SIST EN ISO 22432:2012
(Main)Geometrical product specifications (GPS) - Features utilized in specification and verification (ISO 22432:2011)
Geometrical product specifications (GPS) - Features utilized in specification and verification (ISO 22432:2011)
ISO 22432:2011 defines general terms and types of features for geometrical features of specifications for workpieces. These definitions are based on concepts developed in ISO/TS 17450-1.
ISO 22432:2011 is not intended for industrial use as such among designers, but is aimed to serve as the "road map" mapping out the interrelationship between geometrical features, thus enabling future standardization for industry and software makers in a consistent manner.
Geometrische Produktspezifikation (GPS) - Zur Spezifikation und Prüfung benutzte Geometrieelemente (ISO 22432:2011)
Diese Internationale Norm legt die allgemeinen Begriffe und Merkmalstypen von (Geometrie) Elementen zur
technischen Beschreibung von Werkstücken fest. Diese Festlegungen beruhen auf den in der Norm
ISO/TS 17450-1 entwickelten Konzepten.
Es war nicht die Absicht, dass diese Internationale Norm als solche für die industrielle Anwendung unter
Konstrukteuren verwendet wird, sondern sie zielt vielmehr darauf ab, als ein Leitfaden zu dienen, der die
gegenseitige Beziehung zwischen (Geometrie) Elementen abbildet, um damit eine zukünftige
Standardisierung für die Industrie und für Programmierer in einer folgerichtigen Art und Weise zu ermöglichen.
Spécification géométrique des produits - Éléments utilisés en spécification et vérification (ISO 22432:2011)
L'ISO 22432:2011 définit les termes généraux et les types d'éléments pour les éléments géométriques des spécifications des pièces. Ces définitions s'appuient sur les concepts développés dans l'ISO/TS 17450‑1.
L'ISO 22432:2011 n'est pas destinée, en tant que telle, à un usage industriel par les concepteurs, mais vise à servir de fil d'Ariane pour l'élaboration des relations entre les éléments géométriques, permettant ainsi la future normalisation pour l'industrie et les concepteurs de logiciels de manière cohérente.
Specifikacija geometrijskih veličin izdelka - Značilnosti, potrebne za geometrijsko specifikacijo in preverjanje (ISO 22432:2011)
Ta mednarodni standard definira splošne izraze in vrste značilnosti za geometrijske značilnosti specifikacij za obdelovance. Te definicije temeljijo na konceptih, razvitih v ISO/TS 17450-1. Ta mednarodni standard naj se uporablja kot »zemljevid«, ki preslikuje medsebojne povezave med geometrijskimi značilnostmi in s tem dosledno omogoča prihodnjo standardizacijo za industrijo in izdelovalce programske opreme.
General Information
Standards Content (Sample)
SLOVENSKI STANDARD
01-januar-2012
6SHFLILNDFLMDJHRPHWULMVNLKYHOLþLQL]GHOND=QDþLOQRVWLSRWUHEQH]DJHRPHWULMVNR
VSHFLILNDFLMRLQSUHYHUMDQMH ,62
Geometrical product specifications (GPS) - Features utilized in specification and
verification (ISO 22432:2011)
Geometrische Produktspezifikation (GPS) - Zur Spezifikation und Prüfung benutzte
Geometrieelemente (ISO 22432:2011)
Spécification géométrique des produits - Éléments utilisés en spécification et vérification
(ISO 22432:2011)
Ta slovenski standard je istoveten z: EN ISO 22432:2011
ICS:
17.040.40 6SHFLILNDFLMDJHRPHWULMVNLK Geometrical Product
YHOLþLQL]GHOND *36 Specification (GPS)
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
EUROPEAN STANDARD
EN ISO 22432
NORME EUROPÉENNE
EUROPÄISCHE NORM
November 2011
ICS 17.040.01
English Version
Geometrical product specifications (GPS) - Features utilized in
specification and verification (ISO 22432:2011)
Spécification géométrique des produits (GPS) - Éléments Geometrische Produktspezifikation (GPS) - Zur
utilisés en spécification et vérification (ISO 22432:2011) Spezifikation und Prüfung benutzte Geometrieelemente
(ISO 22432:2011)
This European Standard was approved by CEN on 8 July 2011.
CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European
Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national
standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by translation
under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management Centre has the same
status as the official versions.
CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland,
Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2011 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 22432:2011: E
worldwide for CEN national Members.
Contents Page
Foreword .3
Foreword
This document (EN ISO 22432:2011) has been prepared by Technical Committee ISO/TC 213 "Dimensional
and geometrical product specifications and verification" in collaboration with Technical Committee
CEN/TC 290 “Dimensional and geometrical product specification and verification” the secretariat of which is
held by AFNOR.
This European Standard shall be given the status of a national standard, either by publication of an identical
text or by endorsement, at the latest by May 2012, and conflicting national standards shall be withdrawn at the
latest by May 2012.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. CEN [and/or CENELEC] shall not be held responsible for identifying any or all such patent rights.
According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following
countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech
Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia,
Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain,
Sweden, Switzerland and the United Kingdom.
Endorsement notice
The text of ISO 22432:2011 has been approved by CEN as a EN ISO 22432:2011 without any modification.
INTERNATIONAL ISO
STANDARD 22432
First edition
2011-11-15
Geometrical product specifications
(GPS) — Features utilized in specification
and verification
Spécification géométrique des produits (GPS) — Éléments utilisés en
spécification et vérification
Reference number
ISO 22432:2011(E)
©
ISO 2011
ISO 22432:2011(E)
© ISO 2011
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means,
electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or
ISO's member body in the country of the requester.
ISO copyright office
Case postale 56 CH-1211 Geneva 20
Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
E-mail copyright@iso.org
Web www.iso.org
Published in Switzerland
ii © ISO 2011 – All rights reserved
ISO 22432:2011(E)
Contents Page
Foreword . iv
Introduction . v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Relations between the geometrical feature terms . 35
Annex A (normative) Overview diagram . 39
Annex B (informative) Examples of links between the features . 45
Annex C (informative) Relation to the GPS matrix model . 48
Bibliography . 50
ISO 22432:2011(E)
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.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
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.
ISO 22432 was prepared by Technical Committee ISO/TC 213, Dimensional and geometrical product
specifications and verification.
iv © ISO 2011 – All rights reserved
ISO 22432:2011(E)
Introduction
This International Standard is a Geometrical Product Specifications (GPS) standard and is to be regarded as
a global GPS standard (see ISO/TR 14638). It influences all chain links in all chains of standards in the
general GPS matrix.
The ISO/GPS Masterplan given in ISO/TR 14638 gives an overview of the ISO/GPS system of which this
document is a part. The fundamental rules of ISO/GPS given in ISO 8015 apply to this document and the
default decision rules given in ISO 14253-1 apply to specifications made in accordance with this document,
unless otherwise indicated.
Geometrical features exist in three “worlds”:
the world of nominal definition, where an ideal representation of the workpiece is defined by the designer;
the world of specification, where the designer has in mind several representations of the workpiece;
the world of verification, where one (or more) representation(s) of a given workpiece is (are) identified in
the application of measuring procedure(s).
In the world of verification, mathematical operations can be distinguished from physical operations. The
physical operations are the operations based on physical procedures; they are generally mechanical, optical
or electromagnetic. The mathematical operations are mathematical treatments of the sampling of the
workpiece. This treatment is generally achieved by computing or electronic treatment.
It is important to understand the relationship between these three worlds. This International Standard defines
standardized terminology for geometrical features principally in the world of specification and the world of
verification, to be used in communication between each world.
The features defined in this International Standard are well suited for the specification of rigid parts and
assemblies, and may also be applied to non-rigid parts and assemblies by specifying allowable variation
according to rigid solids.
INTERNATIONAL STANDARD ISO 22432:2011(E)
Geometrical product specifications (GPS) — Features utilized in
specification and verification
1 Scope
This International Standard defines general terms and types of features for geometrical features of
specifications for workpieces. These definitions are based on concepts developed in ISO/TS 17450-1.
This International Standard aims to serve as the “road map” mapping out the interrelationship between
geometrical features, thus enabling future standardization for industry and software makers in a consistent
manner.
2 Normative references
The following referenced documents are indispensable for the application 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 14660-1:1999, Geometrical Product Specifications (GPS) — Geometrical features — Part 1: General
terms and definitions
ISO/TS 17450-1:2005, Geometrical product specifications (GPS) — General concepts — Part 1: Model for
geometrical specification and verification
ISO/TS 17450-2:2002, Geometrical product specifications (GPS) — General concepts — Part 2: Basic tenets,
specifications, operators and uncertainties
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 14660-1, ISO/TS 17450-1 and
ISO/TS 17450-2 and the following apply.
