EN 9300-120:2023

Aerospace series - LOTAR - LOng Term Archiving and Retrieval of digital technical product documentation such as 3D CAD and PDM data - Part 120: CAD 3D explicit geometry with graphic product and manufacturing information

1.1 Introduction
This document defines the requirements for the long term digital preservation of the presentation of Product and Manufacturing Information (PMI) with their possible links to the 3D explicit shape and geometry of single CAD parts. The goal is to preserve this 3D information with respect to the geometry and related PMI produced by the original CAD system, following the principles laid down in EN 9300 003 “Fundamentals and Concepts”.
The requirements of EN 9300 110 “CAD mechanical 3D explicit geometry information” about the preservation of the 3D explicit shape shall apply within this document.
The meaning of terms "Presentation" and "Representation", defined in the EN 9300 100 “Common concepts for Long term archiving and retrieval of CAD 3D mechanical information” is required to understand this EN 9300 document.
1.2 In scope
The following outlines the total scope of this document:
- the Presentation of 3D geometrical dimension and tolerance, and 3D annotation attributes;
- their possible semantic links with 3D Geometric shape;
- User Defined Attributes: that are assigned to 3D geometric entities or at the part level.
For the purpose of this document, the semantic definition is at the level that supports associative “Cross-highlighting”, to illustrate the portion of the geometry to which a PMI element applies.
In this version, the technology used to preserve this 3D information is based on polyline and tessellated presentation. Polyline presentation is a conversion to lines and curves of all 3D annotations by the STEP interfaces of the CAD system, including validation properties.  Tessellated presentation is a conversion to tessellated curves and tessellated faces. The main use cases are the Certification and Product Liability of static information, however, re-use is also possible after the deletion of previous PMI and creation of new PMI (refer to clause 3 for definition).
1.3 Out of scope
The following is outside the scope:
- machine-interpretable PMI “Representation”;
- how to preserve additional information:
- - property rights;
- -form features;
- -machining features;
- CAD Assemblies.

Luft- und Raumfahrt - LOTAR - Langzeit-Archivierung und -Bereitstellung digitaler technischer Produktdokumentationen, wie zum Beispiel von 3D-, CAD- und PDM-Daten - Teil 120: Eindeutige 3D-CAD-Geometrie mit grafischen Produkt- und Fertigungsinformationen

Série aérospatiale - LOTAR - Archivage long terme et récupération des données techniques produits numériques, telles que CAD 3D et PDM - Partie 120: CAO 3D explicite et informations graphiques 3D pour la fabrication du produit

Aeronavtika - LOTAR - Dolgotrajno arhiviranje in iskanje digitalne tehnične dokumentacije o izdelkih, kot so podatki o 3D, CAD in PDM - 120. del: CAD 3D eksplicitne informacije o geometriji z grafičnim izdelkom in izdelavo

