ISO 20947-3:2023

Performance evaluation protocol for digital fitting systems - Part 3: Digital fitting performance - Gap

This document specifies a protocol employed in evaluating the gap between the virtual garment and the virtual clone, the virtual twin or the virtual fit mannequin (fit form) model in the evaluation of the fitting performance of the virtual garment and the virtual human body.

Protocole d'évaluation de la performance des systèmes d'habillage virtuel — Partie 3: Performance de l'habillage virtuel - Écart

General Information

• Status: Published
• Publication Date: 03-Aug-2023
• ICS: 61.020 - Clothes
• Technical Committee: ISO/TC 133 - Clothing sizing systems - size designation, size measurement methods and digital fittings
• Drafting Committee: ISO/TC 133/WG 2 - Digital Fitting
• Current Stage: 6060 - International Standard published
• Start Date: 04-Aug-2023
• Due Date: 06-Mar-2023
• Completion Date: 04-Aug-2023

Overview

ISO 20947-3:2023 - "Performance evaluation protocol for digital fitting systems - Part 3: Digital fitting performance - Gap" defines a protocol to evaluate the gap between a virtual garment and a virtual human model (virtual clone, virtual twin or virtual fit mannequin). The standard is intended for objective assessment of fitting performance in digital fitting systems, including visualization and measurement of gap, garment pressure and related cross‑sectional metrics. It supports consistent comparison of digital fitting tools used in design, production and retail.

Key topics and requirements

• Scope and purpose: Specifies how to evaluate the space (gap) between virtual garment and virtual body in virtual cross sections to assess fit and comfort.
• Core functions (Clauses 4.2–4.7):
  • Perimeter measurement on virtual horizontal cross sections (circumference/girth).
  • Perimeter/length measurement on virtual vertical cross sections (front centre and side).
  • Gap measurement functions: circumference gap on horizontal sections and localized gap on vertical sections (side, centre front/back).
  • Tension map function to visualize surface strain distribution.
  • Garment pressure display to indicate tightness and potential comfort issues.
  • Grain display and projected cross-sectional garment view (top, front, side) for inspection.
• Quantitative evaluation (Clause 5): Describes area- and function-based methods to quantify gap and includes a method to relate virtual measures to physical gap measurements.
• Reporting (Clause 6 & Annex A): Provides a standardized format for evaluation reports to ensure repeatable comparison between systems.
• Terminology: Defines key terms such as digital fitting system, virtual garment, virtual human body, virtual cross section, gap, and garment pressure (see Clause 3).

Applications and users

• Who benefits:
  • Apparel designers and pattern engineers evaluating virtual garment fit.
  • Manufacturers selecting or validating digital fitting systems.
  • Retailers and e‑commerce platforms aiming to improve online fit guidance.
  • Educators and researchers working on fit, ergonomics and digital apparel simulation.
• Practical uses:
  • Replace or reduce physical prototyping by validating fit in virtual space.
  • Compare different digital fitting solutions using standardized gap and pressure metrics.
  • Improve wearer comfort and sizing decisions through objective gap and pressure analysis.

Related standards

• ISO 20947 series (this document is Part 3) - see related parts for broader digital fitting requirements.
• Definitions reference: ISO 20947-2:2020 (virtual garment) and ISO 18825-1:2016 (virtual human body).
• Prepared by ISO/TC 133 (Clothing sizing systems).

Keywords: ISO 20947-3:2023, digital fitting systems, virtual garment, virtual human body, virtual fit mannequin, gap measurement, garment pressure, virtual cross section, performance evaluation protocol.

Standards Content (Sample)

