SIST EN ISO 5456-4:2002

• Status: Published
• Publication Date: 31-Jan-2002
• ICS: 01.100.01 - Technical drawings in general
• Technical Committee: TRS - Technical drawings, quantities, units, symbols and graphical symbols
• Current Stage: 6060 - National Implementation/Publication (Adopted Project)
• Start Date: 01-Feb-2002
• Due Date: 01-Feb-2002
• Completion Date: 01-Feb-2002
• Ref Project: EN ISO 5456-4:2001 - Technical drawings - Projection methods - Part 4: Central projection (ISO 5456-4:1996)

SIST EN ISO 5456-4:2002 is the Slovenian standard published by SIST for technical drawings. It adopts EN ISO 5456-4:2001, which presents ISO 5456-4:1996 without modification, and it specifies how to use central projection in technical drawings. The document is aimed at people who prepare, check, teach, or interpret perspective representations, especially in technical drafting and architectural drawing.

What does SIST EN ISO 5456-4:2002 specify?

SIST EN ISO 5456-4:2002 specifies the basic rules for the development and application of central projection in technical drawings. Its focus is one projection method in the ISO 5456 series, while the other parts cover orthographic and axonometric representations.

The document is organized into:

• Clause 1 - Scope
• Clause 2 - Normative reference
• Clause 3 - Definitions
• Clause 4 - Symbols
• Clause 5 - Central projection methods
• Clause 6 - Principle
• Clause 7 - Principles and methods of depiction
• Clause 8 - Development of a central projection
• Annex A - Informative examples for comparison of different depiction methods
• Annex B - Informative bibliography
• Annex ZA - Normative references to international publications with their European publications

Annex	What it covers
A	Comparison examples for the depiction methods described in clause 7
B	Bibliography of related standards and references
ZA	Normative reference mapping for the European standard

What are the key requirements of SIST EN ISO 5456-4:2002?

SIST EN ISO 5456-4:2002 is built around the geometry of central projection and the practical methods used to construct it. The important point for users is that the chosen method depends on where the object sits relative to the projection plane and on how much distortion or construction work is acceptable.

Choosing the projection method

Clause 5 defines four basic ways to handle central projection. The one-point method suits objects with a principal face parallel to the projection plane; parallel outlines on that face keep their direction, which makes front-facing views easy to read.

The two-point method suits objects whose vertical outlines and edges are parallel to the projection plane. Horizontal lines then meet at vanishing points on the horizon line, which is why this method is common for corner views.

The three-point method covers objects in any position. It is used when no outlines or edges are parallel to the projection plane, and it also handles inclined projection planes.

Clause 5.4 describes the coordinate method, which uses simple proportions and calculated image coordinates. In practice, this is useful when a drawing is prepared from measured point coordinates rather than by direct geometric construction.

Controlling image size and distortion

Clause 6.1 explains that image size changes when the projection plane is moved. If the object is in front of the projection plane, the representation becomes larger; if it is behind the plane, the image becomes smaller. That matters when a draughtsperson needs a view that fills the sheet or a smaller view that fits a layout.

Clause 6.2 sets the visual conditions for a clear image. To avoid strong peripheral distortion, the object should be placed within a vision cone with an aperture angle not greater than 60°, and the rays should stay close to the main projector. In practice, this keeps the perspective readable and prevents the edges of the image from looking unnaturally stretched.

Clause 6.3 links distance to appearance. Increasing the distance between the projection centre and the projection plane enlarges and flattens the image in some arrangements, so the chosen distance directly affects how natural the perspective looks.

Constructing the drawing

Clause 7.1 describes the piercing method, where piercing points are found by drawing or calculation. It is presented as a way to handle even complex shapes, including round forms and helicoids, without changing the projection principles.

Clauses 7.2 to 7.5 present several construction methods:

• trace point - vanishing point methods for special and particular object positions
• distance point method for setting up a perspective grid
• scale point method for transferring dimensions on depth lines
• trace point method with an inclined projection plane

These methods matter because they give the draughtsperson different ways to control vanishing points, depth, and dimension transfer depending on the object and the intended visual result.

Clause 7.6 gives the coordinate piercing method. It works from reference planes and a Cartesian coordinate system in the projection plane, then transfers calculated image coordinates to scale. This is the method to use when the perspective view must be derived from coordinates rather than from a purely geometric drawing procedure.

