ISO 20947-1:2021
(Main)Performance evaluation protocol for digital fitting systems — Part 1: Accuracy of virtual human body representation
Performance evaluation protocol for digital fitting systems — Part 1: Accuracy of virtual human body representation
This document focuses on the method of quantifying the differences in body dimensions and visualizing shape differences between the human body and a virtual human body model. This document provides a performance evaluation protocol for virtual human body representation systems, which create virtual human body (including virtual fit mannequin) models based on 3D body scan data and/or body dimensions data of a human body. The required accuracy of a virtual human body depends on the purpose and use of the digital fitting system.
Protocole d'évaluation de la performance des systèmes d'habillage virtuel — Partie 1: Fidélité de la représentation du corps humain virtuel
General Information
Standards Content (Sample)
INTERNATIONAL ISO
STANDARD 20947-1
First edition
2021-07
Performance evaluation protocol for
digital fitting systems —
Part 1:
Accuracy of virtual human body
representation
Protocole d'évaluation de la performance des systèmes d'habillage
virtuel —
Partie 1: Fidélité de la représentation du corps humain virtuel
Reference number
©
ISO 2021
© ISO 2021
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ii © ISO 2021 – All rights reserved
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Basic requirements of virtual human modelling system .10
4.1 General .10
4.2 Data import function.11
4.3 Data export function .11
4.4 Landmark extraction and export function .11
4.5 Function to take body dimensions data .11
4.6 Cross section creation function .11
4.7 Visualization function .11
4.8 Symmetrisation function .11
5 Selection of subjects .11
6 Evaluation protocol for the virtual human body based on body dimensions .12
6.1 General .12
6.2 Virtual body dimensions .12
6.3 Errors in body dimensions .13
7 Cross sections and projection views .14
7.1 General .14
7.2 Cross section .15
7.3 Superimposed display of torso cross sections .15
7.4 Dimensions of bounding rectangles of cross sections .15
7.5 Front, back and side views .16
8 Report .16
8.1 General .16
8.2 Information on the virtual human modelling system .16
8.3 Availability of the recommended functions .16
8.4 Information on subject population .17
8.5 Measurement errors .17
8.6 Cross sections and projection views .17
Annex A (normative) Format for report: Evaluation of a virtual human modelling system .18
Annex B (informative) Example of report: Evaluation of a virtual human modelling
systembased on 3D body scan data .24
Annex C (informative) Example of report: Evaluation of a virtual human modelling
systembased on body dimension data .30
Annex D (informative) Example of report: Evaluation of a virtual human modelling
systemfor virtual fit mannequin models .37
Annex E (informative) Format for report: Evaluation of a virtual fit mannequin .42
Bibliography .46
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/ directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www .iso .org/ patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO's adherence to the
World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www .iso .org/
iso/ foreword .html.
This document was prepared by Technical Committee ISO/TC 133, Clothing sizing systems - size
designation, size measurement methods and digital fittings.
A list of all parts in the ISO 20947 series can be found on the ISO website.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www .iso .org/ members .html.
iv © ISO 2021 – All rights reserved
Introduction
Digital fitting systems are used for evaluating the fit of a garment without making physical patterns
or physical garments. In a digital fitting system, a virtual garment is made using virtual patterns, and
the fit of physical garment(s) on a physical human body is assessed by draping a virtual garment on a
virtual human body or a virtual fit mannequin (fit form). Such systems are useful for designers and
manufacturers, educationalists and retailers of garments because the system helps to improve the fit
of garments and productivity. It can also be useful for consumers for assessing the fit of mass-produced
garments, for online shopping or for selecting an appropriate size.
The digital fitting system enables examination of the fit of a garment by placing a virtual garment on
a virtual human body. Greater accuracy in examining the fit of the virtual garment requires a virtual
human body representing the human body accurately. There are several methods for creating the
virtual human body. The most popular is the use of a 3D body scan data of a human body, scan data
of a fit mannequin representing a specified human form and a parametric model created from body
dimensions.
