Technology

Integration of Computer Aided Design and
Smart Textiles to Prepare Multi-Functional
Sportswear: Diet-Facilitating Suit
By Jung Hyun Park, Pusan National University; Minyoung Suh, Kansas State University;
Dnyanada Satam, Eastman Chemical Company; and Hoon Joo Lee, North Carolina State University

Introduction

Due to increased pressures arising from technological advancements, new product design and
development has become essential in many areas,
including the sportswear sector. Recently, sports
activities rely on emerging technologies to develop
textiles that have high performance value and
varied applications. In addition, there is a growing
emphasis on multi-functional smart sportswear
since it enhances the wearers’ performance and
protects their body from extreme conditions
during activities. Therefore, the awareness of
comfort should be promoted in sportswear R&D.
Sportswear can be both comfortable and multifunctional when smart technical design is combined
with smart textile materials. Promoting this new
type of product can generate a niche market in the
sportswear industry, which has been rapidly
growing since the late 1990s.1,2
According to the World Health Organization
(WHO), over one billion of the world’s population
was found to be overweight or obese. A body mass
index (BMI) greater than or equal to 25 is defined
as overweight, while a BMI greater than or equal
to 30 indicates obesity.3 BMI is an index of weightfor-height that is used to classify underweight,
overweight, and obesity in adults. It is defined as a
person’s weight in kilograms divided by the square
of his or her height in meters.
As the number of overweight and obese people rises,
related health issues such as hypertension, diabetes, metabolic syndrome, heart disease, and breast
cancer also increase. Furthermore, the overweight
and the obese have a significant economic impact—
the estimated medical expenditure attributed to
obesity was US$147 billion in 2008.4 Although not
the only indicator of being overweight or ob; ese,
the measurement of waist circumference can reveal
excessive abdominal fat that increases the risk of

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various health issues. According to Lakka, et al.,
middle-aged men with this excess are candidates for
coronary heart disease, and therefore the amount of
abdominal fat is even more important than overall
overweight.5 Hypertension and high blood lipids
often cause coronary heart disease and are accelerated by increasing waist circumference.6 Due to the
awareness of these health risks, regardless of age,
and an increasing interest in health and well-being,
smart healthcare clothing, which monitor vital
signs such as blood pressure, heart rate, electrocardiogram (ECG), respiration, and body temperature,
has been developed and expanded.7-9 Research in
this area is facing various challenging issues such as
“biomedical sensors, scenarios of data security and
confidentiality, risk analysis, user interface, medical
knowledge/decision support, dissemination, user
acceptance and awareness, and business models
and exploitation.”10 Smart healthcare clothing can be
both comfortable and efficacious for disease
prevention when smart technical design is
combined with smart textile materials.
However, it is not easy to find sportswear developed
to help people practice weight management.
Demand for developing multi-functional smart
clothing is accelerating. Since the measurement of
waist circumference can be a useful indicator for
weight management, continuous self-monitoring
and physical activities will play an important role in
successful health management.11 Also, the use of
sensor and wireless communication technologies
in multi-functional healthcare clothing will likely
accelerate. Therefore, this research focuses on
developing smart multi-functional sportswear for
the overweight, called a diet-facilitating suit, using
smart textile materials that monitor the change of
waist circumference, body temperature, and the
amount of exercise.

Technology

Methodology

The major objective of this research was to design
multi-functional smart sportswear that measures
changes in body circumference and informs users
with relevant data. Fig. 1 presents the methodology
for this research, which was developed for prototyping smart sportswear that monitors waist
circumference for smart weight management. The
design concept included the garment design and the
positioning of technical devices in the garment. A
textile sensor, which is called an “e-strain gauge” in
this research, was developed using carbon black and
polyurethane. Cotton/spandex jersey knit fabric was
used as the major fabric. Body measurements of the
dress form were created using a 3D-body scanner,
and patterns were generated using computer aided
design (CAD). Fabric was automatically cut using
computer aided manufacturing (CAM) and garment
assembled by sewing. After an e-strain gauge was
embedded in the prototype, the prototype was tested
on a dress form.
Fig. 1.
Process of multi-functional smart sportswear development.