Developing the final view on the drawing surface

Clause 8 explains how the basic plane can be turned into the projection plane to create the final representation. It describes two layout choices: a regular arrangement and an economy arrangement. The practical difference is sheet space - one gives the best overview, while the other saves space on the drawing surface.

What terms does SIST EN ISO 5456-4:2002 define?

SIST EN ISO 5456-4:2002 defines several projection terms that are used throughout the methods and figures.

• alignment line - A line parallel to a given line and passing through the projection centre; where it meets the projection plane, it gives the vanishing point of all lines parallel to that line.
• height of projection - The vertical distance from the projection centre to the basic plane.
• horizontal distance - The distance between the projection centre and the projection plane.
• projection angle - The angle formed by the projection plane and the horizon plane.
• scale point - The vanishing point used to recover true length on certain horizontal directions in the drawing.
• station of observation (Sp) - The orthogonal projection of the projection centre onto the basic plane.

Who uses SIST EN ISO 5456-4:2002?

SIST EN ISO 5456-4:2002 is used by technical illustrators, draughtspersons, engineers, architects, and documentation specialists who need to create or review perspective representations. It is also relevant in technical product documentation, where a consistent method for central projection helps teams produce drawings that are easier to interpret and compare.

In practice, it supports:

• architectural drawings and space views
• product definition and related documentation
• technical drawing training and checking
• preparation of perspective views from measured geometry or coordinates

What changed in SIST EN ISO 5456-4:2002 from the previous edition?

SIST EN ISO 5456-4:2002 is the Slovenian adoption of EN ISO 5456-4:2001, and the European standard states that ISO 5456-4:1996 was approved without modification. The ISO publication is identified as the first edition, corrected and reprinted in 1998.

Which standards are used with SIST EN ISO 5456-4:2002?

Standard	What it contributes
ISO 10209-2	Vocabulary for terms relating to projection methods; used as the normative reference in Annex ZA
ISO 5456-1	Synopsis of the ISO 5456 projection methods series
ISO 5456-2	Orthographic representations
ISO 5456-3	Axonometric representations

What does the SIST EN ISO 5456-4:2002 document contain?

SIST EN ISO 5456-4:2002 contains the projection model figures, the vision cone and vision angle figures, and construction figures for one-point, two-point, three-point, distance point, scale point, and coordinate methods. It also includes Table 1 of letter symbols used in central projection.

Annex A adds 17 informative comparison examples, including exterior and interior views, section perspectives, wire-frame models, surroundings, and inclined projection plane cases. Clause 7.6 includes a calculation-based coordinate method, and clause 8 shows how the perspective view is laid out on the drawing surface. Annex B gives the bibliography, and Annex ZA gives the European mapping of normative references.

SLOVENSKI STANDARD
01-februar-2002
7HKQLþQHULVEH0HWRGHSURMHNFLMHGHO&HQWUDOQDSURMHNFLMD,62
Technical drawings - Projection methods - Part 4: Central projection (ISO 5456-4:1996)
Technische Zeichnungen - Projektionsmethoden - Teil 4: Zentralprojektion (ISO 5456-
4:1998)
Dessins techniques - Méthodes de projection - Partie 4: Projection centrale (ISO 5456-
4:1996)
Ta slovenski standard je istoveten z: EN ISO 5456-4:2001
ICS:
01.100.01 7HKQLþQRULVDQMHQDVSORãQR Technical drawings in
general
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD
EN ISO 5456-4
NORME EUROPÉENNE
EUROPÄISCHE NORM
October 2001
ICS 01.100.10
English version
Technical drawings - Projection methods - Part 4: Central
projection (ISO 5456-4:1996)
Dessins techniques - Méthodes de projection - Partie 4: Technische Zeichnungen - Projektionsmethoden - Teil 4:
Projection centrale (ISO 5456-4:1996) Zentralprojektion (ISO 5456-4:1998)
This European Standard was approved by CEN on 30 September 2001.
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 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 Management Centre has the same status as the official
versions.
CEN members are the national standards bodies of Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece,
Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: rue de Stassart, 36  B-1050 Brussels
© 2001 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 5456-4:2001 E
worldwide for CEN national Members.