3.1
surface model
model representing the set of features limiting the virtual or the real workpiece
NOTE 1 All closed surfaces (see Figures 1 and A.1) are included.
NOTE 2 The surface model allows the definition of single features, sets of features, and/or portions of features. The
total product is modelled by a set of surface models corresponding to each workpiece.
EXAMPLE Case of a hollow surface.
ISO 22432:2011(E)
a
Representation of a real surface of the workpiece
Representation of the real workpiece
Representation of nominal Representation of skin Representation of discrete Representation of sampled
surface model model surface model surface model
a
For the purpose of this International Standard.
NOTE It is impossible to predict the total geometry of the real workpiece due to its geometrical imperfections. In this
International Standard, a real surface of the workpiece is illustrated in solid black.
Figure 1 — Example of real surface of the workpiece and its models
3.1.1
nominal surface model
surface model of ideal geometry defined by the technical product documentation
NOTE 1 A nominal surface model is an ideal feature (See Figure 1 and Table 1).
NOTE 2 A nominal surface model is a continuous surface composed of an infinite number of points.
NOTE 3 Any feature on the nominal surface model (skin model) contains a continuous infinite number of points.
3.1.2
skin model
surface model of non-ideal geometry
NOTE 1 The skin model is a virtual model used to express the specification operator and the verification operator
considering a continuous surface (see Table 1 and ISO/TS 17450-1).
NOTE 2 A skin model is a non-ideal feature (see Figure 1).
NOTE 3 A skin model is a continuous surface consisting of an infinite number of points.
NOTE 4 Any feature on the skin model contains a continuous infinite number of points.
2 © ISO 2011 – All rights reserved
ISO 22432:2011(E)
3.1.3
discrete surface model
surface model obtained from the skin model by an extraction
NOTE 1 In addition to the required points, the extraction implies an interpolation.
NOTE 2 The discrete surface model is used to express the specification operator and the verification operator
considering a finite number of points (see Table 1).
NOTE 3 A discrete surface model is a non-ideal feature (see Figure 1).
3.1.4
sampled surface model
surface model obtained from the real workpiece model by a physical extraction
NOTE 1 In addition to the sampled points, the verification may imply an interpolation.
NOTE 2 The sampled surface model is used in verification by coordinate metrology, not, for example, in verification by
a gauge because gauging makes no measurement of points. In verification by a gauge, the real surface of the workpiece
is directly considered (see Table 1).
NOTE 3 A sampled surface model is a non-ideal feature (see Figure 1).
3.2
geometrical feature
point, line, surface, volume or a set of these previous items
NOTE 1 The non-ideal surface model is a particular geometrical feature, corresponding to the infinite set of points
defining the interface between the workpiece and the surrounding.
NOTE 2 A geometrical feature can be an ideal feature or a non-ideal feature, and can be considered as a single
feature or a compound feature.
3.2.1
nominal feature
geometrical feature of ideal geometry defined in the technical product documentation by the product designer
NOTE 1 See Figure B.1.
NOTE 2 A nominal feature is defined by the technical product documentation. See Table 1.
NOTE 3 A nominal feature can be finite or infinite; by default it is infinite.
EXAMPLE A perfect cylinder, defined in a drawing, is a nominal feature obeying a specific mathematical formula,
which is defined in a coordinate system related to the situation feature, and for which dimensional parameters are
associated. The situation feature of a cylinder is a line which is commonly called “its axis”. Taking this line as an axis of a
2 2
Cartesian coordinate system leads to writing x y D/2, D being a dimensional parameter. A cylinder is a feature of size,
of which the size is its diameter D.
3.2.2
real feature
geometrical feature corresponding to a part of the workpiece real surface
3.2.3
discrete feature
geometrical feature corresponding to a part of the discrete surface model
3.2.4
sampled feature
geometrical feature corresponding to a part of the sampled surface model
ISO 22432:2011(E)
3.2.5
ideal feature
feature defined by a parameterized equation
[ISO/TS 17450-1:2005, definition 3.13]
NOTE 1 The expression of the parameterized equation depends on the type of ideal feature and on the intrinsic
characteristics.
