EN ISO 1660:2017

SLOVENSKI STANDARD
01-april-2017
1DGRPHãþD
SIST EN ISO 1660:2000
6SHFLILNDFLMDJHRPHWULMVNLKYHOLþLQL]GHOND*367ROHULUDQMHJHRPHWULMVNLKYHOLþLQ
7ROHULUDQMHSURILORY,62
Geometrical product specifications (GPS) - Geometrical tolerancing - Profile tolerancing
(ISO 1660:2017)
Geometrische Produktspezifikation (GPS) - Geometrische Tolerierung - Profiltolerierung
(ISO 1660:2017)
Spécification géométrique des produits (GPS) - Tolérancement géométrique -
Tolérancement des profils (ISO 1660:2017)
Ta slovenski standard je istoveten z: EN ISO 1660:2017
ICS:
01.100.01 7HKQLþQRULVDQMHQDVSORãQR Technical drawings in
general
17.040.10 Tolerance in ujemi Limits and fits
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.

EN ISO 1660
EUROPEAN STANDARD
NORME EUROPÉENNE
February 2017
EUROPÄISCHE NORM
ICS 01.100.01; 17.040.40 Supersedes EN ISO 1660:1995
English Version
Geometrical product specifications (GPS) - Geometrical
tolerancing - Profile tolerancing (ISO 1660:2017)
Spécification géométrique des produits (GPS) - Geometrische Produktspezifikation (GPS) -
Tolérancement géométrique - Tolérancement des Geometrische Tolerierung - Profiltolerierung (ISO
profils (ISO 1660:2017) 1660:2017)
This European Standard was approved by CEN on 14 December 2016.

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, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,
Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Turkey and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2017 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 1660:2017 E
worldwide for CEN national Members.

Contents Page
European foreword . 3

European foreword
This document (EN ISO 1660:2017) 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 August 2017 and conflicting national standards shall
be withdrawn at the latest by August 2017.
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.
This document supersedes EN ISO 1660:1995.
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, Former Yugoslav Republic of Macedonia, France,
Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands,
Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and
the United Kingdom.
Endorsement notice
The text of ISO 1660:2017 has been approved by CEN as EN ISO 1660:2017 without any modification.
INTERNATIONAL ISO
STANDARD 1660
Third edition
2017-02
Geometrical product specifications
(GPS) — Geometrical tolerancing —
Profile tolerancing
Spécification géométrique des produits (GPS) — Tolérancement
géométrique — Tolérancement des profils
Reference number
ISO 1660:2017(E)
©
ISO 2017
ISO 1660:2017(E)
© ISO 2017, Published in Switzerland
All rights reserved. Unless otherwise specified, 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
Ch. de Blandonnet 8 • CP 401
CH-1214 Vernier, Geneva, Switzerland
Tel. +41 22 749 01 11
Fax +41 22 749 09 47
copyright@iso.org
www.iso.org
ii © ISO 2017 – All rights reserved

ISO 1660:2017(E)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Symbols . 2
5 Rules for profile tolerancing . 3
5.1 General . 3
5.2 Default rules for profile tolerancing . 4
5.2.1 Rule A: Definition of the theoretically exact feature (TEF) . 4
5.2.2 Rule B: Type of toleranced feature . 5
5.2.3 Rule C: Definition of the tolerance zone . 5
5.3 Rules for profile tolerancing using additional specification elements . 7
5.3.1 Rule D: Toleranced feature specification elements . 7
5.3.2 Rule E: Unequally disposed tolerance zone . 8
5.3.3 Rule F: Linear tolerance zone offset . 8
5.3.4 Rule G: Angular tolerance zone offset . 8
5.3.5 Rule H: Variable tolerance zone width . 8
5.3.6 Rule I: Filtered feature specification elements . 8
5.3.7 Rule J: Association and parameter specification elements . 9
5.3.8 Rule K: Associated toleranced feature specification elements . . 9
5.3.9 Rule L: Non-rigid part . 9
Annex A (informative) Compound features .10
Annex B (informative) Illustration of the rules .12
Annex C (informative) Former practices .42
Annex D (informative) Relation to the GPS matrix model .44
Bibliography .45
ISO 1660:2017(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.
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 on 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 the following URL: www . i so .org/ iso/ foreword .html.
This document was prepared by Technical Committee ISO/TC 213, Dimensional and geometrical product
specifications and verification.
This third edition cancels and replaces the second edition (ISO 1660:1987), which has been technically
revised with the following changes:
— the requirements for defining the theoretically exact feature (the nominal geometry) have been
made more explicit;
— the definition of what constitutes the toleranced feature has been clarified and updated to follow
the feature principle, (see ISO 8015:2011, 5.5);
— tools for defining specifications for restricted features and compound features have been added;
— tools for defining specifications using unequally disposed or offset tolerance zones have been added;
— tools for defining specifications using tolerance zone of variable width have been added.
iv © ISO 2017 – All rights reserved

