style should start with an analysis of the
fabric. When the selection of fabrics was limited and style This means that the sample fabric is light-weight, thin,
conventions influenced design, methods of cut were high-shear, medium-drape and medium–low stretch.
predictable. The increased availability of very different
fabric ranges during the last decade needed a new The measurements recorded in this book were taken using
approach. The five principal fabric characteristics which simple but specially devised equipment (see Appendix
should be assessed before deciding the method of pattern Three). However, even simpler methods of achieving a
cutting or the choice of pattern block are: WEIGHT, similar result are shown on the following pages. Any
THICKNESS, SHEAR, DRAPE, STRETCH. They are student could take fabric measurements by these methods.
assessed across a five point scale 1 2 3 4 5. If students begin to assess fabrics in this manner, in quite a
short time they should be able to intuitively code a fabric
Opposite ends of each characteristic are as follows: for comparison quite quickly. This helps the process of
visualising a fabric’s capability to produce certain shapes,
WEIGHT Light-weight 1...5 Heavy-weight
and therefore compare and select fabrics.
THICKNESS (visual) Thin 1...5 Thick
Because the fabrics were so diverse (the scale would have
SHEAR High-shear 1...5 Low-shear
been distorted if any statistical procedure had been
DRAPE (visual) High-drape 1...5 Low-drape
imposed) the divisions between the categories 1–5 have had
STRETCH High-stretch 1...5 Low-stretch
to be taken across an even spread across the majority of the
fabrics. Extremely thick fabrics were not allowed to distort
Note that two are judged as a visual characteristic and
the group.
therefore could be termed a ‘visual measurement’. These
It is possible for others to disagree with my divisions and
terms are explained in the next section.
devise their own. This is not a mathematical scheme to be
It is not argued that this method should replace or
imposed, but a method that could be used across the whole
compete with other forms of technological measurement;
range of fabrics, or adapted for a particular fabric group.
instead, it is a different way of approaching the problems of
Within narrow fabric groupings, the use of a statistical
translating 3D forms from 2D pattern templates.
method (centiles) could be practical, agreement of the
Whilst it is recognised that other characteristics will play
category divisions could then be made.
some part and would give subtle variations to the stark
Throughout the book, there are no rules that dictate
divisions offered, STRENGTH, SMOOTHNESS (friction),
which fabrics should be used for particular blocks or
and COMPRESSION are secondary considerations. The
pattern shapes, but visual examples are given which
weave structure (open or closed) should be examined. Open
demonstrate what is likely to happen when they are
weave fabrics are often associated with shear, but many of
realised in fabrics with different characteristics.
the very closely woven micro-fibre fabrics can have shear
characteristics.
Special note 1. The 20 cm sample piece of woven fabric
should be cut accurately along the warp and weft threads,
The five-point fabric scale and along the wales of knitted fabrics. The fabric piece
The most accurate way of assessing fabrics is to use a full should be checked to determine that it is perfectly square
size circle of cloth, see page 21. However, the analysis in before the tests are carried out.
this book is made using only the fabric swatch piece (most Special note 2. The order of the fabric characteristics is set
fabric swatch pieces are on cards approx. A4 in size). This for appreciation for pattern cutting. However, if only one 20
means that a square of 20 cm can be cut from the swatch. cm square fabric sample is available, the least distortion to
The sample swatch may be all that is available to a designer the fabric will occur if the tests are made in the following
before purchasing a sample length. order: drape, thickness, weight, shear, stretch.
Each fabric illustrated in the book will have a reference Special note 3. The scale is a comparison across all fabrics
number attached for each characteristic. High numbers and is not a comparison within a particular fabric group
represent heavy, thick, low-shear, low-drape and low-stretch (e.g. shirtings).

