Aerospace series - LOTAR -LOng Term Archiving and Retrieval of digital technical product documentation such as 3D, CAD and PDM data - Part 110: CAD mechanical 3D Explicit geometry information

This document defines the requirements on a digital archive to preserve for the long term the 3D
explicit geometry of single CAD parts. The goal is to preserve the 3D information without loss with
respect to the geometry produced by the original CAD system, following the principles laid down in
EN 9300-003 “Fundamentals and Concepts”, including the use of an open data format.
1.2 In scope
The following is in scope of this part of EN 9300:
— business specification for long term archiving and retrieval of CAD 3D explicit geometry
(see Clause 5);
— essential information of CAD 3D explicit geometry (solids, curves, surfaces, and points) to be
preserved (see Clause 6);
— data structures detailing the main fundamentals and concepts of CAD 3D explicit geometry
(see Clause 7);
— verification rules to check CAD 3D explicit geometry for consistency and data quality (see Clause 8);
— validation rules to be stored with the CAD 3D explicit geometry in the archive to check essential
characteristics after retrieval (see Clause 9).
NOTE This includes the geometrical external shape resulting from CAD disciplines 3D entities (e.g., 3D
Structural components, 3D Tubing, 3D electrical harness, 3D composite, etc.).

Luft- und Raumfahrt - LOTAR - Langzeitarchivierung und Bereitstellung digitaler technischer Produktdokumentationen beispielsweise 3D CAD und PDM Daten - Teil 110: Explizite Geometrie

1.1   Einleitung
Dieses Dokument legt die Anforderungen an ein digitales Archiv fest, um langfristig die explizite 3D Geome¬trie einzelner CAD-Teile aufzubewahren. Das Ziel besteht in der verlustfreien Aufbewahrung der 3D Infor¬mationen über die vom ursprünglichen CAD-System erstellte Geometrie nach den in EN 9300 003 "Grund¬lagen und Konzepte" festgelegten Grundsätzen, einschließlich der Verwendung eines offenen Datenformats.
1.2   Im Anwendungsbereich
Folgendes liegt im Anwendungsbereich dieser Norm der Reihe EN 9300:
-   betriebliche Spezifikation zur Langzeit-Archivierung und -Bereitstellung von expliziten 3D CAD-Geome¬trien (siehe Abschnitt 5);
-   essentielle Informationen expliziter 3D-CAD-Geometrien (Festkörper, Kurven, Flächen und Punkte), die aufzubewahren sind (siehe Abschnitt 6);
-   Datenstrukturen, die detailliert die wichtigsten Grundlagen und Konzepte expliziter 3D-CAD-Geome-trien angeben (siehe Abschnitt 7);
-   Verifizierungsregeln zur Überprüfung der expliziten 3D-CAD-Geometrie auf Einheitlichkeit und Daten¬qualität (siehe Abschnitt 8);
-   Validierungsregeln, die mit der expliziten 3D-CAD-Geometrie im Archiv zu speichern sind, um die wesentlichen Merkmale nach der Bereitstellung zu überprüfen (siehe Abschnitt 9).
ANMERKUNG   Dazu gehört die geometrische Außenform, die sich aus 3D-Entitäten der CAD-Disziplinen ergibt (z. B. 3D-Statikbauteile, 3D-Rohrleitungen, 3D-Leitungsbündel, 3D-Verbundwerkstoffe usw.).
1.3   Außerhalb des Anwendungsbereichs
Folgendes liegt außerhalb des Anwendungsbereichs dieser Norm der Reihe EN 9300:
-   die formale Definition von Validierungs- und Verifizierungsregeln zur Überprüfung der expliziten 3D Geometrie im Hinblick auf Einheitlichkeit und Datenqualität unter Verwendung einer maschinen-lesbaren Syntax;
-   implizite oder parametrische Geometrie;
-   Geometrische Dimensionierung und Tolerierung (en: Geometric Dimensioning & Tolerancing, GD&T), Produkt- & Ferti¬gungsinformationen (en: Product & Manufacturing Information, PMI);
-   Baugruppenstrukturen;
-   Darstellung der expliziten Geometrie.