ISO 1660:2017(E)
Introduction
This document is a geometrical product specification (GPS) standard and is to be regarded as a general
GPS standard (see ISO 14638). It influences the chain links A, B and C of the chains of standards on
form, orientation and location.
The ISO GPS Masterplan given in ISO 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.
For more detailed information of the relation of this document to the GPS matrix model, see Annex D.
This document provides rules for profile tolerancing.
For the presentation of lettering (proportions and dimensions), see ISO 3098-2.
All figures in this document for the 2D drawing indications have been drawn in first-angle projection
with dimensions and tolerances in millimetres. It should be understood that third-angle projection
and other units of measurement could have been used equally well without prejudice to the principles
established. For all figures giving specification examples in 3D, the dimensions and tolerances are the
same as for the similar figures shown in 2D.
The figures in this document represent either 2D drawing views or 3D axonometric views on 2D
drawings and are intended to illustrate how a specification can be fully indicated with visible
annotation. For possibilities of illustrating a specification, where elements of the specification may be
available through a query function or other interrogation of information in the 3D CAD model and rules
for attaching specifications to 3D CAD models, see ISO 16792.
The figures in this document illustrate the text and are not intended to reflect an actual application.
Consequently, the figures are not fully dimensioned and specified, showing only the relevant general
principles. Neither are the figures intended to imply a particular display requirement in terms of
whether hidden detail, tangent lines or other annotations are shown or not shown. Many figures have
lines or details removed for clarity, or added or extended to assist with the illustration of the text. See
Table 1 for the line types used in definition figures.
In order for a GPS specification to be unambiguous, the partition defining the boundary of the toleranced
feature, as well as the filtering should be well defined. Currently, the detailed rules for partitioning and
the default for filtering are not defined in GPS standards.
For a definitive presentation (proportions and dimensions) of symbols for geometrical tolerancing, see
ISO 7083 and ISO 1101:2017, Annex F.
For the purposes of this document, the terms “axis” and “median plane” are used for derived features
of perfect form, and the terms “median line” and “median surface” for derived features of imperfect
form. Furthermore, the following line types have been used in the explanatory illustrations, i.e. those
representing non-technical drawings for which the rules of ISO 128 (all parts) apply.
ISO 1660:2017(E)
Table 1
Line type
Feature level Feature type Details
Visible Behind plane/
surface
point
integral feature line/axis wide continuous narrow dashed
surface/plane
Nominal feature
point
narrow long dashed narrow dashed
derived feature line/axis
dotted dotted
surface/plane
surface wide freehand narrow freehand
Real feature integral feature
continuous dashed
point
integral feature line wide short dashed narrow short dashed
surface
Extracted feature
point
derived feature line wide dotted narrow dotted
surface
line
Filtered feature integral feature continuous narrow continuous narrow
surface
point narrow double-
wide doubled-dashed
integral feature straight line dashed double-
double-dotted
plane dotted
point
narrow long dashed wide dashed
Associated feature derived feature straight line (axis)
double-dotted double-dotted
plane
point
wide long dashed narrow long dashed
datum line/axis
double-short dashed double-short dashed
surface/plane
Tolerance zone lim- line
continuous narrow narrow dashed
its, tolerance planes surface
Section, illustration line
narrow long dashed narrow dashed
plane, drawing plane, surface
short dashed short dashed
aid plane
Extension, dimen- line
sion, leader and continuous narrow narrow dashed
reference lines
Contrary to other kinds of geometrical tolerancing, profile tolerancing also allows geometrical
tolerancing of non-straight lines and non-flat surfaces, in addition to simpler features, such as planes,
cylinders, etc. This makes profile tolerancing more complex than other geometrical tolerancing
with respect to the definition of the nominal geometry and the extent of the toleranced feature. This
document expands on and provides tools and rules for these two complexities.
This edition of ISO 1660 is a pilot project for writing rule-based standards for geometrical tolerancing
rather than example-based standards. In the long term, it is envisioned that the content of this document
will be integrated into a future rule-based ISO 1101.
vi © ISO 2017 – All rights reserved