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Weight
The weight of a fabric is important, large amounts of heavy type of broad categorisation that students may wish to
fabric can be uncomfortable to wear, but weight in a fabric undertake for themselves when calculating from a 20 cm
will help to make graceful vertical folds and will ‘swing’ square of fabric. Very accurate scales are required for more
dramatically. There has been a general movement to lighter rigorous tests (example: British Standards). These scales are
weight cloths, but some manufacturers are finding some usually available in university textile departments.
resistance where customers attach weight to fabric quality,
especially in wool fabrics. Often it is the reverse. Lighter wool
fabrics are often made from higher-grade fibres or yarns and Method for student practice
can be more difficult to weave. Light fabrics with low-drape If the weight is not listed on the fabric swatch, weigh a
and low-shear (example: cotton organdy) often give sharp 20 cm square piece of fabric (Fig. 7), then multiply the
crisp outlines but often crumple in use. This feature has been weight by 25 to calculate weight per square metre.
enhanced by many of the crinkle finishes available. Light The categories shown below were decided by judging
fabrics with high levels of drape and stretch (example: single that any fabric over 450 gm should be described as ‘heavy’,
jersey) give wonderful body fitting and drape lines. Compact, and then five divisions were created.
closely woven medium-weight fabrics with high-drape and
medium–high shear are excellent for crossway cutting The weight characteristic scale (in grams)
(example: crepes or some micro-fibre fabrics).
Weight information is usually recorded by the square 1 2 3 4 5
metre and to the nearest gm, although some fabric ranges Light Light– Medium Medium– Heavy
give 5 gm intervals. In most cases, the weight will be listed medium heavy
on the fabric swatch or is available from the manufacturer. 0–79.9 80–179.9 180–299.9 300–449.9 450+
European manufacturers generally list the weight per
running metre. To convert grams per metre length to grams
per metre square: divide the weight by the fabric width and Equipment used for weighing the fabrics recorded
multiply by 100. Some UK manufacturers may still show in this book
the weight in ounces. To convert oz weight to gm weight: The fabrics used and recorded in the book were weighed
multiply the oz weight by 33.91. (20 cm square) on an accurate TANITA Cal-Q-Scale which
Some domestic scales (see the photograph below) will calculated to 0.1 gm. See Appendix Three, page 212.
measure in 1 gm intervals, this would be adequate for the

Figure 7 Measuring weight. A method suitable for student practice. A 20 cm square of fabric measured on a domestic scale
that records in 1 gm intervals.

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Thickness
Fabric thickness is so variable that each fabric has to Method for student practice
be judged individually. Fabrics that appear thick can Place the 20 cm square of fabric between two blocks (Fig. 8).
be highly compressible, other fabrics have uneven Use a linen tester (a magnifying glass marked in
thickness that may be unevenly distributed. Very close millimetres and used in thread counting) to determine the
fitting garments will require extra ease allowances thickness of the cloth. Linen testers are available from
unless the fabric has stretch and recovery qualities. Most MORPLAN, a major supplier to the clothing trade.
thick garments are adapted from the easy fitting blocks. The categories shown below were decided by judging
Particular pattern cutting techniques have to be used that any fabric over 5 mm thick should be described as
where there is gathered or pleated fullness to reduce ‘thick’, and then five divisions were created. For illustrations
the bulk. Thick fabrics with low-drape and low-shear of a wider range of fabrics see Appendix Three, page 212.
characteristics can give exaggerated and stable geometric
outlines. Extravagant but soft shapes can be achieved The thickness characteristic scale (in mm)
with fabrics that are thick and have high-drape
qualities. 1 2 3 4 5
Fabric thickness is extremely difficult to measure. Thin Light– Medium Medium–thick Thick
Technical laboratories measure it under pressure, medium
it is recorded with a ‘load’ reference which flattens 0–0.4 0.5–0.9 1–2.4 2.5–4.9 5+
the fabric. This is useful for the making up of fabrics;
but for pattern cutting a visual measurement which Equipment used for measuring the thickness of
does not distort the fabric is more useful. When fabrics recorded in this book
comparing fabrics that are very textured or are The fabrics used in the book were hung vertically and
unevenly woven or knitted, a measurement can record scanned on an A4 SHARP flat-bed scanner. See Appendix
the thinnest and thickest points and take an average Three, page 212.
measurement.

Figure 8 Measuring thickness. A method suitable for student practice. A 20 cm square of fabric placed between blocks and
measured with a magnifying glass marked in mm.