This document defines the virtual human body system that forms the basis of the digital fitting
system. This document establishes not only the basic functional requirements of this system but also
the protocol for assessing the quality of the virtual human body. The protocol is expected to enable
users of digital fitting systems (designers, educationalists and retailers) to choose the virtual human
body system most appropriate for their purposes and, at the same time, realize easier performance
evaluation of digital fitting systems that make use of the virtual human body (including virtual fit
mannequin) model. Since the accuracy of scan-derived measurements and surface shape depends
on the accuracy of 3D body scanner system used, manual measurements are used for quantitatively
evaluating the accuracy of a virtual human body. Accuracy of scan-derived measurements should be
evaluated according to ISO 20685-1.
INTERNATIONAL STANDARD ISO 20947-1:2021(E)
Performance evaluation protocol for digital fitting
systems —
Part 1:
Accuracy of virtual human body representation
1 Scope
This document focuses on the method of quantifying the differences in body dimensions and visualizing
shape differences between the human body and a virtual human body model. This document provides
a performance evaluation protocol for virtual human body representation systems, which create
virtual human body (including virtual fit mannequin) models based on 3D body scan data and/or body
dimensions data of a human body. The required accuracy of a virtual human body depends on the
purpose and use of the digital fitting system.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 8559-1, Size designation of clothes — Part 1: Anthropometric definitions for body measurement
ISO 18825-1, Clothing — Digital fittings — Part 1: Vocabulary and terminology used for the virtual human
body
ISO 18825-2, Clothing — Digital fittings — Part 2: Vocabulary and terminology used for attributes of the
virtual human body
ISO 20685-1, 3-D scanning methodologies for internationally compatible anthropometric databases —
Part 1: Evaluation protocol for body dimensions extracted from 3-D body scans
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at http:// www .electropedia .org/
3.1
digital fitting system
fitting system that provides qualitative and/or quantitative evaluations of overall and/or specific
simulation garment fit through analysis of the distribution of surface strain, gap between body and
garment, heat map, cross section, surface wrinkles, seam drop, garment balance, etc.
3.2
virtual human modelling system
system for creating a virtual human body (3.3.2) for a specific market or individual
Note 1 to entry: Asymmetrical shape assumed to match the body shape of the individual.
3.3
virtual human model
three-dimensional model in digital format
[SOURCE: ISO 18825-1: 2016, 2.1.1]
3.3.1
parametric human body
virtual human model (3.3) with changeable parameters such as size and shape, etc.
Note 1 to entry: Parametric human body is created by modifying the parameters of the exemplar model imported
from the 3D model library. The exemplar models vary by country as they are based on a database. Therefore, a
parametric human body can be made on the basis of height variations, BMI (body mass index) and so on.
Note 2 to entry: The parameters of the parametric human body are presented in the parametric human body
software. The parameters of the parametric human body can be added depending on the purpose of users.
Note 3 to entry: to entry See Figure 1.
Figure 1 — Examples of parameters of a male adult body
[SOURCE: ISO 18825-1: 2016, 2.1.1.1]
3.3.2
virtual human body
virtual clone (3.3.2.1) for digital fitting in the apparel industry, including information such as size, shape,
cross section, body texture and skeletal structure
Note 1 to entry: Also called “fashion avatar”. In computing, an avatar is the graphical representation of the user
or the user’s alter ego or character.
Note 2 to entry: The virtual human body is classified into two key types: virtual clone and virtual twin.
Note 3 to entry: In this document, virtual human body includes at least virtual clone, virtual twin and virtual fit
mannequin model.
[SOURCE: ISO 18825-1: 2016, 2.1.1.2, modified — Note 3 to entry has been added.]
2 © ISO 2021 – All rights reserved
3.3.2.1
virtual clone
virtual shape
virtual human body (3.3.2) that is created by forming three-dimensional surface data from a 3D
body scanned, using surface modelling processes including noise elimination, hole-filling and mesh
generation
Note 1 to entry: It is essential that a user be scanned first to create a virtual clone.