INTERNATIONAL ISO
STANDARD 20947-3
First edition
2023-08
Performance evaluation protocol for
digital fitting systems —
Part 3:
Digital fitting performance - Gap
Protocole d'évaluation de la performance des systèmes d'habillage
virtuel —
Partie 3: Performance de l'habillage virtuel - Écart
Reference number
© ISO 2023
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
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ISO copyright office
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Published in Switzerland
ii
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Functions . 2
4.1 General . 2
4.2 Function to measure the perimeter on the virtual cross section . 2
4.2.1 Function to measure the perimeter on the virtual horizontal cross section . 2
4.2.2 Function to measure the perimeter on the virtual vertical cross section
(front centre) . 8
4.2.3 Function to measure the perimeter on the virtual vertical cross section
(side) . 14
4.3 Function to measure the gap on the virtual cross section . 20
4.3.1 Function to measure the gap of circumference on the virtual horizontal
cross section .20
4.3.2 Function to measure the gap at side on the virtual vertical cross section
(front) . 27
4.3.3 Function to measure the gap at centre front or centre back on the virtual
vertical cross section (side) . 32
4.4 Tension map function .38
4.5 Garment pressure display function . 41
4.6 Grain display function.44
4.7 Display function for projected cross-sectional garment view . 47
4.7.1 General . 47
4.7.2 Top .48
4.7.3 Front . 50
4.7.4 Side . .56
5 Quantitative evaluation of digital fitting performance - Gap based on functions and
area measurements .61
5.1 General . 61
5.2 Method to measure a physical gap . 61
6 Report .66
Annex A (Normative) Format for report: Evaluation of a digital fitting performance .67
Bibliography .68
iii
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
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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.
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
Introduction
Digital fitting systems are used more frequently for evaluating the fit of garments without making
actual physical patterns or physical garments. In a digital fitting system, a virtual garment is made
using virtual patterns, and the fit of physical garment on a physical human body is assessed by draping
a virtual garment on a virtual body or a virtual fit mannequin (fit form) model. Such system is useful for
designers, manufacturers, educationalists because the system helps to improve the fit of garments and
productivity.
The use of the digital fitting system, employed to evaluate the suitability of a real garments on real
human body with the use of virtual garments on a virtual human body in virtual space, is growing
in popularity. The system eliminates the need for physical garment production with fabric in product
evaluation. Using a computer-generated virtual garment pattern, the virtual garment is created and
tested on either a virtual human body or a virtual fit mannequin (fit form) model. It benefits not only
those engaged in garment design but also consumers at the time of garment purchase, with better fit
and wider choice of sizes in mass-produced products.
Digital fitting technology is still developing, and there is a wide range of differences in the specification
and performance between digital fitting systems. This makes it difficult for users (designers,
manufacturers, educationalists and retailers of garments) to select an appropriate system for their
purposes.
This document evaluates gap, including garment pressure, which is an important factor in wearing
comfort.
The users of this document are those users planning to install or update digital fitting systems. This
document will help and provide judging criteria for selection of digital fitting system when garment
designer or pattern engineer create virtual garment patterns and evaluate fitting performance to
virtual fitting body.
The document should be viewed or printed in colour to clearly understand the performance evaluation
as indicated in the figures.
v
INTERNATIONAL STANDARD ISO 20947-3:2023(E)
Performance evaluation protocol for digital fitting
systems —
Part 3:
Digital fitting performance - Gap
1 Scope
This document specifies a protocol employed in evaluating the gap between the virtual garment and
the virtual clone, the virtual twin or the virtual fit mannequin (fit form) model in the evaluation of the
fitting performance of the virtual garment and the virtual human body.
2 Normative references
There are no normative references in this document.
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
3.1
digital fitting system
qualitative and/or quantitative evaluation of overall and/or specific simulation garment fit through
analysis of the distribution of surface strain, gap between body and garment, tension map, cross
section, surface wrinkles, garment balance, etc.
3.2
virtual garment
three-dimensional clothing in digital form that exists in virtual space
[SOURCE: ISO 20947-2:2020, 3.1.3]
3.3
virtual human body
virtual human model based on actual body dimensions used for digital fitting in the apparel industry,
including information such as size, shape, cross section, body texture and skeletal structure
[SOURCE: ISO 18825-1:2016, 2.1.1.2, modified — Notes to entry removed.]
3.4
virtual fit mannequin (fit form) model
virtual model based on approved dimensions used for draping and examining silhouette and fit of a
garment in a virtual space used for digital fitting
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
[SOURCE: ISO 18825-1: 2016, 2.2.2, modified — Notes to entry removed.]
3.6
gap
space between virtual garment and virtual human body or virtual fit mannequin (fit form model) which
is shown in virtual cross section
Note 1 to entry: The space changes depending on the weight of the clothes or the friction between the clothes and
the body.
Note 2 to entry: Space shall be expressed with difference amount of square measure or girth length between
virtual cross section of virtual garment and virtual human body or virtual fit mannequin (fit form) model or it
shall be expressed with gap amount between the virtual cross section of virtual garment and the virtual human
body or the virtual fit mannequin (fit form) model.
3.7
garment pressure
pressure (tightness) of a garment against a virtual body or a virtual fit mannequin (fit form) model
Note 1 to entry: Pressure is affected by gravity, friction, design and material properties.
4 Functions
4.1 General
The digital fitting system has six functions as given in 4.2 to 4.7.
4.2 Function to measure the perimeter on the virtual cross section
4.2.1 Function to measure the perimeter on the virtual horizontal cross section
This function measures the perimeter of the virtual garment and the virtual fit mannequin (fit form)
model from any arbitrary point on the virtual horizontal cross section. See Figure 1.
a)  Virtual clone or virtual twin, upper body garment
b)  Virtual clone or virtual twin, lower body garment
c)  Virtual clone or virtual twin, whole body garment
d)  Virtual fit mannequin, upper body garment
e)  Virtual fit mannequin, lower body garment
f)  Virtual fit mannequin, whole body garment
Key
1 silhouette line of front bodice
2 silhouette line of back bodice
3 silhouette line of right back pants
4 silhouette line of right front pants
5 silhouette line of left back pants
6 silhouette line of left front pants
Figure 1 — Example of the perimeter measured on the virtual horizontal cross section
4.2.2 Function to measure the perimeter on the virtual vertical cross section (front centre)
This function measures the length of the virtual garment shape and the virtual clone, the virtual twin
or the virtual fit mannequin (fit form) model shape from any arbitrary point on the virtual vertical
cross section (front). See Figure 2.
a)  Virtual clone or virtual twin, upper body garment
b)  Virtual clone or virtual twin, lower body garment
c)  Virtual clone or virtual twin, whole body garment
d)  Virtual fit mannequin, upper body garment
...