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Shear
The amount the fabric shears (distorts in the warp and Percentages
weft; see diagram) can be measured. Shear can be an The percentage shear can be calculated by the following
advantage or disadvantage and the amount is important. equation.
The amount of recovery after strain is important. Closely
amount sheared 2 cm
woven fabrics with a high-shear characteristic (for example, × 100 e.g. × 100 = 10%
micro-fibre silk-like fabrics or some crepe weave fabrics) are original length 20 cm
very stable when used in crossway cutting. Open-weave
high-shear fabrics distort if under strain. Many complicated Equipment used for measuring the fabric shear
luxury fabrics, particularly fabrics in linen, silk and viscose recorded in this book
have this characteristic. Fabrics will tailor more A special piece of equipment was constructed that held the
satisfactorily if there is some shear quality, it allows the fabric under tension between two bars. A photograph of it
tailor to shape the garment; however, too much shear in use is shown in Appendix Three, page 213.
becomes a problem.

Method for student practice

Create a card scale for measuring shear and stretch. Draw a
horizontal line at the bottom of the card. Draw two lines at
right angles to this line 16 cm apart. Mark the right vertical
line and horizontal line in 0.5 cm intervals for 10 cm as
shown opposite. Draw a third vertical line at the end of the
scale.
Tape the 20 cm square of fabric onto the underside of two
rulers using 2 cm of cloth on each ruler. Place the first ruler
firmly at the left-hand start of the scale. Move the second
ruler under tension in a vertical (shear) direction along the
marked scale. The shear measurement is the amount that
the fabric shears before ripples appear on the surface of the
cloth. The amount can be measured on the vertical line of
the scale. The amount of recovery can also be measured.
The categories shown below were decided by judging
that any fabric with shear over 5 cm should be described as
‘high shear’, and then five divisions were created.

The shear characteristic scale (in cm)

1 2 3 4 5
High High– Medium Medium– Low-shear
shear medium low
5+ 4.9–3.5 3.4–2 1.9–0.5 0.4–0

Figure 9 Measuring shear. A method suitable for student practice. The card scale and a 20 cm square of fabric taped to two
rulers and the amount of shear measured on the scale.

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Drape
Drape is the ability of a fabric to hang in soft folds and to fit Method for student practice
around a figure, particularly in movement, without creating On a piece of thick white card mark a central point at the
angular distorted creases and buckles. The strain is often top. Mark a central line. Draw two lines at 45º each side of
across the fabric, thus good draping is needed across the the line. Divide the area each side of the line into five
fabric falling from flared shapes. The drape test done for sections. Mark them 1–5. Drive a nail or large drawing pin
these experiments concentrated on a crossway hanging test through the top point. Hang the corner of the 20 cm square
as this is a good guide to a fabric’s potential to drape. of fabric onto the point at the top centre. The drape category
Drape is a characteristic valued in many fabrics, it is only a can then be recorded.
part of that elusive quality ‘hand’. ‘Hand’ is a combination
of many qualities that will differ in different fabrics and The drape characteristic scale
this, I believe, is not measureable.
A simple assessment of the drape of a fabric, cut on the 1 2 3 4 5
straight grain, can be made by holding a gathered sample High- High– Medium Medium– Low-drape
piece vertically. The increased drop that would result from drape medium low
the weight of a larger piece of fabric would have to be taken
into account. The difficulty of assessing how fabric may A low-shear fabric will hang as a flat shape on the board;
behave in circular cut is demonstrated on page 21. therefore, in pattern cutting terms, low-drape means
Asymmetrical shapes, crossway cutting and the effects of virtually no drape. Note the difference in the two fabrics
joining different curve shapes would add further shown in Fig. 10.
complexity. The drapeometer test (BS 5058, see Appendix
Four), which drapes a 30 cm circle of cloth over a circular Equipment used for measuring the fabric drape
disk, has little relationship to the hang of clothing. The new recorded in this book
simple visual test, using a 20 cm sample piece, is only given The equipment described for student practice was used for
as guide across the five categories. the fabric codes recorded in this book.

Figure 10 Measuring drape. A method of measuring drape suitable for student practice. The left fabric records 1 (high-drape).
The right fabric records 4 (medium–low drape).