Fig. 2. Body shape for the overweight.

Design Considerations

To measure the circumference of the body accurately, the garment has to fit closely on the body.
Therefore, customized patterns for individuals are
recommended for fitting the garment. However,
current technology to make these customized
patterns is cumbersome and has low efficiency
compared to the production cost. Therefore, a
method to select body types in the shape categories
of torso, arms, and legs was proposed as a workable
solution. The users were fitted based on not only
their body size but also their body shape and
garment preference. First, the various body shapes
are reviewed.

Body Shapes of the Overweight

Body shapes of the overweight and the obese are
different from body shapes of others. Understanding
various body shapes is required to develop wellfitting garments for the overweight and the obese.
In this research, focus was on the torso shape rather
than discussing arms and leg shapes. In Fig. 2, the
rectangular-8 body shape is considered to be the
most even in scale regardless of the BMI value.
This shape is characterized by
well-proportioned torso curves.
The barrel body shape has a thicker
waist than the hips. The pear body
shape has a narrow-shouldered
torso where the body line meets
round hips and large bulging thighs.
Lastly, the box body shape has a
thick and wide torso, and wide hips
with no visible waistline.12,13
Role of CAD/CAM
Recently, automation that minimizes human intervention during
manufacturing became a hot issue
both in academia and the industry
since CAD/CAM provides solutions
to increase production efficiency
and to lower production cost.5
However, the apparel industry
still depends on skilled labor,
despite the advanced techniques
in automation, because industrial
applications of CAD/CAM in the
current apparel manufacturing are
limited to helping experts’ manual
operations due to the complexity
of standard body measurement

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Technology

methods.5,14,15 For example, fabric has anisotropic
mechanical properties and is too deformable to
predict its physical behavior, such as draping. In
addition, fabric interacts with an underlying body
when it is worn.
This section of the paper aims to understand masscustomized garment manufacturing. Major technical
issues that are represented by analyzing fully-automated garment production, such as construction of
a design database, 3D-body formation, mesh generation, and flattening are discussed in this section.
Mass-customization can be achieved when fullyautomated garment manufacturing is actualized.
Body Generation
A virtual interactive body model is determined by
nine perimeter parameters and three length parameters. When the parameter values are put into the
body model, the model is automatically modified
based on individual body size. This method cannot represent each body curve shape because only
perimeters and lengths are controlled rather than
the body shape which may follow the standard
body shape.10
Kim and Park separated “fit zone” from “fashion
zone.” Fit zone means the parts fitting closely to the
body shape, such as the upper part of bodice’s bust
level and the upper part of skirt’s hip level. The fit
zone is acquired by mapping the surface of a dress
form and is expressed as a B-spline surface. To easily
acquire fit zones from the raw data obtained from a
3D-body scanner without a complicated formation
process, their mapping method was used to adjust fit
zone parameters, such as key lengths and angles.14
Since garments do not follow complex body
surfaces in general, the garment model should be
put into a convex shape using a general dress form
by stereoscopy. The body model is then matched
to the garment model, and the garment model
is transformed into a convex shape covering the
body model. Therefore, Kang and Kim developed a
new method to create “body model” and “garment
model.” After sorting the raw data obtained from
the 3D-body scanner, they developed the body
model composed of cross-sectional points in the
cylindrical coordinate system. Landmarks such as
shoulder points, armhole points, and neck point
of the body model were determined using Fourier
series expansion.15,16