NOTE 2 By default, an ideal feature is infinite. To change its nature, it is appropriate to specify it by the term “restricted”,
e.g. restricted ideal feature.
NOTE 3 For a complex surface defined by a cloud of points and an interpolation method, the cloud of points is
considered the parameter.
NOTE 4 This definition is also contained in ISO/TS 17450-1:2005. It is envisaged that it will be deleted from
ISO 17450-1:2011.
3.2.5.1
attribute of an ideal feature
property intrinsically attached to an ideal feature
NOTE 1 Four levels of attributes can be defined for an ideal feature: shape, dimensional parameters from which a size
can be defined in the case of a feature of size, situation feature and skeleton (when the size tends to zero).
NOTE 2 If the ideal feature is a feature of size, then one of the parameters of the shape can be considered as a size.
3.2.5.1.1
feature of size
geometrical feature having one or more intrinsic characteristics, only one of which may be considered as a
variable parameter, that additionally is a member of a “one-parameter family”, and obey the monotonic
containment property, for that parameter
NOTE 1 A feature of size can be a sphere, a circle, two straight lines, two parallel opposite planes, a cylinder, a torus,
etc. In former International Standards a wedge and a cone were considered as features of size, and a torus was not
mentioned.
NOTE 2 There are restrictions when there is more than one intrinsic characteristic (e.g. a torus).
NOTE 3 Relative to the function, a feature of size is particularly useful for the expression of material requirements
(LMR and MMR, see ISO 2692).
EXAMPLE 1 A single cylinder constituting a hole or a shaft is a feature of size. Its size is its diameter.
EXAMPLE 2 A compound feature of two single parallel plans constituting a groove or a key is a feature of size. Its size
is its width.
3.2.5.1.1.1
one-parameter family
set of ideal geometrical features defined by one or more dimensional parameters whose members are
generated by varying one parameter
EXAMPLE 1 A set of o-rings (torus-shaped) with the same fixed median-ring diameter and different cross-sectional
diameters is a one-parameter family (see Figure 2).
EXAMPLE 2 A set of gauge blocks defined by the gauge blocks' thickness is a one-parameter family.
4 © ISO 2011 – All rights reserved
ISO 22432:2011(E)
Key
D median-ring diameter
d cross-sectional diameter
Figure 2 — Example of one-parameter family
3.2.5.1.1.2
monotonic containment property
property of a one-parameter family where a member with a given size contains any member with a smaller
size
EXAMPLE 1 A torus belonging to a one-parameter family, corresponding to a set of o-rings (torus-shaped) with the
same fixed median-ring diameter and different cross-sectional diameters, respects the monotonic containment property,
because from an ideal point of view, the larger family member completely envelopes the smaller family member (see
Figure 3).
EXAMPLE 2 A torus belonging to a one-parameter family, corresponding to a set of o-rings (torus-shaped) with
different median-ring diameters and the same fixed cross-sectional diameter, does not respect the monotonic containment
property and therefore cannot be considered as a feature of size.
Figure 3 — Monotonic containment property
3.2.5.1.2
situation feature
geometrical feature defining the location or orientation of an ideal feature and which is a geometrical attribute
of the ideal feature
See Figures 4 to 7.
ISO 22432:2011(E)
a) Pair of parallel planes b) Cone c) Two non-parallel planes
Figure 4 — Example of situation planes
a) Axis of a cylinder b) Axis of a cone
Figure 5 — Example of situation lines
a) Situation point of a cone b) Situation point of a sphere
Figure 6 — Example of situation points
6 © ISO 2011 – All rights reserved
ISO 22432:2011(E)
Figure 7 — Example of situation helix
NOTE In many cases, instead of using the situation helix, the axis of the situation helix is used.
3.2.5.2
shape of an ideal feature
mathematical generic description defining the ideal geometry of a feature
NOTE An ideal feature of a preset shape can be qualified or named.
EXAMPLE 1 Planar shape, cylindrical shape, spherical shape, conical shape.
EXAMPLE 2 A surface can be qualified “planar surface” or be directly named “plane”.
3.2.5.3
skeleton feature
reduction of an ideal feature when its size is equal to zero
NOTE In some cases, the skeleton feature is identical to the situation feature. In the case of the cylinder, the skeleton
feature is identical to the situation feature, which is not the case for the torus.