ISO 1660:2017(E)
This document references other standards for rules for GPS tolerancing in general and geometrical
tolerancing in particular, rather than repeating those rules. These GPS principles and rules include, but
are not limited to:
— the feature principle (see ISO 8015:2011, 5.4);
— the independency principle (see ISO 8015:2011, 5.5);
— the rules for implicit TEDs (see ISO 5458:1998, 4.3);
— the width of the tolerance zone applies normal to the toleranced feature (See ISO 1101:2017,
Clause 7);
— the rules for identifying the toleranced features (see ISO 1101:2017, Clause 6 and 9.1);
— form specifications, i.e. specifications without reference to a datum, a datum system or a pattern,
constrain neither orientation nor location (see ISO 1101:2017, 4.8);
— the tolerance zone can be constrained by reference to datums (see ISO 5459).
INTERNATIONAL STANDARD ISO 1660:2017(E)
Geometrical product specifications (GPS) — Geometrical
tolerancing — Profile tolerancing
IMPORTANT — The illustrations included in this document are intended to illustrate the text
and/or to provide examples of the related technical drawing specification; these illustrations are
not fully dimensioned and toleranced, showing only the relevant general principles. In particular,
the illustrations do not contain filter specifications. As a consequence, the illustrations are not
a representation of a complete workpiece and are not of a quality that is required for use in
industry (in terms of full conformity with the standards prepared by ISO/TC 10 and ISO/TC 213),
and as such are not suitable for projection for teaching purposes.
1 Scope
This document gives the rules for geometrical specifications of integral and derived features, using the
line profile and surface profile characteristic symbols as defined in ISO 1101.
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 1101:2017, Geometrical product specifications (GPS) — Geometrical tolerancing — Tolerances of form,
orientation, location and run-out
ISO 5459:2011, Geometrical product specifications (GPS) — Geometrical tolerancing — Datums and
datum systems
ISO 8015:2011, Geometrical product specifications (GPS) — Fundamentals — Concepts, principles and rules
ISO 16792, Technical product documentation — Digital product definition data practices
ISO 17450-1, Geometrical product specifications (GPS) — General concepts — Part 1: Model for geometrical
specification and verification
ISO 17450-3, Geometrical product specifications (GPS) — General concepts — Part 3: Toleranced features
ISO 22432, Geometrical product specifications (GPS) — Features utilized in specification and verification
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 1101, ISO 5459, ISO 8015,
ISO 17450-1, ISO 17450-3, ISO 22432 and the following apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— IEC Electropedia: available at http:// www .electropedia .org/
— ISO Online browsing platform: available at http:// www .iso .org/ obp
3.1
profile tolerancing
geometrical tolerancing using the line profile symbol or the surface profile symbol
ISO 1660:2017(E)
3.2
line profile
property of a line
3.3
surface profile
property of a surface
3.4
non-redundant degree of freedom
degree of freedom for which the tolerance zone is not invariant
4 Symbols
See Table 2.
Table 2 — Symbols for geometrical characteristics
Line profile symbol
Surface profile symbol
These symbols shall be used in the characteristic section of the tolerance indicator, see ISO 1101:2017, 8.2.
The nominal features, for which each symbol can be used, are given in Table 3.
Table 3 — Valid geometrical characteristic symbol and nominal toleranced feature
combinations
Toleranced feature
Integral straight line X
Derived straight line X
Integral non-straight line X
Derived non-straight line X
Integral flat surface X
Derived flat surface X
Integral non-flat surface X
Derived non-flat surface X
For straight lines and planes, there are other characteristic symbols that directly provide the
information about the shape of the toleranced feature, e.g. flatness for planes and straightness for
straight lines. The profile characteristic symbols may be used for straight lines and planes. However, in
this case, to determine the nominal shape of the toleranced feature, it is necessary to verify that there is
no indication that the feature is nominally non-flat or non-straight on the drawing or in the CAD model,
as applicable.
NOTE A nominally planar surface and a nominally curved surface with a large radius may both appear as
a straight line on the drawing and the profile characteristic symbols can be used for both types of surfaces.
However, for the curved surface there will be an indication on the drawing or explicit or implicit TEDs in the
CAD model, that the surface is not flat. For the planar surface, there will be no such indication on a drawing. On a
drawing, it is this indication or absence of indication that is used to determine the nominal shape of the feature in
this case. In a CAD model, the model data are used to determine the nominal shape of the feature.
Additional symbols used in this document are given in Table 4 along with a reference to where they are
defined.
2 © ISO 2017 – All rights reserved