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Mesh Generation
After generating the 3D-garment model, a mesh
generation method is widely used to transform
3D-body scans into 2D-flat patterns.17-19 The surface
is divided into small pieces and the pieces are
recombined on a 2D plane. Two primary mesh
generation methods have been used: 1) the surface
is separated into several zones by specified lines
(e.g., center line, bust circumference line, and
shoulder line), and then each section is divided into
tiny pieces, or 2) the surface is entirely divided into
small pieces. Of these two methods, the former does
not create darts, while the latter generally
creates darts during the flattening process.15,19 Mesh
generation methods keep the size and arrangement
of the meshes constant. Therefore, the width and
height of zones are separated at regular intervals—
such processes generate triangular or quadrilateral
elements.14,20 The structure, which is well aligned
horizontally and vertically, is related to the control
of mesh sizes. It is important to determine the
optimal size of elements to create clear darts.
Fig. 3 shows the generation of triangular darts.
Triangulation is widely used to create meshes with
points from the raw data generated by a 3D-body
scanner while considering the curvature.21,22 Large
meshes are generated in low-curvature surfaces,
while small meshes are generated in high-curved
surfaces. The more triangles there are, the more
detailed expression there is.
Fig. 3. Triangular dart generation algorithm.

Quadrilateral mesh generation adopts the same
techniques as triangular mesh generation, while
saving more time. However, triangles are more
determinative than rectangles because the shape can
be determined with three lengths and three angles.
Hence, using a triangular structure can reduce the
number of control factors while developing and
generating an uncomplicated algorithm. When
triangular elements are combined, the subsequent
element is forced to attach to neighboring elements

Technology

until the difference between angles before and after
distortion does not exceed the predefined shear
tolerance value. If the angle difference exceeds the
tolerance, a dart is formed by detaching elements.
This algorithm creates darts in the perpendicular
direction with boundary lines of the pattern and
shows a tendency to have a smaller number of darts
with a larger shear angle allowance.
Flattening System
The goal of the former process (classic pattern
design) is to flatten the virtual garment image and
to develop garment patterns while the latter process
(virtual garment construction) is to estimate the
appearance of garments from 2D patterns.
Body size and shape varies based on the individual.
Although some people might have the same bust
size, their waist and hip circumferences might
differ. In addition, even if they have the same measurement in specific parts of the body, the flat degree
(angles in flat patterns generated due to curvy
body shape) and the cross sectional area can be
different. The obese and seniors especially show
different body shapes compared to general body
shapes. However, the conventional pattern making
system is based on grading technology that uses
a regression formula indicating the relationship
between average measurements and bust girth.
Therefore, mass production that applies the conventional pattern system cannot satisfy customers’
fit expectations. For structured suits or tight-fit
garments, fit is a critically important factor. A
2D-pattern generation system reflecting the curved
surface information of a body by using individual
3D-body scan data could be a solution to any
fit problems.

Material Consideration

An electrical strain (e-strain) gauge was developed
for use as a textile sensor by mixing carbon
black with polyurethane. When incorporated into
a garment, it can measure the change of
body circumference.

First, 6.25 g of polyurethane and 0.75 g of carbon
black were loaded into the Hakke MiniLab. The twin
screws were rotated for 10 min with a rotating speed
of 100 rpm at 200 °C for complete dispersion of
carbon black powders in the polyurethane elastomer. Finally, the polymer composite was extruded
through a 2-mm cylindrical die at room temperature
to produce the carbon black polyurethane composite
fiber (Fig. 4a).
Fig. 4. A (a) cylindrical and (b) flat e-strain gauge that consists
of polyurethane and carbon black.

To create a film of the e-strain gauge suitable for
laminating, this composite material was cut into
tiny pieces and pressed in a Hakke press (Thermo
Scientific). A carbon black concentration of 15 wt%
was used as a standard for this research since previous research showed that films at 20 wt% were brittle
and had low conductivity at 10 wt%. The mixture
was pressed between Teflon sheets with 700 kg force
at 200 °C for 15 min to acquire a film consisting of
carbon black and polyurethane using a heat pressure
machine (Fig. 4b).
Evaluation
The surface and cross-sectional area of the fiber
e-strain gauge were examined with a scanning electron microscope (SEM, Hitachi S-3200N) operated
at 5 kV and magnifications from 100× to 100K×.
Revolution (4pi Analysis) was used for the image
analysis of SEM images. Fig. 5 shows the cross
section of the e-strain gauges.
Fig. 5. The cross section of e-strain gauge.