1.1 Uvod
Ta dokument določa zahteve za dolgoročno digitalno shranjevanje predstavitve informacij o grafičnem izdelku in proizvodnji (PMI) z morebitnimi povezavami do 3D eksplicitne oblike in geometrije posameznih delov CAD. Cilj je ohraniti 3D informacije glede na geometrijo ter povezane informacije o grafičnem izdelku in proizvodnji, ki jih proizvede prvotni sistem CAD, v skladu z načeli, določenimi v standardu EN 9300-003 »Osnove in pojmi«.
V tem dokumentu je treba upoštevati zahteve standarda EN 9300-110 »CAD mehanske 3D eksplicitne informacije o geometriji« v zvezi s shranjevanjem 3D eksplicitne oblike.
Za razumevanje tega dokumenta EN 9300 je potreben pomen izrazov »predstavitev« in »prikaz«, opredeljenih v standardu EN 9300-100 »Splošni pojmi za dolgoročno arhiviranje in pridobivanje CAD 3D mehanskih informacij«.
1.2 Znotraj področja uporabe
Naslednje opisuje celotno področje uporabe tega dokumenta:
– predstavitev 3D geometrijskih dimenzij in toleranc ter 3D atributov opomb;
– njihove morebitne semantične povezave s 3D geometrijsko obliko;
– uporabniško določeni atributi, ki so dodeljeni 3D geometrijskim entitetam ali na ravni dela.
Za namene tega dokumenta je semantična definicija na ravni, ki podpira asociativno »navzkrižno poudarjanje« za ponazoritev dela geometrije, za katerega se uporablja element informacij o grafičnem izdelku in proizvodnji.
V tej različici tehnologija, ki se uporablja za shranjevanje 3D informacij, temelji na lomljeni in mozaični predstavitvi. Lomljena predstavitev je pretvorba v črte in krivulje vseh 3D opomb prek vmesnikov STEP sistema CAD, vključno s potrjevalnimi lastnostmi.  Mozaična predstavitev je pretvorba v mozaične krivulje in mozaične ploščice. Glavna primera uporabe sta certificiranje in odgovornost za izdelek v okviru statičnih informacij, vendar je možna tudi vnovična uporaba po izbrisu prejšnjih oziroma ustvarjanju novih informacij o grafičnem izdelku in proizvodnji (za definicijo glej točko 3).
1.3 Zunaj področja uporabe
Naslednje ne spada na področje uporabe:
– »prikaz« strojno berljivih informacij o grafičnem izdelku in proizvodnji;
– način shranjevanja dodatnih informacij;
– lastninske pravice;
– oblikovne lastnosti;
– lastnosti strojne obdelave;
– sestavi CAD.

General Information

• Status: Published
• Publication Date: 31-Oct-2023
• Withdrawal Date: 23-Aug-2020
• ICS: 01.110 - Technical product documentation
• ICS: 35.240.30 - IT applications in information, documentation and publishing
• ICS: 49.020 - Aircraft and space vehicles in general
• Technical Committee: ASD-STAN - Aerospace
• Drafting Committee: ASD-STAN/D 7/WG 1 - LOTAR Long Term Archiving and Retrieval of Digital Technical Product Data
• Current Stage: 6060 - Definitive text made available (DAV) - Publishing
• Start Date: 01-Nov-2023
• Completion Date: 01-Nov-2023
• Ref Project: SIST EN 9300-120:2024 - Aerospace series - LOTAR - LOng Term Archiving and Retrieval of digital technical product documentation such as 3D CAD and PDM data - Part 120: CAD 3D explicit geometry with graphic product and manufacturing information

Overview

EN 9300-120:2023 is a CEN aerospace LOTAR standard that specifies requirements for the long‑term digital preservation of 3D CAD explicit geometry together with the graphic Product and Manufacturing Information (PMI). Focused on single-part CAD data, the standard preserves the presentation of PMI and its semantic links to 3D shape so archived files retain the original CAD system’s visual and contextual intent. The preservation approach in this version relies on polyline and tessellated presentation exported via STEP interfaces.

Key topics and requirements

• Preservation scope
  • Presentation of 3D dimensional and tolerance data, annotations and PMI attributes.
  • Semantic links enabling associative “cross‑highlighting” between PMI elements and the geometry.
  • User Defined Attributes (UDAs) attached to geometry or part level.
• Technology and formats
  • Polyline presentation: conversion of 3D annotations to lines/curves via STEP interfaces (including validation properties).
  • Tessellated presentation: conversion to tessellated curves and faces for reliable visual reproduction.
• Verification and validation
  • Rules and levels for verifying PMI content at ingest and retrieval.
  • Validation properties (e.g., Unicode string validation for PMI text) and reporting to support integrity checks.
• In / Out of scope
  • IN SCOPE: single-part PMI presentation, semantic linking, UDAs, static certification/product‑liability use cases and re‑use after PMI replacement.
  • OUT OF SCOPE: machine‑interpretable PMI representations, CAD assemblies, property rights, form/machining features preservation.