ISO 1660:2017(E)
Table 4 — Additional symbols used in this document
Description Symbol Reference
Combined zone ISO 1101:2017, 8.2.2.1.2
Separate zones ISO 1101:2017, 8.2.2.1.2
Unspecified linear tolerance zone offset ISO 1101:2017, 8.2.2.1.4.1
Specified tolerance zone offset ISO 1101:2017, 8.2.2.1.3
United feature ISO 1101:2017, 3.9
Between ISO 1101:2017, 9.1.4
Unspecified angular tolerance zone offset ISO 1101:2017, 8.2.2.1.4.2
All around ISO 1101:2017, 9.1.2
All over ISO 1101:2017, 9.1.2
Collection plane indicator ISO 1101:2017, 16
Intersection plane indicator ISO 1101:2017, 13
Direction feature indicator ISO 1101:2017, 15
Orientation constraint only ISO 5459:2011, 7.4.2.8
5 Rules for profile tolerancing
5.1 General
For the basic rules for geometrical tolerancing, of which profile tolerancing is a part, see ISO 1101.
When a drawing shall be used in conjunction with a CAD model, an unambiguous reference to the CAD
model shall be made on the drawing and the CAD model shall comply with ISO 16792.
According to the feature principle (see ISO 8015:2011, 5.4), by default a profile specification applies
to one complete single feature as defined in ISO 22432. It is the designer’s responsibility to select the
features or parts of features to which a specification applies and either indicate that on a 2D drawing
using appropriate symbology or define it in the CAD model.
According to the independency principle (see ISO 8015:2011, 5.5), by default a profile specification that
applies to more than one single feature as defined in ISO 22432, applies to those features independently.
If it is desired that the profile specification applies to the features as if they were one, or with some
constraint amongst the tolerance zones for the single features, it is the designer’s responsibility to
either indicate this on a 2D drawing using appropriate symbology or define it in the CAD model.
The “all over” indication and the “all around” indication shall always be combined with UF, CZ or SZ,
when used for geometrical tolerancing, to make it explicit whether the specification applies to a united
feature, defines a combined zone or defines a set of separate zones, except when all the non-redundant
degrees of freedom for all the tolerance zones are locked by reference to datums.
NOTE 1 The meaning of CZ and SZ is identical when the specification defines a set of tolerance zones for which
all non-redundant degrees of freedom are locked by reference to datums.
NOTE 2 In previous revisions of this document, “all around” was used without any other indication. That
made it ambiguous whether the specification applied to the features independently or the specification defined a
combined zone. The requirement to always use UF, CZ or SZ is a failsafe indication.
ISO 1660:2017(E)
5.2 Default rules for profile tolerancing
5.2.1 Rule A: Definition of the theoretically exact feature (TEF)
The theoretically exact feature (TEF) of the toleranced feature shall be defined with theoretically exact
dimensions (TEDs) or be embedded in the CAD model. For a feature of size, the nominal shape of the
TEF shall be defined, but the nominal size of the TEF may be undefined, see Figure 4 b).
These TEDs may include:
— explicit TEDs;
— implicit TEDs;
— tables of values and interpolation algorithms;
— mathematical functions including splines and other formulae;
— reference to CAD model queries.
A TEF that appears to be a nominally straight line or a nominal plane on the drawing with no explicit
indication to the contrary, shall be considered a nominally straight line or a nominal plane, respectively,
defined by implicit TEDs.
The shape of a TEF that is nominally a circle, a cylinder, a sphere or a cone is implicitly defined.
The shape of a TEF that is nominally a torus is defined when the directrix size is defined by an
explicit TED.
The size of a feature of size is undefined, and shall therefore be considered variable, unless it is defined
by an explicit TED, see Figures 1 and 4. The size of the generatrix of a torus is undefined, unless it is
defined by an explicit TED. See also rules F and G.
NOTE The diameter of the median surface of the tolerance zone is fixed at the nominal size.
Figure 1 — Surface profile specification for a sphere of defined nominal size, given by a TED
If the TEF of a feature is defined by a table with sets of coordinates, the interpolation algorithm for
defining points between the given coordinates shall also be defined.
NOTE 1 There is no standardized way to indicate the interpolation algorithm.
NOTE 2 A non-exhaustive list of interpolation algorithms includes:
— linear interpolation;
— cubic spline interpolation (with or without periodicity conditions);
— NURBS.
EXAMPLE The points are connected by straight lines.
4 © ISO 2017 – All rights reserved

