ISO/IEC TS 23884:2021

TECHNICAL ISO/IEC TS
SPECIFICATION 23884
First edition
2021-12
Information technology — Computer
graphics, image processing and
environmental data representation
— Material property and parameter
representation for model-based haptic
simulation of objects in virtual, mixed
and augmented reality (VR/MAR)
Technologies de l'information — Infographie, traitement d'images
et représentation des données environnementales — Propriété
matérielle et représentation des paramètres pour la simulation
haptique basée sur un modèle d'objets en réalité virtuelle, mixte et
augmentée
Reference number
© ISO/IEC 2021
© ISO/IEC 2021
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii
© ISO/IEC 2021 – All rights reserved

Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms, definitions and abbreviated terms . 1
3.1 Terms and definitions . 1
3.2 Abbreviated terms . 2
4 Overview: Material properties for haptic simulation . 2
4.1 General . 2
4.2 Stiffness . 4
4.3 Friction . 4
4.4 Object texture . 6
5 Material property representation 1: extended material node . 6
6 Haptic rendering node .7
7 Conformity . . 8
Bibliography .10
iii
© ISO/IEC 2021 – All rights reserved

Foreword
ISO (the International Organization for Standardization) and IEC (the International Electrotechnical
Commission) form the specialized system for worldwide standardization. National bodies that are
members of ISO or IEC participate in the development of International Standards through technical
committees established by the respective organization to deal with particular fields of technical
activity. ISO and IEC technical committees collaborate in fields of mutual interest. Other international
organizations, governmental and non-governmental, in liaison with ISO and IEC, also take part in the
work.
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 document 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 or
www.iec.ch/members_experts/refdocs).
Attention is drawn to the possibility that some of the elements of this document may be the subject
of patent rights. ISO and IEC 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) or the IEC
list of patent declarations received (see https://patents.iec.ch).
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. In the IEC, see www.iec.ch/understanding-standards.
This document was prepared by Joint Technical Committee ISO/IEC JTC 1, Information technology,
Subcommittee SC 24, Computer graphics, image processing and environmental data representation.
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 and
www.iec.ch/national-committees.
iv
© ISO/IEC 2021 – All rights reserved

Introduction
Both virtual reality (VR) and mixed and augmented reality (MAR) employ virtual, synthetic and
computer-generated objects in their respective scenes, and they are rendered not only visually but in
other modalities in order to provide rich user experience based on realism, presence and augmentation.
VR and MAR applications are increasingly using haptic feedback to allow the user to interact physically
with the virtual or real objects and provide higher realism and elevated experience. That is, the input
from and output to the user may be delivered kinaesthetically (i.e. force feedback) through physical
simulation and the resulting force rendered through mechanical haptic devices. Note that the
interacting virtual or real object may be situated in virtual reality (VR), augmented reality (AR) and
augmented virtuality (AVR) – namely, across all types of MAR.
A correct and effective rendering of forces requires the relevant physical description of the materials
of the objects involved in the physical interaction and simulation. In addition, depending on the needs
of the application, different haptic rendering algorithms may be employed. Conventional standards for
virtual and mixed reality have lacked constructs for expressing such material properties or algorithmic
details and thereby supporting a comprehensive, faithful and flexible haptic rendering. For example,
most current standard 3D graphic or virtual object representations can only describe material
properties for visual rendering (e.g. for lighting effects and shading).
This document also provides definitions for terms related to material properties and physical
simulation in the context of the haptic rendering and its algorithms.
The target audience of this document are mainly VR and MAR system developers and content designers
interested in specifying and using haptic interaction. This document provides a basis for application
standards for any VR and MAR applications and content representation that uses haptic modality for
input and output.
However, this document establishes the information model. It does not promote or propose to use a
specific language, file format, algorithm, device, implementation method or standard. The model is
intended to be considered as the minimal basic model that can be extended for other purposes in actual
implementation.
The content of this document is derived from ISO/IEC 18039, which, among other things, specifies the
possible inclusion of haptic feedback (and associated devices) in experiential VR and MAR contents
1)
(and systems). The specification can be one important component in ISO/IEC 3721-1 , whose purpose
is to lay out and specify the information model for various essential MAR content components and their
relationships. While ISO/IEC 3721-1 lays the foundation and overall framework, it does not go into all
the details (e.g. material or haptic properties of an object). As haptic feedback may be used in purely
virtual environments as well, this document also relates to ISO/IEC 19775-1.
1) Under preparation. Stage at the time of publication: ISO/IEC DIS 3721-1:2021.
v
© ISO/IEC 2021 – All rights reserved