E-Strain Gauge

Production
Pellethane 2355-80AE polyurethane elastomer was
supplied by Dow Chemical. Carbon black powder
with the density 1.7-1.9 g/cm3 was provided by
Cabot Corporation. Polyurethane pellets and carbon
black powders were mixed using the Hakke MiniLab
(Thermo Scientific) extruder.

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Technology

The electric resistance of e-strain gauges was
measured to evaluate the conductivity. All measurements were performed with a multimeter (EXTECH
420). E-strain gauges were stretched to a strain of
2.5% to 15%. Repetitive stretching and restoration
of the e-strain gauge were conducted respectively
for each strain. Measurements were repeated five
times at each level of strain and at each subsequent
relaxation. A rapid increase in electric resistance was
observed (Fig. 6).
Fig. 6. Relationship between strain and electric resistance of
the e-strain gauge

Fig. 7. A water droplet sitting on
top of superhydrophobic, highly
water-repellent, fabric.

is also known as self-cleaning or the Lotus effect.
Some researchers believe that superhydrophobic
fabric should have water roll-off at a roll-off angle
of smaller than 5°. However, roll-off angle should
not be used as a definition of superhydrophobicity
because the roll-off angle completely depends on the
drop volume and the contact angle hysteresis, which
is the difference between the advancing and the
receding contact angles when water begins to roll off
the fabric.
This amazing water repellency was obtained based
on two criteria: a low surface energy and a welldesigned surface roughness. The cotton/spandex
jersey knit fabric was treated with a fluorosilane
dissolved in isopropyl alcohol and was cured at 110
°C for 20 min. This treatment coated the fabric with
micro and nano protuberances that had low surface
energy (< 20 dyne/cm) and high water repellency.

Fabric Selection
Cotton fabric provides comfort, allowing good air
permeability and water absorption, while the high
elongation of spandex responds to changes from
active body movement. Hence, a 90% cotton/10%
spandex jersey knit fabric was used for the substrate
of the e-strain gauge, taking into consideration
moisture management and tight fit. The jersey knit
created a relatively lightweight fabric, compared to
fabrics constructed by other stitches, but stretched
more easily than woven fabrics. In addition, the fabric must be made superhydrophobic (highly water
repellent) since the garment consists of e-devices,
including e-strain gauge and multimeter. Also,
because this is sportswear, the fabric was treated
with nanosilver colloidal particles to give it antibacterial properties.
Superhydrophobicity
A superhydrophobic surface is defined as having a
water contact angle greater than 150° (Fig. 7). This
high contact angle is obtained by a combination of
surface chemistry and surface morphology (e.g.,
fabric construction). Water easily rolls off of a superhydrophobic surface, washing dirt off in the process
and effectively cleaning the surface, while keeping
the fabric material breathable. Superhydrophobicity
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Antimicrobials
Heavy metals are very reactive with proteins. The
ability of microorganisms to survive or grow rapidly
decreases in the presence of metals, reducing bacterial colonies. Metals bind to protein molecules,
inhibiting cellular metabolism and leading to microorganism death. Alteration of chemical structures
occurs. Metal toxicity is related to redox changes in
metal ions. One metal, silver, is well known to be
relatively non-toxic compared to other heavy metals
that are bacteriocidal.
Novel properties of nanomaterials have led to
breakthroughs in a multitude of cutting-edge technologies. Of particular interest to material scientists,
nanoscale materials have greater surface areas than
conventional materials. Therefore, in this research,
fabric was treated with nanosilver particles to inhibit
microorganism growth.