Série aérospatiale - LOTAR - Archivage long terme et récupération des données techniques produits numériques telles que CAD 3D et PDM - Partie 110 : Archivage long terme et récupération des informations CAO

1.1   Introduction
Le présent document définit les exigences s'appliquant sur une archive numérique pour la conservation à long terme de la géométrie 3D explicite de pièces uniques en CAO. L'objectif étant de conserver les informations 3D sans perte par rapport à la modélisation créée par le système de CAO d'origine, en suivant les principes énoncés dans l'EN 9300-003 « Fondamentaux et concepts », y compris l'utilisation d'un format de données ouvert.
1.2   Champ d'application
L'EN 9300 traite des points suivants :
-   les spécifications commerciales pour l'archivage long terme et la récupération de la géométrie 3D explicite en CAO (voir l’Article 5) ;
-   les informations essentielles de la géométrie 3D explicite en CAO (solides, courbes, surfaces et points) à conserver (voir l’Article 6) ;
-   les structures de données détaillant les fondamentaux et concepts principaux de la géométrie 3D explicite en CAO (voir l’Article 7) ;
-   les règles de vérification de la géométrie 3D explicite en CAO, pour contrôle de cohérence et de qualité des données (voir l’Article 8);
-   les règles de validation à stocker avec la géométrie 3D explicite en CAO dans l'archive, afin de vérifier les caractéristiques essentielles après récupération (voir l’Article 9).
NOTE   Cela inclut la forme géométrique externe résultant des entités 3D des disciplines de CAO (par exemple, composants structurels 3D, tubage 3D, faisceau électrique 3D, composite 3D, etc.).
1.3   Hors champ d’application
L'EN 9300 ne traite pas des points suivants :
-   la définition formelle des règles de validation et de vérification, afin de vérifier la cohérence et la qualité des données de la géométrie 3D explicite à l'aide d'une syntaxe lisible par machine ;
-   la géométrie implicite ou paramétrique ;
-   le Dimensionnement et Tolérancement Géométrique (GD & T), les Données de fabrication des produits (PMI) ;
-   les structures d'assemblage ;
-   la présentation de la géométrie explicite.

Aeronavtika - LOTAR - Dolgotrajno arhiviranje in iskanje digitalne tehnične dokumentacije o izdelkih, kot so podatki o 3D, CAD in PDM - 110. del: CAD mehanske 3D eksplicitne informacije o geometriji

Ta dokument določa zahteve digitalnega arhiva za dolgotrajno shranjevanje 3D eksplicitne geometrije posameznih delov CAD. Cilj je ohraniti 3D informacije brez izgub podatkov glede na geometrijo, ki jo proizvede prvotni sistem CAD, v skladu z načeli, določenimi v standardu EN 9300-003 »Osnove in pojmi«, vključno z uporabo odprte oblike zapisa podatkov.
Na področje uporabe tega dela standarda EN 9300 sodi naslednje:
– poslovna specifikacija za dolgotrajno arhiviranje in iskanje CAD 3D eksplicitne geometrije (glejte točko 5);
– osnovne informacije CAD 3D eksplicitne geometrije (liki, krivulje, površine in točke) za arhiviranje (glejte točko 6);
– podatkovne strukture za podroben opis glavnih osnov in pojmov CAD 3D eksplicitne geometrije (glej točko 7);
– preverjanje pravil za preverjanje CAD 3D eksplicitne geometrije glede doslednosti in kakovosti podatkov (glejte točko 8);
– pravila ocenjevanja, ki bodo shranjena v arhivu skupaj s CAD 3D eksplicitno geometrijo za preverjanje osnovnih značilnosti po iskanju (glejte točko 9).
OPOMBA To vključuje geometrijsko zunanjo obliko, ki je posledica 3D entitet na področjih CAD (npr. 3D strukturne komponente, 3D ocevje, 3D električna napeljava, 3D kompozit itd.).