EXAMPLE In the case of a torus, there are two dimensional parameters of which one is a size (the cross-sectional
diameter of the torus). Its skeleton is a circle and its situation features are its plane and a perpendicular line.
3.2.6
non-ideal feature
imperfect feature fully dependent on the non-ideal surface model (skin model)
[ISO/TS 17450-1:2005, definition 3.19]
NOTE 1 A non-ideal feature is, by default, of finite dimension. To change this nature, it is appropriate to specify it by
associating the restricted term.
NOTE 2 This definition is also contained in ISO/TS 17450-1:2005. It is envisaged that it will be deleted from
ISO 17450-1:2011.
3.2.7
specification feature
geometrical feature identified from the skin model or from the discrete surface model and defined by the
specification operator
See Table 1 and Figure B.2.
NOTE Specification and verification operators are defined in ISO/TS 17450-2.
EXAMPLE 1 In the process of specification, an ideal cylinder identified from the skin model by an association is an
ideal specification feature.
ISO 22432:2011(E)
EXAMPLE 2 In the process of specification, a non-ideal cylindrical surface identified from the skin model by a partition
is a non-ideal specification feature.
3.2.8
verification feature
geometrical feature (identified from the skin model, the discrete surface model or the sampled surface model)
or real feature defined by the verification operator
See Table 1 and Figure B.3
NOTE 1 In the world of verification, mathematical operations can be distinguished from physical operations. These
physical operations are based on physical procedures; they are generally mechanical, optical or electromagnetic. The
complete specification operator includes the type of physical property to which the specification applies.
NOTE 2 The geometrical feature identified from the skin model or from the discrete surface model is used to define the
verification operator. The geometrical feature identified from the sampled surface model and the real feature are used to
implement the verification operator.
EXAMPLE 1 In the process of verification, a perfect cylinder identified from the workpiece by an association is an ideal
verification feature.
EXAMPLE 2 In the process of verification, an imperfect cylindrical surface identified from the workpiece by a partition
is a non-ideal verification feature.
Table 1 — Use of surface models
Surface model
Field of use Real surface
Nominal Skin Discrete Sampled
surface model model surface model surface model
Technical product documentation Applicable Non-applicable Non-applicable Non-applicable Non-applicable
Specification operator Non-applicable Applicable Applicable Non-applicable Non-applicable
Verification operator Non-applicable Applicable Applicable Applicable Applicable
3.2.9
single feature
geometrical feature which is a single point, a single line, or a single surface
NOTE A single feature can have none, or one or more intrinsic characteristics, e.g.:
a plane is a single feature but has no intrinsic characteristic;
a cylinder has only one intrinsic characteristic;
a torus has two intrinsic characteristics.
EXAMPLE A cylinder is a single feature (see Figures 8 and 9). A set of surfaces made up of two intersecting planes
is not a single feature, because one plane has a greater invariance degree than two planes (see 3.2.9.4, Note 3).
8 © ISO 2011 – All rights reserved
ISO 22432:2011(E)
Nominal feature Specification feature Verification feature
Single integral
features
Single associated
features
Single feature
portions
Obtained from
Nominal surface Discrete surface Sampled surface Real surface of a
Skin model
model model model workpiece
Key
1 single integral features 3 single feature portions
2 single associated features 4 single nominal features
Figure 8 — Examples of single features built from the same nominal plane
ISO 22432:2011(E)
Nominal feature Specification feature Verification feature
Example of a
single nominally
planar feature
Example of a
single nominally
cylindrical feature
Example of a
single-portion
nominally planar
feature
Example of a
feature pair on a
nominally
cylindrical
surface
Obtained from
Nominal surface Discrete surface Sampled surface Real surface of a
Skin model
model model model workpiece
Figure 9 — Examples of single features built from different surface models
10 © ISO 2011 – All rights reserved
ISO 22432:2011(E)
3.2.9.1
single point
point taken from a single surface or from a single line
3.2.9.2
single line
continuous line which is nominally a straight line, a circle or a complex line
NOTE 1 An arc is a restricted circle (see Figure 10).
NOTE 2 A single line does not intersect itself.
Figure 10 — Example of single lines
3.2.9.3
complex line
continuous line that is not a straight line or a circular line of which the shape and the extension are defined
and indicated by the designer in respect of the writing rules
3.2.9.4
single surface
continuous surface which is nominally a plane, a cylinder, a sphere, a cone, a torus, another surface of
revolute invariance class, a surface of prismatic invariance class, a helix, a surface of complex invariance
class, or a restricted part of one of them
NOTE 1 A revolute surface is a single surface if its generatrix is a single line (see Figure 11).