Applications and users

• Primary use cases
  • Certification and product liability evidence where a faithful, long‑term visual record of PMI and 3D shape is required.
  • Archival retrieval for maintenance, regulatory audits, and historical traceability.
  • Re‑use scenarios after original PMI is removed and new PMI is applied.
• Who uses this standard
  • Aerospace OEMs, suppliers and MRO organizations managing LOTAR processes.
  • PLM and CAD administrators and integrators implementing archival workflows.
  • Digital archivists, certification bodies and legal/compliance teams needing defensible long‑term records.
  • CAD/STEP tool vendors ensuring STEP export supports polyline/tessellated PMI presentation and validation metadata.

Related standards

• EN 9300 series (EN 9300-003 Fundamentals and Concepts; EN 9300-100 Common Concepts; EN 9300-110 CAD 3D explicit geometry)
• ISO 10303 (AP203 / AP214 / AP242 / AP514 / AP519)
• ISO 1101, ISO 16792, ASME Y14.41
• CAx‑IF recommended practices for PMI and STEP User Defined Attributes

Keywords: EN 9300-120:2023, LOTAR, long term archiving, PMI, CAD 3D, polyline presentation, tessellated presentation, STEP, validation, aerospace archival.

Standards Content (Sample)

SLOVENSKI STANDARD
01-januar-2024
Aeronavtika - LOTAR - Dolgotrajno arhiviranje in iskanje digitalne tehnične
dokumentacije o izdelkih, kot so podatki o 3D, CAD in PDM - 120. del: CAD 3D
eksplicitne informacije o geometriji z grafičnim izdelkom in izdelavo
Aerospace series - LOTAR - LOng Term Archiving and Retrieval of digital technical
product documentation such as 3D CAD and PDM data - Part 120: CAD 3D explicit
geometry with graphic product and manufacturing information
Luft- und Raumfahrt - LOTAR - Langzeit-Archivierung und -Bereitstellung digitaler
technischer Produktdokumentationen, wie zum Beispiel von 3D-, CAD- und PDM-Daten -
Teil 120: Eindeutige 3D-CAD-Geometrie mit grafischen Produkt- und
Fertigungsinformationen
Série aérospatiale - LOTAR - Archivage long terme et récupération des données
techniques produits numériques, telles que CAO 3D et PDM - Partie 120 : Géométrie
CAO 3D explicite avec données graphiques de produit et de fabrication
Ta slovenski standard je istoveten z: EN 9300-120:2023
ICS:
01.110 Tehnična dokumentacija za Technical product
izdelke documentation
35.240.30 Uporabniške rešitve IT v IT applications in information,
informatiki, dokumentiranju in documentation and
založništvu publishing
49.020 Letala in vesoljska vozila na Aircraft and space vehicles in
splošno general
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EN 9300-120
EUROPEAN STANDARD
NORME EUROPÉENNE
November 2023
EUROPÄISCHE NORM
ICS 01.110
English Version
Aerospace series - LOTAR - LOng Term Archiving and
Retrieval of digital technical product documentation such
as 3D CAD and PDM data - Part 120: CAD 3D explicit
geometry with graphic product and manufacturing
information
Série aérospatiale - LOTAR - Archivage long terme et Série aérospatiale - LOTAR - Archivage long terme et
récupération des données techniques produits récupération des données techniques produits
numériques, telles que CAD 3D et PDM - Partie 120: numériques telles que CAO, 3D et PDM - Partie 120 :
CAO 3D explicite et informations graphiques 3D pour Géométrie CAO 3D explicite avec données graphiques
la fabrication du produit de produit et de fabrication
This European Standard was approved by CEN on 22 December 2019.

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, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and
United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2023 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 9300-120:2023 E
worldwide for CEN national Members.