Note 2 to entry: The virtual clone is identical to the body shape of the user.
Note 3 to entry: See Figure 2.
Key
1 3D scanning
2 3D scanned point cloud
3 virtual clone
Figure 2 — Process of creating a virtual clone
[SOURCE: ISO 18825-1: 2016, 2.1.1.2.1]
3.3.2.2
virtual twin
virtual size
virtual human body (3.3.2) morphed according to body dimensions acquired either through manual or
automatic measurements
Note 1 to entry: The virtual twin is a parametric human body (3.3.1) as it can be altered with parameters.
Note 2 to entry: The virtual twin is not identical to the user; but is a close approximation that can be altered by
entering parameters retrieved from a population database.
Note 3 to entry: See Figure 3.
Note 4 to entry: A virtual twin can be created directly from the person being scanned or as in case of most digital
systems from an existing library.
a) Body measurements b) 3D model library c) Virtual twin
NOTE Body measurements are necessary to create a virtual twin.
Figure 3 — Process of creating a virtual twin
[SOURCE: ISO 18825-1: 2016, 2.1.1.2.2, modified — “that is applied” has been replaced by “according to”
and Note 4 to entry has been added.]
3.3.2.3
virtual fit mannequin
virtual human body (3.3.2) that represents an actual human body model in digital format used for
garment visualization
Note 1 to entry: The model is used for draping simulation (3D form and design realization for example) and
examining silhouette and fit of a garment.
Note 2 to entry: See Figure 4.
Figure 4 — Process of creating a virtual fit mannequin
4 © ISO 2021 – All rights reserved
3.4
virtual standing position
posture of a virtual human model (3.3) used for measuring dimensions and fit
Note 1 to entry: In a virtual standing position, the head is in the Frankfurt plane, the long axes of the feet should
be parallel to one another and 200 mm apart. The upper arms are abducted to form a 20° angle with the sides
of the torso and the elbows are straight. But the palms face toward the torso. This position shall be used for
evaluating the fit of garments.
3.5
virtual cross section
closed contour extracted from the plane cutting a virtual body segment perpendicular to its main axis
or the three principle axes
Note 1 to entry: See Figure 5.
Note 2 to entry: The main axis is the axis that connects the joints on either side of the virtual body segment.
Figure 5 — Examples of virtual body cross sections
[SOURCE: ISO 18825-1: 2016, 2.2.2]
3.6
virtual body landmarks and levels
points that define the characteristic of the body shape of the user in the virtual standing position (3.4)
Note 1 to entry: For example, points of bone prominence, peak points on a convex or concave surface, or points
like the bust point can be virtual body landmarks.
Note 2 to entry: On a physical body, a virtual fit mannequin or a physical fit mannequin, the landmarks and the
levels are defined in the same manner.
Note 3 to entry: Some of the landmarks are evaluated in terms of their levels in this document (see Table 1).
Note 4 to entry: When a physical body or a physical fit mannequin is 3D scanned, markers for the landmarks can
be put on it to extract their positions.
[SOURCE: ISO 18825-1:2016, 2.2.4]
Table 1 — Virtual and physical body landmark points and levels
No. Virtual body landmark points Male/Female
1 Virtual back neck-base point both
2 Virtual shoulder point (Right and Left) both
3 Virtual axilla point male
4 Virtual bust point female
5 Virtual underbust point female
6 Virtual midriff level female
7 Virtual side waist point (Right and Left) both
8 Virtual back waist point both
9 Virtual top hip level both
10 Virtual hip point both
11 Virtual crotch point both
12 Virtual gluteal fold point both
13 Virtual elbow point (Right and Left) both
14 Virtual wrist point (Right and Left) both
15 Virtual side neck-base point (Right and Left) both
16 Virtual landing heel point both
3.6.1
virtual back neck-base point
most posterior point at the back neck-base on the midsagittal plane with the virtual human body (3.3.2)
in the virtual standing position (3.4)
[SOURCE: ISO 18825-2:2016, 2.1.5]
3.6.2
virtual shoulder point
most lateral point of the shoulder ridge line passing through the cross section covering the middle plane
of the torso and arm with the virtual human body (3.3.2) in the virtual standing position (3.4)
[SOURCE: ISO 18825-2:2016, 2.1.6]
3.6.3
virtual axilla point
lowest point under the axillary passing through the cross section between the torso and arm with the
virtual human body (3.3.2) in the virtual standing position (3.4)
[SOURCE: ISO 18825-2:2016, 2.1.7]
3.6.4
virtual bust point
most anterior point of the bust with the virtual human body (3.3.2) in the virtual standing position (3.4)
Note 1 to entry: This point is used for a female.