ISO 1660:2017(E)
When the TEF is embedded in the CAD model, it shall comply with ISO 16792.
5.2.2 Rule B: Type of toleranced feature
The rules for indicating whether the toleranced feature is an integral feature or a derived feature are
given in ISO 1101:2017, Clause 6.
When the characteristic symbol in the tolerance indicator is the surface profile symbol, the toleranced
feature is an integral or derived surface.
When the characteristic symbol in the tolerance indicator is the line profile symbol, the toleranced
feature is either
— the derived feature (see B.15),
— any line in the identified integral or derived surface, in a specified direction (see B.14), or
— one specified line in the identified integral or derived surface.
If the toleranced feature is one identified line in a surface, the location of this line shall be identified
by TEDs.
If the toleranced feature is any line in the identified surface in a specified direction, then that direction
shall be identified using an intersection plane indicator, see ISO 1101:2017, Clause 13.
5.2.3 Rule C: Definition of the tolerance zone
See Figure 2.
For surface profile characteristics, the tolerance zone is limited by two surfaces enveloping spheres
with a diameter equal to the tolerance value, the centres of which are situated on the TEF (see Figure 2),
unless otherwise specified, see rules E, F and H.
For line profile characteristics, when the tolerance is constant and not preceded by ⌀, the tolerance
zone is limited by two lines enveloping circles with a diameter equal to the tolerance value, the centres
of which are situated on the TEF, unless otherwise specified, see rules E, F and H.
For line profile characteristics, when the toleranced feature is a derived line and the tolerance value is
preceded by ⌀, the tolerance zone is limited by a tube enveloping spheres with a diameter equal to the
tolerance value, the centres of which are situated on the TEF, unless otherwise specified, see rule H.
NOTE See also ISO 1101:2017, 8.2.2.1.1.
ISO 1660:2017(E)
Key
1 TEF
2 two of the infinite number of spheres or circles defining the tolerance zone along the TEF
3 tolerance zone limits
t tolerance value
Figure 2 — Definition of tolerance zone
For line profile characteristics for integral features, the orientation of the intersection plane that
contains the tolerance zone may be completely defined by the intersection plane indicator, e.g. when it
is specified to be parallel to a datum plane or perpendicular to a datum axis.
In other cases, e.g. when it is specified to be perpendicular to a datum plane or parallel to a datum axis,
one orientation angle remains unlocked. In this case, the intersection plane shall be perpendicular to
the surface, see Figure 3, if being perpendicular to the surface defines a consistent direction for each
line profile.
If being perpendicular to the surface does not define a consistent direction along each line profile, e.g.
for complex surfaces that are twisted along the line profile, and the intersection plane has an unlocked
orientation angle, a direction feature indicator shall be used to define the second orientation angle of
the intersection plane.
6 © ISO 2017 – All rights reserved