Contents Page
European foreword . 4
Introduction . 5
1 Scope . 6
1.1 In scope . 6
1.2 Out of scope . 6
2 Normative references . 6
3 Terms, definitions and abbreviations . 7
4 Applicability . 14
5 Business specifications for the long term archiving and retrieval of CAD PMI . 15
5.1 General. 15
5.2 Description of use cases for retrieval of 3D PMI entities . 16
6 Essential Information of Product and Manufacturing Information (PMI) . 16
6.1 General. 16
6.2 Dimensional tolerancing . 17
6.3 Geometric tolerances . 17
6.4 Other PMI related data (non-exhaustive) . 18
6.5 User Defined Attributes associated to CAD 3D Geometry . 18
6.6 Saved view . 19
6.7 Associativity between the shape and PMI . 19
7 Definition of Core Model for Product and Manufacturing Information (PMI) . 19
8 Verification rules for Product and Manufacturing Information . 21
8.1 General. 21
8.2 Level of Verification . 21
9 Validation rules of Product and Manufacturing Information . 21
9.1 General. 21
9.1.1 Unicode String Validation Properties per PMI entity . 22
9.1.2 Application of Unicode String Validation Properties. 22
9.2 Levels of Validation . 22
9.3 Comparison of the PMI Validation Properties (PMIVP) . 24
9.4 Results of the Validation . 24
9.4.1 At the ingest process (qualify) . 24
9.4.2 At the retrieval process (comparison) . 25
9.4.3 Status information . 25
9.4.4 Validation reports . 25
Bibliography . 26