NOTE 2 Table 1 of ISO/TS 17450-1:2005 illustrates the types of single surfaces with their invariance degree.
NOTE 3 If a surface contains a surface portion of higher invariance degree than itself then it is not a single surface. A
partial ordering of single-surface types, based on whether they can contain each other, is given in Figure 12. The ordering
is partial because some surface types cannot be contained within each other.
Figure 11 — Example of single surfaces
ISO 22432:2011(E)
Complex
Helix Revolute Prism
Torus
Cylinder
Cone
Sphere
Plane
Figure 12 — Partial ordering of single-surface types
3.2.9.5
complex surface
continuous surface of which the shape and the extension are defined and indicated by the designer in respect
of the writing rules, and is not considered a plane, cylinder, cone, torus or sphere
3.2.10
compound feature
geometrical feature which is a collection of several single features
NOTE 1 A compound feature can have none, or one or more intrinsic characteristics. For instance, the set of two
parallel planes is a compound feature, which has one intrinsic characteristic.
NOTE 2 The number of features constituting a compound feature can be finite (countable) or infinite (continuous) in
number (see Figure 13).
EXAMPLE 1 A set of surfaces consisting of two parallel cylinders is a compound feature (see Figure 14).
EXAMPLE 2 A geometrical feature made up from two groups of two parallel planes is a compound feature.
12 © ISO 2011 – All rights reserved
ISO 22432:2011(E)
Nominal feature Specification feature Verification feature
Example of a
compound feature
consisting of a
finite number of
single-portion
nominally planar
features
Example of a
compound feature
consisting of an
infinite number of
single nominally
straight lines
Obtained from
Nominal surface Discrete surface Sampled surface Real surface of a
Skin model
model model model workpiece
Figure 13 — Example of compound feature built from a finite or infinite number of single features
ISO 22432:2011(E)
Nominal feature Specification feature Verification feature
Example of a
compound feature
consisting of two
nominally planar
surfaces
Example of a
compound feature
consisting of two
nominally
cylindrical
surfaces
Example of
compound feature
consisting of a
finite number of
point pairs
Obtained from
Nominal surface Discrete surface Sampled surface Real surface of a
Skin model
model model model workpiece
Figure 14 — Examples of compound features
3.2.11
extracted feature
geometrical feature consisting of a finite number of points
NOTE 1 When the representation is defined by an infinite number of points, the word “extracted” is not used with the
considered terms.
EXAMPLE An integral feature is, by default, an infinite representation, whereas an integral feature is extracted with a
finite representation.
NOTE 2 The concept of “extracted” can apply to an integral feature or a derived feature.
3.2.12
infinite feature
geometrical feature consisting of an infinite number of points
14 © ISO 2011 – All rights reserved
ISO 22432:2011(E)
3.2.13
complete feature
total feature
geometrical feature containing the totality of the points corresponding to one or more single geometrical
features and pertaining to the surface model
3.2.14
restricted feature
geometrical feature corresponding to a portion of a complete/total non-ideal feature or having a portion of an
(ideal) infinite feature
3.3
integral feature
surface or line on a surface
[ISO 14660-1:1999, definition 2.1.1]
NOTE 1 An integral feature is intrinsically defined.
NOTE 2 For the statement of specifications, features obtained from partition of the surface model must be defined.
These features are models of the different physical parts of the workpiece that have specific functions, especially contact
with the adjacent workpieces. These features are called “integral features”.
NOTE 3 The integral feature is either a single or compound feature (see Figures 14 and A.3).
NOTE 4 An integral feature is identified either
by a partition of the surface model, or
by a partition of another integral feature, or
by a collection of other integral features.
Nominal feature Specification feature Verification feature
Example of an
integral single
nominally planar
feature
Example of an
integral compound
feature
Obtained from
Nominal surface Discrete surface Sampled surface Real surface of a
Skin model
model model model workpiece
Figure 15 — Example of integral features
ISO 22432:2011(E)
3.3.1
integral surface portion
integral surface which is a portion of the complete surface
NOTE An integral surface portion is obtained from any type of section volume (see Figure 16).