General Information

Status
Published
Publication Date
03-Sep-2018
Technical Committee
Current Stage
6060 - National Implementation/Publication (Adopted Project)
Start Date
26-Jul-2018
Due Date
30-Sep-2018
Completion Date
04-Sep-2018

Buy Standard

Standard
SIST EN 9300-110:2018 - BARVE na PDF-str 16,31,32,33,41,42,43. Na naslovnici manjka en ICS
English language
42 pages
sale 10% off
Preview
sale 10% off
Preview

e-Library read for
1 day

Standards Content (sample)

SLOVENSKI STANDARD
SIST EN 9300-110:2018
01-oktober-2018
$HURQDYWLND/27$5'ROJRWUDMQRDUKLYLUDQMHLQLVNDQMHGLJLWDOQHWHKQLþQH
GRNXPHQWDFLMHRL]GHONLKNRWVRSRGDWNLR'&$'LQ3'0GHO&$'
PHKDQVNH'HNVSOLFLWQHLQIRUPDFLMHRJHRPHWULML
Aerospace series - LOTAR -LOng Term Archiving and Retrieval of digital technical
product documentation such as 3D, CAD and PDM data - Part 110: CAD mechanical 3D
Explicit geometry information
Luft- und Raumfahrt - LOTAR - Langzeitarchivierung und Bereitstellung digitaler

technischer Produktdokumentationen beispielsweise 3D CAD und PDM Daten - Teil 110:

Explizite Geometrie
Série aérospatiale - LOTAR - Archivage long terme et récupération des données

techniques produits numériques telles que CAD 3D et PDM - Partie 110 : Archivage long

terme et récupération des informations CAO
Ta slovenski standard je istoveten z: EN 9300-110:2018
ICS:
01.110 7HKQLþQDGRNXPHQWDFLMD]D Technical product
L]GHONH 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
SIST EN 9300-110:2018 en,fr,de

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

---------------------- Page: 1 ----------------------
SIST EN 9300-110:2018
---------------------- Page: 2 ----------------------
SIST EN 9300-110:2018
EN 9300-110
EUROPEAN STANDARD
NORME EUROPÉENNE
June 2018
EUROPÄISCHE NORM
ICS 01.110; 35.240.30; 49.020
English Version
Aerospace series - LOTAR -LOng Term Archiving and
Retrieval of digital technical product documentation such
as 3D, CAD and PDM data - Part 110: CAD mechanical 3D
Explicit geometry information

Série aérospatiale - LOTAR - Archivage long terme et Luft- und Raumfahrt - LOTAR - Langzeit-Archivierung

récupération des données techniques produits und -Bereitstellung digitaler technischer

numériques telles que 3D, CAO et PDM - Partie 110 : Produktdokumentationen, wie zum Beispiel von 3D-,

Données de géométrie 3D explicite en CAO mécanique CAD- und PDM-Daten - Teil 110: Eindeutige 3D-

Geometrieinformationen für mechanische CAD-Teile
This European Standard was approved by CEN on 25 September 2017.

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: Rue de la Science 23, B-1040 Brussels

© 2018 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 9300-110:2018 E

worldwide for CEN national Members.
---------------------- Page: 3 ----------------------
SIST EN 9300-110:2018
EN 9300-110:2018 (E)
Contents Page

European foreword ....................................................................................................................................................... 3

Foreword .......................................................................................................................................................................... 4

1 Scope .................................................................................................................................................................... 5

2 Normative references .................................................................................................................................... 6

3 Terms and definitions ................................................................................................................................... 6

4 Applicability ...................................................................................................................................................... 7

5 Business specifications for the long term archiving and retrieval of CAD mechanical

3D explicit geometry information ............................................................................................................. 7

6 Essential information of explicit geometry ........................................................................................ 10

7 Definition of core model for an explicit geometry ........................................................................... 11

8 Verification rules of explicit geometry ................................................................................................. 11

9 Validation rules of an explicit geometry .............................................................................................. 16

(informative) Description of use cases for long term archiving and retrieval of CAD