European foreword
This document (EN 9300-120:2023) has been prepared by the Aerospace and Defence Industries
Association of Europe - Standardization (ASD-STAN).
After enquiries and votes carried out in accordance with the rules of this Association, this document has
received the approval of the National Associations and the Official Services of the member countries of
ASD-STAN, prior to its presentation to CEN.
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 2024, and conflicting national standards shall be
withdrawn at the latest by May 2024.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
Any feedback and questions on this document should be directed to the users’ national standards body.
A complete listing of these bodies can be found on the CEN website.
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, Republic of North
Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and the United
Kingdom.
Introduction
This document was prepared jointly by AIA, ASD-STAN, PDES, Inc., and the prostep ivip Association. The
prostep ivip Association is an international non-profit association in Europe. For establishing leadership
in IT-based engineering it offers a moderated platform to its nearly 200 members from leading industries,
system vendors and research institutions. Its product and process data standardization activities at
European and worldwide levels are well known and accepted. The prostep ivip Association sees this
standard and the related parts as a milestone of product data technology.
PDES, Inc. is an international non-profit association in USA. The mission of PDES, Inc. is to accelerate the
development and implementation of the ISO 10303 series, enabling enterprise integration and PLM
interoperability for member companies. PDES, Inc. gathers members from leading manufacturers,
national government agencies, PLM vendors and research organizations. PDES, Inc. supports this
standard as an industry resource to sustain the interoperability of digital product information, ensuring
and maintaining authentic longevity throughout their product lifecycle.
Readers of this standard should note that all standards undergo periodic revisions and that any reference
made herein to any other standard implies its latest edition, unless otherwise stated. The Standards will
be published under two different standards organizations using different prefixes. ASD-STAN will publish
the standard under the number EN 9300–xxx. AIA will publish the standard under the number NAS9300–
xxx. The content in the EN 9300 and NAS9300 documents will be the same. The differences will be noted
in the reference documentation (i.e. for EN 9300 Geometric Dimensioning & Tolerancing will be
referenced in ISO 1101 and ISO 16792, and for NAS9300 the same information will be referenced in
ASME Y14.5 and Y 14.41). The document formatting etc., will follow that of the respective editorial rules
of ASD-STAN and AIA.
The requirements of EN 9300-110 “CAD mechanical 3D explicit geometry information” about the
preservation of the 3D explicit shape shall apply within this document.
This document specifies the requirements for the long term digital preservation of the presentation of
Product and Manufacturing Information (PMI) with their possible links to the 3D explicit shape and
geometry of single CAD parts. The goal is to preserve this 3D information with respect to the geometry
and related PMI produced by the original CAD system, following the principles laid down in EN 9300-003
“Fundamentals and Concepts”.
The meaning of terms “Presentation” and “Representation”, specified in the EN 9300-100 “Common
concepts for Long term archiving and retrieval of CAD 3D mechanical information” is required to
understand this EN 9300 document.
1 Scope
1.1 In scope
This document is applicable to:
— the Presentation of 3D geometrical dimension and tolerance, and 3D annotation attributes;
— their possible semantic links with 3D Geometric shape;
— User Defined Attributes: that are assigned to 3D geometric entities or at the part level.
For the purpose of this document, the semantic definition is at the level that supports associative “Cross-
highlighting”, to illustrate the portion of the geometry to which a PMI element applies.
In this version, the technology used to preserve this 3D information is based on polyline and tessellated
presentation. Polyline presentation is a conversion to lines and curves of all 3D annotations by the STEP
interfaces of the CAD system, including validation properties. Tessellated presentation is a conversion to
tessellated curves and tessellated faces. The main use cases are the Certification and Product Liability of
static information, however, re-use is also possible after the deletion of previous PMI and creation of new
PMI (refer to clause 3 for definition).
1.2 Out of scope
This document does not apply to:
— machine-interpretable PMI “Representation”;
— how to preserve additional information:
— property rights;
— form features;
— machining features;
— CAD Assemblies.
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.
EN 9300 (all parts), Aerospace series — LOTAR — Long Term Archiving and Retrieval of digital technical
product documentation such as 3D, CAD and PDM data
ISO 10303-42, Industrial automation systems and integration — Product data representation and
exchange — Part 42: Integrated generic resources: Geometric and topological representation
ISO 10303-101, Industrial automation systems and integration — Product data representation and
exchange — Part 101: Integrated application resources: Draughting
ISO 10303-203, Industrial automation systems and integration — Product data representation and
exchange — Part 203: Application protocol: Configuration controlled 3D design of mechanical parts and
assemblies
ISO 10303-214, Industrial automation systems and integration — Product data representation and
exchange — Part 214 — Application protocol: Core data for automotive mechanical design processes
ISO 10303-242, Industrial automation systems and integration — Product data representation and
exchange — Part 242: Application protocol: Managed model-based 3D engineering
ISO 10303-514, Industrial automation systems and integration — Product data representation and
exchange — Part 514: Application interpreted construct: Advanced boundary representation
ISO 10303-519, Industrial automation systems and integration — Product data representation and
exchange — Part 519: Application interpreted construct: Geometric tolerances
ISO 1101, Geometrical product specifications (GPS) — Geometrical tolerancing — Tolerances of form,
orientation, location and run-out
ISO 16792, Technical product documentation — Digital product definition data practices
ASME Y14.41, Digital Product Definition Data Practices
CAx-IF Recommended Practices for the Representation and Presentation of Product Manufacturing
Information (PMI) (AP242)
CAx-IF Recommended Practices for PMI Polyline Presentation (AP203/AP214)
CAx-IF STEP Recommended Practices for User Defined Attributes
3 Terms, definitions and abbreviations
For the purposes of this document, the terms and definitions given in EN 9300-007, EN 9300-100 and the
following apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https://www.iso.org/obp
— IEC Electropedia: available at https://www.electropedia.org/
Figure 1 illustrates the terms introduced in this document:

Document is withdrawn.
Figure 1 — Hierarchy of PMI Terms
3.1
Product and Manufacturing Information (PMI)
Product and Manufacturing Information (PMI) is used in 3D Computer-aided Design (CAD) systems to
convey information about the definition of a product’s components for manufacturing, inspection and
sustainment, which supplements the geometric shape of the product. This includes, but is not limited to,
data such as dimensions, tolerances, surface finish, weld symbols, material specifications, 3D annotations
and user defined attributes. The term PMI, used by itself, relates to a certain information content within
a product definition; i. e. it indicates what information is being stored, independent from how it is being
stored
Note 1 to entry: Though PMI is generally accepted to be the generic designation, the term Geometric Dimensioning
and Tolerancing (GD&T) is the main type of PMI that is currently in focus. Other synonymously used terms are:
General Tolerances and Annotations, Annotation, Smart Dimensions, Functional Tolerancing and Annotation
(FT&A) or Geometric Product Specification (GPS). Some of these are specific to a particular CAD system. Industry
standards for defining PMI include standards such as ASME Y14.5, ASME Y14.41 and ISO 1101, ISO 16792
respectively.
3.2
Geometric Dimensioning and Tolerancing (GD&T)
Geometric Dimensioning and Tolerancing (GD&T) is a type of Product and Manufacturing Information
(PMI) that can be either computed automatically by a CAD system, or entered manually by the user. The
definitions below are additions to the terms mentioned in EN 9300-100 “Common concepts for Long term
archiving and retrieval of CAD 3D mechanical information”
Note 1 to entry: Explicit Tolerance: Any tolerance with a stated numeric value, regardless of how or where it is
applied. Explicit tolerances can be applied through general notes, flag notes, and PMI or tolerance dimensions. This
must be attributable to a specific feature, feature set and/or datum reference (e. g. position, orientation). Standard
+/− 0,03 notes may be explicit, depending on their use.
Note 2 to entry: Implicit Tolerance: Any tolerance where there is no stated value and acceptability of the feature is
defined by engineering to be through visual comparison to the appearance shown in the CAD model. Standard +/−
0,03 notes may also be implicit, depending on their use.
Note 3 to entry: Explicit Dimension: The required nominal value is stated in the CAD model so that it can be obtained
without interrogation.
Note 4 to entry: Implicit Dimension: The nominal value can only be obtained by interrogation (i. e. feature to feature
measuring) of the CAD model.
3.3
Semantic Representation
Semantic Representation designates a certain way how information is being stored; it does not relate to
the information content itself. Semantic Representation captures the meaning (intent) and relationships
(context) of a character, word, phrase, sentence, paragraph, specification, or symbol without using any of
the visual characters or constructs that are needed for a human to understand it – such as the letters,
graphical symbols, lines and arrows used on engineering drawings
Note 1 to entry: The main purpose of Semantic Representation is to facilitate automated consumption of the data,
e. g. for later re-use or for downstream applications. It applies to various types of data, such as PMI, Composite
Material Definition, and others.
EXAMPLE The Semantic Representation of a Linear Dimension includes all of the information needed to
understand the specification (the type of dimension, between which features it is specified…), without any of the
graphic components such as dimension lines and extension lines, their direction, arrowheads and the dimension
value.
Note 2 to entry: It should be noted that semantic representation is out of scope for this document. It is included as
a reference.
3.4
Presentation
Presentation designates a certain way how information is being stored; it does not relate to the
information content itself. Presentation defines the visual representation of a character, word, phrase,
sentence, paragraph, specification, or symbol in a way that is understandable by humans. Presentation is
a generic term that applies to any form of human-readable information transfer; this can for instance be
a handwritten note, an engineering drawing, or the display of a 3D CAD model on a computer screen
Note 1 to entry: The main purpose of Presentation is to facilitate human comprehension of the data, e. g. to
manufacture, inspect, assemble or maintain the product described by the data. For a correct interpretation of the
presented data, it is required that the reader is familiar with the alphabet used and the general type of information
being presented.
Note 2 to entry: In the context of 3D CAD, the term Presentation relates to elements that are visible in the display