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Stretch
Stretch characteristics in fabrics offer the opportunity to cut The categories shown were decided by judging that any
close to the body without complex body shaping. Quite fabric which had a visual stretch of more than 5 cm should
simple shapes will fit closely to the body. Knitted fabrics be described as ‘high-stretch’, and then five divisions were
may stretch but their recovery can be weak. The created.
introduction of a small amount of elastane can make a
remarkable difference to its stability. The introduction of The stretch characteristic scale (in cm)
elastane into woven and knitted fabrics has penetrated a
large sector of the market, but there is still some resistance 1 2 3 4 5
to the rather ‘unnatural’ hang of some of the garments. The High- High– Medium Medium– Low-
amount a fabric will stretch can be measured; the stretch medium low stretch
instrument below will measure the maximum stretch 3.5+ 3.4–2.5 2.4–1.5 1.4–0.5 0.4–0
horizontally, followed by the stretch vertically. However,
these practical amounts are of little use if the fabric appears Close body fitting garments
visually unpleasant at very high stretch or near the stretch Four other measurements can be taken on the scale when
limits of the fabric. The basic pattern cutting shape has to cutting close body fitting garments in stretch fabrics.
be based on a basic ‘visual stretch’ measurement. On body (1) The horizontal visual ‘action’ stretch (visually
fitting garments or other garments, the designer has to acceptable stretch when the body is in action).
decide the amount of stretch that is visually acceptable (2) The vertical (warp) stretch of bi-stretch fabrics.
and then has to cut the garment pattern accordingly. (3) The decrease in measurement of the fabric vertically
This is the ‘visual stretch’ that is recorded in the work when the fabric is stretched horizontally.
in this book. (4) The amount of recovery after the fabric has been
stretched.
Method for student practice Percentages
Use the card scale created for measuring shear and stretch The percentage stretch can be calculated by the following
(see the diagram on page 25). Tape the 20 cm square of equation.
fabric onto the underside of two rulers using 2 cm of cloth
on each ruler. Place the first ruler firmly at the left-hand amount stretched 2 cm
× 100 e.g. × 100 = 12.5%
start of the scale. Move the second ruler under tension in a original length 16 cm
horizontal direction along the marked horizontal scale. The
‘visual stretch’ measurement in the weft direction is the Equipment used for measuring the fabric stretch
amount that the fabric stretches before it begins to distort recorded in this book
the fabric unpleasantly. The amount can measured on the A special piece of equipment was constructed that held the
horizontal line of the scale. The amount of recovery can fabric under tension between two bars. A photograph of it
also be measured. in use is shown in Appendix Three, page 213.

Figure 11 Measuring ‘visual stretch’. A method suitable for student practice. A 20 cm square of fabric taped to two rulers
and the amount of ‘visual stretch’ measured on a card scale.

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Fabric properties and 3D CAD images

A number of CAD software companies – for example measurements. These virtual figures can revolve, change
Browzwear, assyst-bullmer, Optitex and Lectra – have poses and perform many human movements.
developed software that creates the realisation of virtual In most companies many garment samples of designs are
garments in high resolution. Garment pattern pieces are made up but then discarded. CAD suppliers claim that 3D
joined together to create a 3D CAD image of a garment worn CAD realisation could reduce this apparent waste of time
by a virtual model figure that will demonstrate how the and materials because decisions could be made at an early
garment will look when finished. The mannequin’s skin, face stage in the design cycle. A further purported advantage is
and hair can be customised. The shape and size of the figure that the fit and stress of the garment can be measured
can be determined by the input of manual or body-scanned technically.

The companies have developed their

programs in such a way as to emphasise
different functions. Companies will select the
software that responds to their priorities. For
example, a design emphasis may focus on the
manipulation of colour, shape and printed
pattern in the development of a design range,
whilst other companies may be more
concerned with the fit, or the garment stress
of body movements in sportswear, industrial
wear or military activities.
However, the common denominator in all
the programs is the realisation of how the
fabric will determine the image of the
garment. This requires the input of the
measurements related to the mechanical
properties of the fabric, and the majority of
program developers are using The Kawabata
Evaluation Systems for Fabrics (KES-F TEST).
This is described in Appendix Four. It is
usually large companies that invest in these
CAD systems and they have access to fabric
testing laboratories that conduct these tests.
An example of the fabric properties
required can be seen in Figure 12: mass,
elongation, compression, bending rigidity, E-
modal, damping, thickness, wrinkling
tendency.
The images show how the garment shape
changes when different property values are
input into the system. Some systems allow
designers to use the sliders interactively to
examine how a change of fabric will affect the
design.
Students of CAD will find that an intuitive
knowledge of fabric behaviour, so necessary
for their manual pattern cutting, will also be
invaluable in any technological future.

Figure 12 Notice how the shape of the garment

is changed as the values for compression and
bending rigidity are altered. Photographs repro-
duced with permission of assyst-bullmer.

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