[SOURCE: ISO 18825-2:2016, 2.1.10, modified — Note 1 to entry modified.]
3.6.5
virtual underbust point
lowest point or its level under the bust projection with the virtual human body (3.3.2) in the virtual
standing position (3.4)
Note 1 to entry: This point is used for a female.
6 © ISO 2021 – All rights reserved
[SOURCE: ISO 18825-2:2016, 2.1.11, modified — "or its level" has been added, Note 1 to entry has been
modified.]
3.6.6
virtual midriff level
midway between the levels of the virtual underbust point and virtual side waist point
Note 1 to entry: This level is used for a female.
Note 2 to entry: [SOURCE: ISO 8559-1:2017, 3.1.21, modified — Term and definition modified to apply to the
virtual human body, Note 1 to entry modified.]
3.6.7
virtual side waist point
most concave point or its level of the (right) side waist when viewed from the front with the virtual
human body (3.3.2) in the virtual standing position (3.4)
[SOURCE: ISO 18825-2:2016, 2.1.12]
3.6.8
virtual back waist point
point of the back waist on the midsagittal plane at the level of the virtual side waist point (3.6.7) with the
virtual human body (3.3.2) in the virtual standing position (3.4)
[SOURCE: ISO 18825-2:2016, 2.1.13]
3.6.9
virtual top hip level
midway between the level of the virtual side waist point and virtual side hip point
[SOURCE: ISO 8559-1:2017, 3.1.24, modified — Term and definition modified to apply to the virtual
human body.]
3.6.10
virtual hip point
most posterior point of the hip when viewed from the front when the virtual human body (3.3.2) is in a
virtual standing position (3.4)
[SOURCE: ISO 18825-2:2016, 2.1.15, modified — “when viewed from the front” has been added.]
3.6.11
virtual crotch point
lowest point of the torso on the midsagittal plane with the virtual human body (3.3.2) in the virtual
standing position (3.4)
[SOURCE: ISO 18825-2:2016, 2.1.16]
3.6.12
virtual gluteal fold point
most concave point on the sagittal plane passing through the virtual hip point (3.6.10) between hip and
thigh or its level with the virtual human body (3.3.2) in the virtual standing position (3.4)
[SOURCE: ISO 18825-2:2016, 2.1.20]
3.6.13
virtual elbow point
most protruding point of the elbow
[SOURCE: ISO 18825-2:2016, 2.1.17]
3.6.14
virtual wrist point
most concave point of the extended line of the little finger passing through the cross section between
the arm and hand with the virtual human body (3.3.2) in the virtual standing position (3.4)
[SOURCE: ISO 18825-2:2016, 2.1.18]
3.6.15
virtual side neck-base point
intersection point of the concave contour line at the neck-base passing through the shoulder ridge line
with the virtual human body (3.3.2) in the virtual standing position (3.4)
[SOURCE: ISO 18825-2:2016, 2.1.4]
3.6.16
virtual landing heel point
lowest point or level of the posterior calcaneus with the virtual human body (3.3.2) in the virtual standing
position (3.4)
Note 1 to entry: The virtual landing heel point can reach the floor or the top of the shoe heel.
[SOURCE: ISO 18825-2:2016, 2.1.26, modified — "or level" has been added, Note 1 to entry has been
modified.]