3.3.2
integral line portion
integral line which is a portion of the complete line
NOTE An integral line portion is obtained from a defined section volume, e.g. by two parallel planes (see Figure 16).
Nominal feature Specification feature Verification feature
Example of
restricted integral
surface obtained
by a rectangular
section volume
Example of
restricted integral
surface obtained
by a cylindrical
section volume
Example of
restricted line; the
section volume is
limited by two
parallel planes
Obtained from
Nominal surface Discrete surface Sampled surface Real surface of a
Skin model
model model model workpiece
Figure 16 — Example of restricted feature
3.3.3
coupled feature
surface pair, line pair and point pair
NOTE A coupled feature is a special collection of ideal or non-ideal features which are obtained together in a partition
(see Figure 17).
16 © ISO 2011 – All rights reserved
ISO 22432:2011(E)
Nominal feature Specification feature Verification feature
Example of point
pair
Example of
compound feature
of finite set of point
pairs
Example of
surface pair
corresponding to
nominally parallel
planes
Example of line
pair corresponding
to two nominally
parallel circles
Obtained from
Nominal surface Discrete surface Sampled surface Real surface of a
Skin model
model model model workpiece
Figure 17 — Examples of coupled features
3.3.3.1
surface pair
set of at least two surfaces obtained from partition of a geometrical feature by a section volume
3.3.3.2
line pair
set of at least two lines obtained from partition of a geometrical feature by a section surface
3.3.3.3
point pair
set of at least two points obtained from partition of a geometrical feature by a section line
NOTE To define a point pair, the section line is often taken perpendicular to an ideal median-considered feature.
ISO 22432:2011(E)
3.4
filtered feature
non-ideal feature which is the result of a filtration of a non-ideal feature
See Figures 18 and A.5.
NOTE 1 The filtered feature is a specification or verification filtered feature, depending on the model from which it is
defined. Nominal filtered features do not exist.
NOTE 2 Relating to the function, the features considered are often not directly integral features, but integral features
after a filtration.
NOTE 3 To describe a filter, it is sometimes necessary to use other types of features, for example associated features,
offset features, enabling features (section features, structuring features).
Key
1 non-ideal feature before filtration
2 filtered feature (non-ideal feature after filtration)
Figure 18 — Specification and verification filtered features
EXAMPLE 1 Creation of the roughness profile by applying a longwave cut-off filter to remove long wavelengths and
form from the primary profile. The roughness profile is one of the family of filtered features. The primary profile is one of
the family of integral features (see Figure 19).
Primary profile Filter Roughness profile
Integral feature Filter Filtered feature
Figure 19 — Example of creation of roughness profile
EXAMPLE 2 Roundness profile resulting from applying a Gaussian longwave-pass filter to the extracted
circumferential line: the roundness profile belongs to the family of filtered features. The extracted circumferential line
belongs to the family of integral features (see Figure 18).
3.4.1
filtered surface
surface which is the result of a filtration of a surface
3.4.2
filtered line
line which is the result of a filtration of a line
3.5
derived feature
geometrical feature, which is a median, displaced, congruent or reflected feature resulting from a set of
operations on an integral or filtered feature
18 © ISO 2011 – All rights reserved
ISO 22432:2011(E)
NOTE 1 The set of operations either preserve the nature of the original feature in such a way that the derived feature
has the appearance of the original feature or convert the nature of the original feature in such a way that the derived
feature becomes the median feature of the original feature (see Figure 20).
NOTE 2 A derived feature is non-ideal when it is obtained from a non-ideal feature. It is ideal when it is obtained from
an ideal feature.
NOTE 3 The derived feature is a nominal, specification or verification derived feature, depending on the model from
which it is defined.
NOTE 4 The derived feature can be established from a nominal feature, associated feature, or non-ideal feature.
NOTE 5 Integral features and filtered features are used in specifications, as well as features identified from them, such
as displaced features and median features (see Figure 21).
EXAMPLE The axis of a nominal cylinder is a nominal derived feature.