TECHNICAL SPECIFICATION ISO/IEC TS 23884:2021(E)
Information technology — Computer graphics, image
processing and environmental data representation —
Material property and parameter representation for
model-based haptic simulation of objects in virtual, mixed
and augmented reality (VR/MAR)
1 Scope
This document specifies:
— physical and material parameters of virtual or real objects expressed to support comprehensive
haptic rendering methods, such as stiffness, friction and micro-textures;
— a flexible specification of the haptic rendering algorithm itself.
It supplements other standards that describe scene or content description and information models for
virtual and mixed reality, such as ISO/IEC 19775 and ISO/IEC 3721-1.
2 Normative references
There are no normative references in this document.
3 Terms, definitions and abbreviated terms
3.1 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/
3.1.1
dynamic friction
friction that changes dynamically under certain external conditions
3.1.2
friction
tangential force emanating from the contact between two objects
3.1.3
haptic
kinaesthetic, force feedback and tactile feedback
3.1.4
haptic device
apparatus that delivers computer-simulated forces and torque to a human user for sensation, and also
receives input in the form of force and torque to be conveyed to the computer simulation of virtual and
mixed reality environment for emulating physical interaction
© ISO/IEC 2021 – All rights reserved

3.1.5
haptic modality
modality synonymous to the haptic sensation
3.1.6
haptic rendering
computing the amount of forces and torques occurring at the interaction point, based on the physical
simulation and interaction of the virtual and mixed reality world, and reflecting them to the user
through the haptic device
3.1.7
physical interaction
interaction, real or virtual, between a user and object(s) that involves the use of forces and torques via
contact
3.1.8
physical simulation
simulating the dynamic physical phenomena in the virtual and mixed reality environment based on the
environment description and given physical laws, and in the process, computing the relevant parameter
values, such as the amount of forces and torques
3.1.9
stiffness
rigidity of an object and the extent to which the object resists deformation in response to an applied
force
3.1.10
surface texture
micro surface texture
micro-scaled protrusion pattern on the surface of an object
3.2 Abbreviated terms
AR augmented reality
FFT fast Fourier transform
MAR mixed and augmented reality
VR virtual reality
4 Overview: Material properties for haptic simulation
4.1 General
Haptic rendering in the context of VR or MAR simulation refers to computing for the proper force or
torque to be exerted by the haptic device at a given point in the VR or MAR space (e.g. magnitude and
direction), see Figure 1.
© ISO/IEC 2021 – All rights reserved

a
Force.
b
Torque.
Figure 1 — Physical interaction with a virtual or real object (left) and using the haptic device to
obtain kinaesthetic feedback (right)
H3D API is an open-source, cross-platform, scene graph AI that has extended the X3D material and
[3]
surface node as “SmoothSurface,” “FrictionalSurface,” “DepthMapSurface” and “HapticTextureMap”
to express various haptic parameters directly.
For example, the declaration:

includes the linear stiffness of 1,0 and the damping factor of 0,5 for computing the resulting force as in
Formula (1):
Fk=+xvx′ (1)
where
x is the object displacement;
k is the stiffness factor;
v is the damping factor.
The following declaration is used for representing a “frictional” surface with added parameters such
as the static and dynamic friction constants. Consequently, the resulting
...