3.7
virtual body dimensions
size information on virtual body segments of the virtual human body (3.3.2) that corresponds to
measured anthropometric dimensions of the user in the virtual standing position (3.4)
Note 1 to entry: See 6.2.
3.7.1
virtual chest girth
horizontal girth of the torso passing through the virtual axilla point (3.6.3) with the virtual human body
(3.3.2) in the virtual standing position (3.4)
[SOURCE: ISO 18825-2:2016, 2.2.17]
3.7.2
virtual bust girth
horizontal girth of the torso passing through the virtual bust point (3.6.4) with the virtual human body
(3.3.2) in the virtual standing position (3.4)
[SOURCE: ISO 18825-2:2016, 2.2.18]
3.7.3
virtual underbust girth
horizontal girth of the torso passing through the virtual underbust point (3.6.5) with the virtual human
body (3.3.2) in the virtual standing position (3.4)
[SOURCE: ISO 18825-2:2016, 2.2.19]
3.7.4
virtual waist girth
horizontal girth of the torso passing through the virtual side waist point (3.6.7) with the virtual human
body (3.3.2) in the virtual standing position (3.4)
[SOURCE: ISO 18825-2:2016, 2.2.20]
8 © ISO 2021 – All rights reserved
3.7.5
virtual hip girth
horizontal girth of the torso passing through the virtual hip point (3.6.10) with the virtual human body
(3.3.2) in the virtual standing position (3.4)
[SOURCE: ISO 18825-2:2016, 2.2.22]
3.7.6
virtual thigh girth
horizontal girth of the leg at the level of virtual gluteal fold point (3.6.12) with the virtual human body
(3.3.2) in the virtual standing position (3.4)
[SOURCE: ISO 18825-2:2016, 2.2.23, modified — "virtual crotch point" has been changed to "virtual
gluteal fold point".]
3.7.7
virtual chest height
vertical distance between the virtual landing heel point (3.6.16) and virtual axilla point (3.6.3) with the
virtual human body (3.3.2) in the virtual standing position (3.4)
3.7.8
virtual bust height
vertical distance between the virtual landing heel point (3.6.16) and virtual bust point (3.6.4) with the
virtual human body (3.3.2) in the virtual standing position (3.4)
[SOURCE: ISO 18825-2:2016, 2.2.2]
3.7.9
virtual underbust height
vertical distance between the virtual landing heel point (3.6.16) and virtual underbust point (3.6.5) with
the virtual human body (3.3.2) in the virtual standing position (3.4)
3.7.10
virtual waist height
vertical distance between the virtual landing heel point (3.6.16) and virtual side waist point (3.6.7) with
the virtual human body (3.3.2) in the virtual standing position (3.4)
[SOURCE: ISO 18825-2:2016, 2.2.3]
3.7.11
virtual hip height
vertical distance between the virtual landing heel point (3.6.16) and virtual hip point (3.6.10) with the
virtual human body (3.3.2) in the virtual standing position (3.4).
[SOURCE: ISO 18825-2:2016, 2.2.4]
3.7.12
virtual thigh height
vertical distance between the virtual landing heel point (3.6.16) and virtual gluteal fold point (3.6.12)
with the virtual human body (3.3.2) in the virtual standing position (3.4)
3.7.13
virtual arm length
sum of the distance of the straight line between virtual shoulder point (3.6.2) and virtual elbow point
(3.6.13), and the distance of the straight line between virtual elbow point and virtual wrist point (3.6.14)
with the virtual human body (3.3.2) in the virtual standing position (3.4)
Note 1 to entry: In case ‘virtual arm length’ is used to mean ‘surface length’, it should be marked that there has
been a change in meaning.
Note 2 to entry: In this document virtual arm length is mainly used to mean surface length.
[SOURCE: ISO 18825-2:2016, 2.2.10, modified — Notes 1 and 2 to entry have been modified.]