Prototype Sample Construction

A prototype of multi-functional smart sportswear
for the obese (Fig. 8) was manufactured to test
concept and performance. Body scanning and CAD
were used to generate customized patterns. The
patterns were created with the Gerber Accumark
Pattern Design System (PDS) software, taking into
account the stretch ratio for the chosen jersey knit

Technology

Fig. 8. Structure of the diet-facilitating suit (DFS).

fabric. Fabric was automatically cut using a Gerber
Cutting Edge Cutter. The prototype garment was
fitted on a dress form. After dressing the prototype
on the form, the electrical resistance of the e-strain
gauge was measured. An air inflatable package was
used to simulate change of body circumference.12
The single strain gauge was embedded around the
waist to insert elastics by casing (Fig. 8). The fabric
tape was made of the identical fabric as the suit and
stitched on the inside of the garment with running
stitches. Considering different degrees of technology
integration, the e-strain gauge could be permanently
integrated into the suit fabric by applying heat and
then lamination. However, physical embedment was
considered more appropriate due to the possible
changes in electrical properties of the e-strain gauge.

Monitoring

Changes of electrical resistance in the e-strain gauge
obtained from a multimeter can be sent to a cell
phone or other electronic devices over Bluetooth
daily or weekly. An appropriate software program
installed in the electronic devices transforms the
data to a user-friendly format, such as the amount of
body circumference changed. The electronic device
informs the user of estimated changes of body
circumference and provides dietary suggestions
along with a target level of aerobic exercise. In addition, an accelerometer (a Wireless Sensor Network,
WSN (Sun Microsystems) that detects magnitude,

Fig. 9. The motion detected by an accelerometer that
has been attached to the multi-functional smart sportswear.
The magnitude, direction, and speed of motion are
quantitatively measured.

direction, and speed of motion) attached to the
garment quantitatively measures the amount of
exercise (Fig. 9), and Radio Frequency Identification
(RFID) device has user’s health information such
as blood type, chronic disease, and recent health
record. While the user exercises, a Global Positioning System (GPS) can monitor the location of the
user for safety and security (Fig. 10).
Fig. 11 shows the prototype sample developed in this
research. Users can wear the garment and the service package regularly to continually monitor their
body status until they meet their target weights.
The use of such multi-functional smart apparel for
the overweight would help people maintain proper

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Technology

Fig. 10. The multi-functional smart sportswear for the overweight
(DFS users) that consists supporting electric devices.

weight and improve their health more strategically.
To enhance comfort of the product, a cotton/spandex blended jersey knit was designed with moisture
management properties to be comfortable during
users’ exercise. To make the apparel product fit the
user well, product patterns were developed using a
3D-body scanner and CAD/CAM.

Conclusion

A combination of apparel design, material science,
and cutting edge technologies were used in the
prototype of multi-functional smart sportswear
available for the overweight. The prototype was created using a 3D-body scanner and CAD. An e-strain
gauge was inserted into the waist of the prototype
garment, which was made of cotton/spandex jersey
knit fabric treated with nanosilver and a fluorosilane for antibacterial and self-cleaning effects. Waist
circumference change was simulated by air injection while electric resistance of the e-strain gauge
was measured. A multimeter was attached to the
garment to detect and monitor the magnitude,
direction, and speed of exercise motion. RFID,
with user’s health information, such as blood type,
chronic disease, and recent health record, was also
attached to this smart sportswear in case the user
experiences a medical emergency while exercising.
This research did not show which variables affected
the performance of the apparel on the human body,
therefore, the DFS prototype was not tested for
functionality. This study aimed to present the technologies required to develop multi-functional smart

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Fig. 11. Front view of the prototype
multi-functional smart sportswear
for the overweight.

sportswear and its potential use to prove the concept
by developing a prototype sample. The relationship
between electric resistance of the e-strain gauge
and waist circumference proved that both technical
design and material selection are important to
make mass-customized smart apparel. Such smart
sportswear can be both comfortable and multifunctional when smart technical design is combined
with smart textile materials. Promoting and
commercializing this new product can generate a
niche market in the sportswear industry and become
a stepping stone towards success in the future smart
apparel marketplace.

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Author

Hoon Joo Lee, Nike Inc., One Bowerman Drive,
Mia Hamm 2, Beaverton, OR 97005, USA; phone
+1.503.671.3178; HoonJoo.Lee@nike.com.

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DOI: 10.14504/ar.14.4.3

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