ISO 1660:2017(E)
a) Specification b) Orientation of the intersection plane
containing the tolerance zone
Key
1 the intersection plane is perpendicular to datum plane B
2 the intersection plane is locally perpendicular to the toleranced feature
Figure 3 — Orientation of the intersection plane that contains the tolerance zone for line profile
characteristics
5.3 Rules for profile tolerancing using additional specification elements
5.3.1 Rule D: Toleranced feature specification elements
If the toleranced feature is not one complete single feature, this shall be indicated by using the tools
given in ISO 1101, e.g. the SZ, CZ, UF, “all over”, “all around” and “between” specification elements,
or by query of the CAD model (see B.5, NOTE 2). To avoid ambiguities, the “all over” and “all around”
specification elements shall always be used together with either the SZ, CZ or UF specification element
for geometrical specifications, unless all the non-redundant degrees of freedom of the tolerance zones
are locked by a datum system.
The SZ, separate zones, modifier considers the set of single features as separate features, with unrelated
tolerance zones. Since there are a number of toleranced features, there are an equal number of specified
characteristics.
The CZ, combined zone, modifier considers the set of single features as separate features, but combines
the tolerance zones. Since it builds a collection of toleranced features, it cannot define a derived feature,
if the individual features do not have a derived feature. Therefore, the CZ modifier is appropriate to use
when the toleranced features function separately, but with a relation between them. The CZ modifier
defines only one specified characteristic.
The UF, united feature, modifier builds one compound feature out of several single features. This
compound feature may have a derived feature, even when the individual features do not. Therefore,
the UF modifier is appropriate to use when the function(s) is related to the integral compound feature
considered as one feature, or to its derived feature.
A specification for a united feature or its derived feature creates one tolerance zone for that compound
feature or derived feature. Since there is only one compound feature, there is only one specified
characteristic.
In the case of profile tolerancing of integral features, the practical difference between UF and CZ is
small and limited to the shape of the tolerance zone in transitions between features.
ISO 1660:2017(E)
5.3.2 Rule E: Unequally disposed tolerance zone
If, for integral features, the tolerance zone is not equally disposed according to rule C, the UZ
specification element shall be used. The rules are given in ISO 1101:2017, 8.2.2.1.3.
5.3.3 Rule F: Linear tolerance zone offset
If the tolerance zone is allowed to be offset from the TEF by a consistent, but unspecified amount, the OZ
specification element shall be indicated in the tolerance indicator. The rules are given in ISO 1101:2017,
8.2.2.1.4.1.
In the case of a feature of linear size, when a tolerance zone shall not take the nominal size into account,
the OZ modifier shall be indicated, see Figure 4 a). If the shape of the TEF is defined, but the nominal
linear size of the TEF is undefined, the OZ modifier shall always be indicated, see Figure 4 b).
a) Surface profile specification for a sphere of b) Surface profile specification for a sphere of
defined nominal size, given by a TED with OZ undefined nominal size with OZ indication
indication
NOTE The diameter of the median surface of the tolerance zone is variable.
Figure 4 — Surface profile specifications features of linear size with OZ modifier
NOTE Because there are no bounds on the offset, a specification with the OZ modifier, such as the one in
Figure 4 a) and b), is usually combined with a specification using a larger tolerance without the OZ modifier, such
as the one in Figure 1. When both tolerances are satisfied, this combination controls the shape of the tolerance
feature within the larger, fixed tolerance zone.
5.3.4 Rule G: Angular tolerance zone offset
In the case of a feature of angular size, when a tolerance zone shall not take the nominal size into
account, the VA modifier (variable angular size) shall be indicated. If the shape of the TEF is defined, but
the nominal angular size of the TEF is undefined, the VA modifier shall always be indicated. The rules
are given in ISO 1101:2017, 8.2.2.1.4.2.
5.3.5 Rule H: Variable tolerance zone width
If the tolerance zone width is variable, this shall be indicated using the tools given in ISO 1101:2017,
8.2.2.1.1.
5.3.6 Rule I: Filtered feature specification elements
If the specification applies to an extracted feature with a specified filtering applied, this shall be
indicated using the tools given in ISO 1101:2017, 8.2.2.2.1.
8 © ISO 2017 – All rights reserved