3.7.14
virtual upper arm girth
maximum girth of the upper arm perpendicular to the main axis of the upper arm and passing through
the virtual axillia point (3.6.3) with the virtual human body (3.3.2) in the virtual standing position (3.4)
[SOURCE: ISO 18825-2:2016, 2.2.14]
3.7.15
virtual wrist girth
girth of the forearm perpendicular to the main axis of the forearm and passing through the virtual wrist
point (3.6.14) with the virtual human body (3.3.2) in the virtual standing position (3.4)
[SOURCE: ISO 18825-2:2016, 2.2.16]
3.7.16
virtual inside leg height
vertical distance between the virtual landing heel point (3.6.16) and virtual crotch with the virtual
human body (3.3.2) in the virtual standing position (3.4)
[SOURCE: ISO 18825-2:2016, 2.2.5, modified — The term "virtual crotch height" has been deleted.]
3.7.17
virtual centre back waist length
surface distance between the virtual centre back neck-base point and the virtual centre back waist
point with the virtual human body (3.3.2) in the virtual standing position (3.4)
[SOURCE: ISO 18825-2:2016, 2.2.9, modified — "Centre" was added to the term and to the definition.]
3.7.18
virtual shoulder width
horizontal distance between right and left virtual shoulder points (3.6.2)
Note 1 to entry: In case ‘virtual shoulder width’ is used to refer to ‘surface length’, it should be marked that there
has been a change in meaning.
[SOURCE: ISO 18825-2:2016, 2.2.8]
3.7.19
virtual shoulder slope
values, in degrees, of the angles of inclination of a line joining the(virtual) shoulder point and the
(virtual) side neck-base point against the horizontal plane
Note 1 to entry: The difference (in mm) between levels of the (virtual) shoulder point and the (virtual) side neck-
base point may be used (see ISO 8559-1:2017, Figure 115).
3.7.20
virtual shoulder length
surface distance between a virtual shoulder point (3.6.2) and a virtual side neck-base point (3.6.15) in the
right and left side of a virtual human body (3.3.2)
4 Basic requirements of virtual human modelling system
4.1 General
The virtual human modelling system shall have the following functions.
10 © ISO 2021 – All rights reserved
4.2 Data import function
The system shall have the function to import body surface shape data and/or body dimensions data of
any human body. It is recommended that the system is able to import the location of landmarks.
4.3 Data export function
The system shall have the functionality to export a virtual human body in a format, which is available
to digital fitting systems, such as Wavefront .obj format. Namely, the virtual human body is a closed
polyhedron consisting of triangular elements without self-intersections, and the two sides of each
triangle are consistent for the entire body. The order is fixed for the three vertices of each triangle, and
the side appearing to be counter clockwise in direction is defined as an exterior side.
4.4 Landmark extraction and export function
The system shall have the functionality to extract the virtual body landmarks and levels when they are
not imported. The system should have the functionality to export the landmarks and levels listed in
Table 1 on the virtual human body.
4.5 Function to take body dimensions data
The system shall have the functionality to measure body dimensions listed in Table 2 on the virtual
human body in accordance with ISO 18825-2 or ISO 8559-1. For a virtual fit mannequin model, the
system shall have the function to measure body dimensions corresponding to those of a human body if
the virtual fit mannequin model has the landmarks to define the dimensions.
4.6 Cross section creation function
The system shall have the function to create the virtual cross sections listed in Table 3 on the virtual
human body in accordance with ISO 18825-2. The system also shall have the function to create cross
sections of the imported human body data. For a virtual fit mannequin model, the system shall have
the function to create cross sections of the virtual fit mannequin model corresponding to virtual cross
sections of a virtual shape.
The system shall have the function to create the virtual bounding rectangles of the cross sections. The
virtual bounding rectangle is the minimum rectangle containing the cross section, and whose edges
are in the lateral or anteroposterior direction.
4.7 Visualization function
The system shall have the function to visualize the virtual human body in 3D form. Additionally, the
system should be able to show the specified body dimensions and cross section positions over the
model.
4.8 Symmetrisation function
The system should have the function to create a symmetrical virtual human body even if the imported
3D body scan data is asymmetrical.