Nominal feature Specification feature Verification feature
Example of a
derived feature
which is nominally
the axis of a
cylinder (case of
median feature)
Example of a
derived feature
which is offset
from the single
feature to x mm
(case of offset
feature)
Obtained from
Nominal surface Discrete surface Sampled surface Real surface of a
Skin model
model model model workpiece
Key
1 derived feature
2 offset of the derived feature
Figure 20 — Example of derived features
ISO 22432:2011(E)
Key
1 nominal integral feature 3 nominal offset feature 5 nominal translated feature
2 nominal median feature 4 nominal rotated feature 6 nominal reflected feature
Figure 21 — Illustration of nominal derived feature shown in 2D
3.5.1
median feature
median point, ideal or non-ideal median line or median surface
NOTE 1 A median feature is defined by the construction of a collection of points.
NOTE 2 A median feature is not an integral feature.
NOTE 3 The type of median feature relative to the real workpiece is not necessarily the same as the nominal median
feature (see Figure 22). For example:
a median feature, which is nominally a line, may be seen on the workpiece as a line or a surface;
a median feature, which is nominally a point, may be seen on the workpiece as a point, a line or a surface.
NOTE 4 Median features are defined from “local symmetry centres”. They are defined in order to specify permissible
deviations on symmetry features.
NOTE 5 A median feature is not always a situation feature (e.g. the median feature of a torus, which is not the “line and
point” situation feature).
NOTE 6 A median feature can be ideal or non-ideal.
Key
1 nominal integral line 3 non-ideal integral line 5 associated line
2 nominal median point 4 non-ideal median line (each point of 6 directly associated median point
the median line is defined as the centre of
the two opposite points)
Figure 22 — Example of type changing related to a median feature
20 © ISO 2011 – All rights reserved
ISO 22432:2011(E)
3.5.1.1
median surface
nominal median surface, non-ideal median surface, indirectly associated median surface or directly associated
median surface
See Figure 23.
3.5.1.1.1
nominal median surface
surface consisting of a set of an infinite number of centres of the point pairs of the nominal integral surface(s)
See Figure 23.
3.5.1.1.2
non-ideal median surface
surface consisting of a set of an infinite number of centres of the point pairs of the non-ideal integral or filtered
surface(s)
See Figure 23.
3.5.1.1.3
indirectly associated median surface
substitute feature of the non-ideal median surface
See Figure 23.
3.5.1.1.4
directly associated median surface
surface consisting of a set of an infinite number of centres of the point pairs of the substitute surface(s)
See Figure 23.
ISO 22432:2011(E)
Nominal feature Specification feature Verification feature
Example of median
surface of a
compound feature
corresponding
nominally to a pair
of planes, that is
two parallel planes
Obtained from
Nominal surface Skin model Discrete surface Sampled surface Real surface of a
model model model workpiece
Key
1 nominal pair of surfaces
2 nominal median surface
3 non-ideal pair of surfaces
4 non-ideal median surface
5 indirectly associated median surface
6 substitute surface
Figure 23 — Example of median surfaces
22 © ISO 2011 – All rights reserved
ISO 22432:2011(E)
3.5.1.2
median line
nominal median line, non-ideal median line, indirectly associated median line or directly associated median
line
See Figure 24.
3.5.1.2.1
nominal median line
line consisting of a set of an infinite number of section centres or centres of point pairs of the nominal integral
surface(s) or line(s)
See Figure 24.
3.5.1.2.2
non-ideal median line
line consisting of a set of an infinite number of section centres or centres of point pairs of the non-ideal integral
or filtered surface(s) or line(s)
See Figure 24.
3.5.1.2.3
indirectly associated median line
substitute feature of the non-ideal median line
NOTE When an indirectly or directly associated median line is not to be considered as infinite, it is necessary to
qualify it as an indirectly or directly associated median-line portion.
See Figure 24.
3.5.1.2.4
directly associated median line
situation feature or feature portion of the substitute feature, of the integral or filtered surface(s) or line(s)
NOTE Line consisting of a set of an infinite number of section centres.
See Figure 24.
ISO 22432:2011(E)
Nominal feature Specification feature Verification feature
Example of a
median line, which
is nominally the
axis of a cylinder
Obtained from
Nominal surface Discrete surface Sampled surface Real surface of a
Skin model
model model model workpiece
Key
1 nominal integral surface
2 nominal median line
3 non-ideal integral surface
4 non-ideal median line
5 indirectly associated median line (substitute line)
6 directly associated integral surface (substitute surface)
7 directly associated median line
Figure 24 — Example of median lines
24 © ISO 2011 – All rights reserved
ISO 22432:2011(E)
3.5
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