CORRECTED 2002-01-02
Foreword
The text of the International Standard from Technical Committee ISO/TC 10 "Technical drawings,
product definition and related documentation" of the International Organization for Standardization
(ISO), the secretariat of which is held by CMC.
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 April 2002, and conflicting national standards shall be
withdrawn at the latest by April 2002.
According to the CEN/CENELEC Internal Regulations, the national standards organizations of the
following countries are bound to implement this European Standard: Austria, Belgium, Czech Republic,
Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands,
Norway, Portugal, Spain, Sweden, Switzerland and the United Kingdom.
Endorsement notice
The text of the International Standard ISO 5456-4:1996 has been approved by CEN as a European
Standard without any modification.
NOTE Normative references to International Standards are listed in annex ZA (normative).
Annex ZA
(normative)
Normative references to international publications
with their relevant European publications
This European Standard incorporates by dated or undated reference, provisions from other publications.
These normative references are cited at the appropriate places in the text and the publications are listed
hereafter. For dated references, subsequent amendments to or revisions of -any of these publications
apply to this European Standard only when incorporated in it by amendment or revision. For undated
references the latest edition of the publication referred to applies (including amendments).
NOTE Where an International Publication has been modified by common modifications, indicated by
(mod.), the relevant EN/HD applies.
Publication Year Title EN Year
ISO 10209-2 1994 Technical product documentation - EN ISO 10209-2 1996
Vocabulary - Part 2: Terms relating to
projection methods
INTERNATIONAL ISO
STANDARD 5456-4
First edition
1996-06-15
Corrected and reprinted
1998-08-01
Technical drawings — Projection
methods —
Part 4:
Central projection
Dessins techniques — Méthodes de projection —
Partie 4: Projection centrale
A
Reference number
ISO 5456-4:1996(E)
ISO 5456-4:1996(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 rep-
resented 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.
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.
International Standard ISO 5456-4 was prepared by Technical Committee
ISO/TC 10, Technical drawings, product definition and related documen-
tation, Subcommittee SC 1, Basic conventions.
ISO 5456 consists of the following parts, under the general title Technical
drawings — Projection methods:
— Part 1: Synopsis
— Part 2: Orthographic representations
— Part 3: Axonometric representations
— Part 4: Central projection
Annexes A and B of this part of ISO 5456 are for information only.
©  ISO 1996
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 the publisher.
International Organization for Standardization
Case postale 56 • CH-1211 Genève 20 • Switzerland
Internet [e-mail]
Printed in Switzerland
ii
©
ISO ISO 5456-4:1996(E)
Introduction
Central projection (perspective) is a realistic pictorial representation ob-
tained by projecting the object to be represented from a point at finite
distance (projection centre) on a single projection plane (normally the
drawing surface). Central projection provides excellent visual appearance
of the object (monocular vision) and is often used in architectural draw-
ings.
iii
©
INTERNATIONAL STANDARD  ISO ISO 5456-4:1996(E)
Technical drawings — Projection methods —
Part 4:
Central projection
3.1  alignment line: Line parallel to a given line
1  Scope
passing through the projection centre. Its intersection
with the projection plane gives the vanishing point of
This part of ISO 5456 specifies basic rules for the
all lines parallel to the given line.
development and application of central projection in
technical drawings.
3.2  height of projection: Vertical distance of the
2  Normative reference
projection centre from the basic plane.
The following standard contains provisions which,
through reference in this text, constitute provisions of
3.3  horizontal distance: Distance between the
this part of ISO 5456. At the time of publication, the
projection centre and the projection plane.
edition indicated was valid. All standards are subject
to revision, and parties to agreements based on this
part of ISO 5456 are encouraged to investigate the
possibility of applying the most recent edition of the
3.4  projection angle: Angle formed by the projec-
standard indicated below. Members of IEC and ISO
tion plane and the horizon plane.
maintain registers of currently valid International
Standards.
3.5  scale point: Vanishing point of the horizontal
ISO 10209-2:1993, Technical product documentation