5 Selection of subjects
Subjects shall reflect approximately the same range of body sizes and shape variations expected in
the population for which the virtual human body system is intended. The subjects shall also include
a variety of body types — not just people of average height and weight. If children are included in the
intended population, it is particularly important that the subjects cover the age range of the intended
population.
At least three persons shall be selected for men and for women, including three levels representing the
distribution (near the 5th percentile, near the average, and near the 95th percentile) in height, and bust
or chest girth. Nine persons should be selected including combinations of the 3 levels in each of height,
and bust or chest girth. In case of virtual fit mannequins, the subjects of at least three sizes also shall be
selected according to the distribution in height and bust or chest girth of the intended population.
6 Evaluation protocol for the virtual human body based on body dimensions
6.1 General
The accuracy of the virtual human body in representing the body dimensions of a specific human
body is quantified with the following method (see Figure 6). Particularly a virtual clone and a virtual
fit mannequin model are evaluated with the method. In addition, when the accuracy of a virtual fit
mannequin to a physical fit mannequin is evaluated, the method is also applicable when substituting a
human body with a physical fit mannequin. On the other hand, a virtual size and a virtual fit mannequin
(scanned human data) shall be compared without dimensions but only using the cross sections as
described in Clause 7 since these virtual models are generated from body dimensions.
Figure 6 — Evaluation with body dimensions
(left: physical human body, right: virtual human body)
6.2 Virtual body dimensions
The body dimensions shown in Table 2 shall be acquired for both the human body and the virtual
human body for each of the selected subjects. In case of evaluation for a virtual clone, both of left and
right sides should be measured for the thigh girths, the arm lengths, the upper arm girths, the wrist
girths, the shoulder slopes and the shoulder lengths. For virtual twin or virtual fit mannequin, which
12 © ISO 2021 – All rights reserved
may be treated as symmetrical, one of a left or right side is measured. If necessary, evaluation of items
other than those shown in Table 2 may be added. Most of them are defined in ISO 18825-2, but virtual
chest height, Virtual underbust height, Virtual thigh height, Virtual shoulder slope and Virtual shoulder
length are newly defined below. The girths for the virtual human body shall be measured, assuming a
tape measure is used, measuring the circumference and not the contours.
Human body dimensions shall be measured in accordance with ISO 8559-1. Measurement values of the
virtual human body shall be acquired in the virtual standing position as given in ISO 18825-1, using the
measurement function of the virtual human modelling system. If generating the virtual human body
from 3D body scan data, the body shall be measured in standing position A of ISO 20685-1.
In case of a virtual human body without its feet or legs, the waist or hip height of a physical body and
the virtual human body are assumed to be the same value and treated as a reference height.
Table 2 — Body dimensions used in evaluation
Virtual body dimension Requirement
1 Virtual chest girth required for male
2 Virtual bust girth required for female
3 Virtual underbust girth required for female
4 Virtual waist girth required
5 Virtual hip girth required
6 Virtual thigh girth (right) essential
7 Virtual thigh girth (left) essential
8 Virtual chest height required for male
9 Virtual bust height required for female
10 Virtual underbust height required for female
11 Virtual waist height required
12 Virtual hip height required
13 Virtual thigh height (right) essential
14 Virtual thigh height (left) essential
15 Virtual arm length (right) required
16 Virtual arm length (left) required
17 Virtual upper arm girth (right) required
18 Virtual upper arm girth (left) required
19 Virtual wrist girth (right) required
20 Virtual wrist girth (left) required
21 Virtual inside leg height required
22 Virtual centre back waist length required
23 Virtual back neck point to waist required
24 Virtual shoulder width required
25 Virtual shoulder slope (right) required
26 Virtual shoulder slope (left) required
27 Virtual shoulder length (right) required
28 Virtual shoulder length (left) required
6.3 Errors in body dimensions
Error is calculated by subtracting human body dimension value from virtual human body dimension
value (mm). For each item, the maximum, the minimum, the mean, and the standard deviation of the
error, as well as the mean absolute error are calculated.