of a 3D model and are either located (positioned) in 3D space, i. e. they rotate and move with the model, or in a fixed
2D plane. Elements of Presentation can typically by styled (e. g. coloured), organized (e. g. in specific views), and
associated with other elements of the model. Presented types of data typically are geometry (3D shapes, surfaces,
curves, points) and characters (letters, numbers, and symbols).
3.4.1
Character-based Presentation
Character-based Presentation is a type of Presentation where the conveyed information is stored as
characters (letters, numbers, and symbols). These characters are typically stored in a string variable that
can be retrieved and edited in a consuming application. The appearance of Character-based Presentation
depends on the font being used and may change if the originating system and the consuming application
use different fonts. To ensure no characters are lost from creation to consumption, the alphabet
(character encoding) used shall be specified as well
EXAMPLE In ASCII, the letter ‘A’ is stored as character code ‘0x41’ (hexadecimal).
Note 1 to entry: Character-based Presentation is often supplemented by geometric elements, such as leader lines,
curves or terminator symbols.
3.4.2
Graphic Presentation
Graphic Presentation is a type of Presentation where the conveyed information is converted to geometric
elements (lines, arcs, surfaces) by the source system in a way that preserves the exact appearance (color,
shape, positioning) of the presented information. The arrangement of these geometric elements can be
interpreted by a competent human by looking at them, while the information content is no longer directly
computer-accessible
EXAMPLE A simple graphic presentation of the letter ‘A’ is given by three straight lines. A more complex
graphic presentation could have ten straight lines and six circular arcs, but would still be recognizable as an ‘A’ to a
human familiar with the Latin alphabet. In both cases, a computer can only access the geometric definition of the
individual elements (start and end coordinates for each line), but not the fact that it is the letter ‘A’ that is being
presented.
Note 1 to entry: Graphic Presentation does not require defining the font or alphabet (character encoding) originally
used in the creation of the presented data. In the way Graphic Presentation data is stored, there is typically no
distinction between geometric elements that are visual representations of characters, and geometric elements that
are visual representations of other constructs, such as leader lines, curves or terminator symbols.
Note 2 to entry: An indirect way of accessing the information content stored as Graphic Presentation is the
application of character recognition software that will attempt to identify the original characters from the geometric
elements that make up their visual representation. Character recognition, however, has its limitations depending
on the algorithms used, the fonts and alphabet involved, and the granularity of the Graphic Presentation geometry
elements. Its results cannot be used with the same level of reliability as Character-based Presentation.
3.4.2.1
Polyline Presentation
Polyline Presentation designates a specific implementation form of Graphic Presentation that is
supported by many STEP Application Protocols, including AP203e2 (ISO 10303-203), AP214e3
(ISO 10303-214) and AP242 (ISO 10303-242). It supports all the characteristics of Graphic Presentation.
A Polyline is defined as an ordered list of 3D points, which are consecutively connected by straight line
segments. Circles and circular arcs are the only other allowed geometric elements, and can be used in
combination with Polylines. Filled areas can be defined with the aforementioned elements as boundaries
3.4.2.2
Tessellated Presentation
Tessellated Presentation designates a specific implementation form of Graphic Presentation that is has
been introduced during the development of STEP AP242 (ISO 10303-242). It supports all the
characteristics of Graphic Presentation. It is based on data model for tessellated geometry and provides
more efficient ways of storing the data, compared to Polyline Presentation. It supports curves (composed
of straight line segments) and surfaces (composed of triangles)
Note 1 to entry: his document defines long term archival and retrieval of 3D PMI using polyline and tessellated
presentation.
3.5
Saved View
A Saved View allows user to store and retrieve specific orientation and a magnification factors of a model
(ref. ASME Y14.41 and ISO 16792)

Figure 2 — Illustration of the creation of views from the 3D definition
3.6
Cross-highlight
This is functionality in a CAD Viewer or a CAD system based on the associativity between 3D PMI and the
related shape, which allow highlighting of all related shape entities after selection of the 3D annotations
or all the rela
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