ISO 1660:2017(E)
5.3.7 Rule J: Association and parameter specification elements
If an unrelated profile characteristic (profile form specification) applies relative to a non-default
reference feature, to a non-default parameter, or both, this shall be indicated using the tools given in
ISO 1101:2017, 8.2.2.3.1 and 8.2.2.3.2.
NOTE The default association criterion and parameter are given in ISO 1101:2017, 8.2.2.3.1 and 8.2.2.3.2.
5.3.8 Rule K: Associated toleranced feature specification elements
If the specification applies to an associated feature and not the identified feature itself, this shall be
indicated using the tools given in ISO 1101:2017, 8.2.2.2.2.
5.3.9 Rule L: Non-rigid part
If the specification applies to a non-rigid part in a restrained or non-restrained condition, the indications
and rules given in ISO 10579 apply.
ISO 1660:2017(E)
Annex A
(informative)
Compound features
Compound features not fully defined by TEDs and features that are of one of the types as given in rule
A, but do not meet the requirements of the rule with regards to dimensions defined by TEDs have no
unambiguous defined form and therefore cannot be specified by profile characteristics. Figure A.1
shows some examples.
a) b)
c) d) e)
Figure A.1 — Features with ambiguous geometry
The TEF of the feature in Figure A.1 a) is ambiguous because the nominal distance between the two
half-circles is not defined.
The TEF of the feature Figure A.1 b) is ambiguous because the nominal radius of one of the two half-
circles is not defined.
The TEF of the feature in Figure A.1 c) is ambiguous because the nominal distance between the arc
centres is not defined.
The TEF of the feature in Figure A.1 d) is ambiguous because the nominal diameter of the arcs is not
defined.
The TEF of the feature in Figure A.1 e) is ambiguous because the nominal size of the directrix is not
defined.
10 © ISO 2017 – All rights reserved

ISO 1660:2017(E)
a)
b)
c)
Figure A.2 — Features with unambiguous geometry
NOTE 1 CZ could have been used instead of UF in Figure A.2 a) and Figure A.2 b).
NOTE 2 The distance between the planes in Figure A.2 b) is implicitly given as 10, because they are shown
tangential to the half cylinders.
The TEF of the feature in Figure A.2 a) is unambiguous because the nominal radii of the half-circles as
well as the distance between the two circles are defined by explicit and implicit TEDs.
The TEF of the feature in Figure A.2 b) is unambiguous because both the nominal diameter of the arcs
and the nominal distance between the arc centres are defined by explicit and implicit TEDs.
The TEF of the feature in Figure A.2 c) is unambiguous because the nominal size of the directrix is
defined by a TED.
ISO 1660:2017(E)
Annex B
(informative)
Illustration of the rules
B.1 General
The following examples are intended to illustrate the fundamental rules as well as rules A to F. They do
not add to the rules, subtract from the rules or change the rules.
— Example 1: Surface profile specification for a single feature (B.2).
— Example 2: Surface profile specification for compound feature (B.3).
— Example 3: Surface profile specification for a set of independent features (B.4).
— Example 4: Surface profile specification for a united feature (B.5).
— Example 5: Unequally disposed surface profile specification for a united feature (B.6).
— Example 6: Offset surface profile specification for a united feature (B.7).
— Example 7: Combined surface profile specification for a set of features (B.8).
— Example 8: Surface profile specification for compound feature completely constrained by
datums (B.9).
— Example 9: Combination of a fixed and an off-set specification (B.10).
— Example 10: Unequally disposed surface profile specification constrained by datums (B.11).
— Example 11: Surface profile specification for compound feature partially constrained by datums
(B.12).
— Example 12: Surface profile specification for two independent features partially constrained by
datums (B.13).
— Example 13: Line profile specification for a single feature (B.14).
— Example 14: Line profile specification for a compound derived feature (B.15).
— Example 15: Surface profile specification for a compound derived feature (B.16).
— Example 16: Surface profile specification for a complex compound feature (B.17).
NOTE Not all TEDs are necessary for the interpretation of the specification indicated in each example.
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ISO 1660:2017(E)
B.2 Example 1: Surface profile specification for a single feature
a) 2D drawing indication b) 3D drawing indication
c) Tolerance zone
Figure B.1 — Surface profile specification for a single feature
The drawing indications in Figure B.1 a) and b) shall be interpreted as follows:
— According to the feature principle, the specification applies to one complete feature, i.e. the feature
identified by the leader line, which is a feature that forms a 90° section of a cylinder with a nominal
radius of 20.
— According to rule A, the TEF shall be defined with theoretically exact dimensions. In this case, the
toleranced feature is defined as part of a cylinder with a radius of 20.
— According to rule B, the toleranced feature is a surface and according to the indication rules given
in ISO 1101:2017, Clause 6, the toleranced feature is an integral surface.
— According to rule C, the tolerance zone is limited by two equidistant su
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