The maximum, the minimum, the mean and the standard deviation of numbers of vertices in the virtual
human bodies without heads, hands or feet shall be reported. If all of the numbers in the virtual human
bodies are common, their maximum, minimum, mean, standard deviation are not necessary to be
reported.
7 Cross sections and projection views
7.1 General
Two dimensional shapes of the virtual human body and that of the human body are shown for visual
inspection. The cross section, front, back and side views for both the human body and the virtual
human body are obtained and presented with the following method (Figure 7). To acquire the cross
sectional view of the human body, 3D body scanner and sliding gauge may be used. A virtual clone
whose accuracy is well assessed, can be used as a reference in evaluation for a virtual twin or a virtual
fit mannequin. Examples of report for the evaluation of a virtual twin or virtual fit mannequin are
shown in Tables E.1 to E.3.
Figure 7 — Evaluation with cross sections
(left: scanned human data, right: virtual twin)
14 © ISO 2021 – All rights reserved
Table 3 — Body cross sections used in evaluation
Cross section Level Requirement
1 Chest cross section Virtual axilla point (right) required for male
2 Bust cross section Virtual bust point (right) required for female
3 Underbust cross section Virtual underbust point optional for female
4 Midriff cross section Virtual midriff level optional for female
5 Waist cross section Virtual side waist point required
6 Top hip cross section Virtual top hip level required
7 Hip cross section Virtual hip point required
Virtual gluteal fold
8 Thigh cross section (right) required
point(right)
Virtual gluteal fold point
9 Thigh cross section (left) required
(left)
7.2 Cross section
Each of cross sections in Table 3 (six for males and eight for females) is presented as follows. The
cross section of the virtual human body is superimposed on that of the human body in a way that the
centres of bounding rectangles of the two cross section shapes match. The cross sections are shown
with the front of the body facing downward. The two cross sections are drawn with lines in clearly
distinguishable colours or colour densities. The lines should be thick enough to clearly show the cross-
sectional shape. The bounding rectangles, whose edges are in the lateral or anteroposterior direction
are also superimposed on the cross sections.
NOTE See the first part of Table C.7.
7.3 Superimposed display of torso cross sections
A diagram showing the bust (chest for men), waist and hip cross sections projected in the vertical
direction is created for each person for assessing the posture in the standing position, e.g. degree of
chest prominence or rounding shoulder. Diagrams of the human body and the virtual human body are
shown side by side, with the front facing downward. The three cross sections are drawn with lines that
are thick enough to clearly show the shape and in clearly distinguishable colours or colour densities.
NOTE See second part of Table C.7.
7.4 Dimensions of bounding rectangles of cross sections
The lateral and anteroposterior dimensions of the bounding rectangle are obtained for bust (chest for
men), underbust (only for women), waist, and hip cross sections of both the virtual human body and the
human body. The width and depth of the bounding rectangle are calculated as the lateral dimension
divided by the anteroposterior dimension.
NOTE See Table C.8.
Key
1 bounding rectangle
h anteroposterior dimension (h mm)
w lateral dimension (w mm)
a
Width and depth = w÷h.
Figure 8 — Dimensions of bounding rectangle of cross section
7.5 Front, back and side views
The front, back and side views of the human body and the virtual human body are presented side
by side. The head can be excluded from display. The views of the human body are its photographs or
images from its 3D body scanned data. The positions for the bust (chest for men), under bust (only for
women), waist, and hip cross-sections are shown on the front, back and side views with line segments.
The superimposed silhouette image of the human body and the virtual human body are also presented
on each of the front, back and side views.
NOTE See Table C.9.
8 Report
8.1 General
Available functions, information on subjects used for evaluation, and results of evaluation using body
dimensions, cross sectional shapes, and frontal and side views shall be reported using formats in
Annex A. Examples of report are also shown in Tables B.1 to B.7, Tables C.1 to C.9 and Tables D.1 to D.3.
8.2 Information on the virtual human modelling system
Ge
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