— Vocabulary — Part 2: Terms relating to projection direction orthogonal to that bisecting the angle formed
by the horizon line and the alignment line of the given
methods.
horizontal line, and allowing the true length of the
projection of the given line to be determined.
3  Definitions
For the purposes of this part of ISO 5456, the defi-
nitions given in ISO 10209-2 and the following defi- 3.6  station of observation: Orthogonal projection
of the projection centre onto the basic plane.
nitions apply.
©
ISO 5456-4:1996(E) ISO
tation (horizontal lines remain horizontal and vertical
4  Symbols
lines remain vertical). All lines perpendicular to the
projection plane converge at the vanishing point, V,
Letter symbols for terms used in central projection
coinciding with the main point, C, (see figure 3 and
are given in table 1 and illustrated in figures 1 and 2,
7.2.1 and 7.3).
as well as in the figures mentioned in table 1.
5.2  Two-point method
Table 1 — Letter symbols
A two-point projection method is a central projection
No. Term Letter symbol Figure
of an object having its vertical outlines and edges
1)
Projection plane T 1 parallel to the projection plane (particular position). All
horizontal lines of a representation converge at multi-
1)
Basic plane G 1
ple vanishing points V , V , V , ., on the horizon line
1 2 3
1)
Basic line X 1 (see figure 4 and 7.2.2 and 7.4).
3.4 Projection angle b 5
1) 5.3  Three-point method
Horizon plane HT 1
1)
Horizon line h 1
A three-point projection method is a central projection
3.1 Alignment line Vl 4 of an object having no outlines or edges parallel to the
projection plane (any position). If the projection plane
1)
Main point C 1
is inclined towards the projection centre, i.e. b > 90°,
1)
Vanishing point V 4
the vanishing point for vertical lines is situated below
the horizon line (see figure 5 and 7.5.1 and 7.5.2).
1)
Main projector pL 1
1)
Projection centre O 1
5.4  Coordinate method
3.2 Height of projection H 1
3.3 Horizontal distance d 1
Representation by the coordinate method is based on
simple proportions.
1)
Vision cone K 2
1)
Circle of vision Ks 3
The coordinates, related to the main projector of all
1)
relevant points of the object to be represented, are
Vision angle a 2
taken by the graphic method from the basic plane and
1)
Projector Pl 3
elevation. From these point coordinates, the image
1)
Distance point DP 13
coordinates are obtained by a calculation method and
entered to scale. The image points are connected to
3.5 Scale point MP 14
each other to provide a clear representation of the
3.6 Station of observation Sp 1
object (see figure 6).
1)  Terms already defined in ISO 10209-2.
6  Principle
5  Central projection methods
6.1  Location and position of the projection
plane
The mode of the central projection depends on the
position of the object to be represented with respect
The image size of an object can be varied by parallel
to the projection plane.
shifting of the projection plane. If the object is placed
in front of the projection plane, the representation will
For possible positions and applicable projection
be enlarged. The object behind the projection plane
methods, see 5.1 to 5.4.
will result in a smaller image. Figure 7 shows the
change in image size depending on the position of the
5.1  One-point method
object with respect to the projection plane.
A one-point projection method is a central projection
Figure 8 shows the change in image size depending
of an object having its principal face parallel to the
on the method of representation with vertical or
projection plane (special position). All parallel outlines
inclined projection planes. b is the included angle
and edges of the object which are parallel to the
between the projection plane and the basic plane near
projection plane retain their direction in this represen- the projection centre.
©
ISO ISO 5456-4:1996(E)
Figure 1 — Projection model of the central projection
©
ISO 5456-4:1996(E) ISO
Figure 2 — Vision cone and vision angle in the projection model of the central projection
©
ISO ISO 5456-4:1996(E)
Figure 3 — Projection model with vertical projection plane and an object in a special position
with respect to the projection plane
Figure 4 — Projection model with vertical projection plane and an object in a particular position
with respect to the projection plane
©
ISO 5456-4:1996(E) ISO
Figure 5 — Projection model with inclined projection plane and an object in any position with respect
to the projection plane (b > 90°)
©
ISO ISO 5456-4:1996(E)
Figure 6 — Projection model with vertical projection plane and an object in special position, showing the
lengths used in the mathematical formula for calculation of the perspective image
b = 90°, b > 90°; b < 90°
1 2
Figure 7 — Location of projection planes Figure 8 — Position of projection planes
©
ISO 5456-4:
...