3D explicit geometry ................................................................................................................................... 20

(informative) Definition of explicit 3D shape as advanced boundary representation

according ISO 10303-514 .......................................................................................................................... 26

(informative) Definition of tessellated 3D shape according ISO 10303-42 .......................... 29

(informative) Recommended verification rules level 1 and level 2 ........................................ 32

(informative) Illustration of qualification reports ........................................................................ 36

(informative) Illustration of CAD 3D geometry validation properties ................................... 37

---------------------- Page: 4 ----------------------
SIST EN 9300-110:2018
EN 9300-110:2018 (E)
European foreword

This document (EN 9300-110:2018) 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 Standard has

received the approval of the National Associations and the Official Services of the member countries of

ASD, 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 December 2018, and conflicting national standards

shall be withdrawn at the latest by December 2018.

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.

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.
---------------------- Page: 5 ----------------------
SIST EN 9300-110:2018
EN 9300-110:2018 (E)
Foreword

This standard 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 ISO 10303, 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 NAS 9300–xxx. The content in the EN 9300 and NAS 9300 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 NAS 9300 the same

information will be referenced in ASME Y14.5M and Y 14.41). The document formatting etc., will follow

that of the respective editorial rules of ASD-STAN and AIA.
---------------------- Page: 6 ----------------------
SIST EN 9300-110:2018
EN 9300-110:2018 (E)
1 Scope
1.1 Introduction

This document defines the requirements on a digital archive to preserve for the long term the 3D

explicit geometry of single CAD parts. The goal is to preserve the 3D information without loss with

respect to the geometry produced by the original CAD system, following the principles laid down in

EN 9300-003 “Fundamentals and Concepts”, including the use of an open data format.

1.2 In scope
The following is in scope of this part of EN 9300:

— business specification for long term archiving and retrieval of CAD 3D explicit geometry

(see Clause 5);

— essential information of CAD 3D explicit geometry (solids, curves, surfaces, and points) to be

preserved (see Clause 6);

— data structures detailing the main fundamentals and concepts of CAD 3D explicit geometry

(see Clause 7);

— verification rules to check CAD 3D explicit geometry for consistency and data quality (see Clause 8);

— validation rules to be stored with the CAD 3D explicit geometry in the archive to check essential

characteristics after retrieval (see Clause 9).

NOTE This includes the geometrical external shape resulting from CAD disciplines 3D entities (e.g., 3D

Structural components, 3D Tubing, 3D electrical harness, 3D composite, etc.).
1.3 Out of scope
The following is outside the scope of this part of EN 9300:

— the formal definition of validation and verification rules to check 3D explicit geometry for

consistency and data quality using a machine-readable syntax;
— implicit or parametric geometry;

— Geometric Dimensioning & Tolerancing (GD&T), Product & Manufacturing Information (PMI);

— assembly structures;
— presentation of explicit geometry.
---------------------- Page: 7 ----------------------
SIST EN 9300-110:2018
EN 9300-110:2018 (E)
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 1101:2012, Geometrical product specifications (GPS) — Geometrical tolerancing — Tolerances of

form, orientation, location and run-out

ISO 2768-1:1989, General tolerances — Part 1: Tolerances for linear and angular dimensions without

individual tolerance indications (First Edition)

ISO 2768-2:1989, General tolerances — Part 2: Geometrical tolerances for features without individual

tolerance indications (First Edition)

ISO 10303-42:2003, Industrial automation systems and integration — Product data representation and

exchange — Part 42: Integrated generic resource: Geometric and topological representation

ISO 10303-59:2014, Industrial automation systems and integration — Product data representation and

exchange — Part 59: Integrated generic resource — Quality of product shape data

ISO 10303-203:2011, Industrial automation systems and integration — Product data representation and

exchange — Part 203: Application protocol: Configuration controlled 3D design of mechanical parts and

assemblies

ISO 10303-214:2010, Industrial automation systems and integration — Product data representation and

exchange — Part 214: Application protocol: Core data for automotive mechanical design processes

ISO 10303-242:2014, Industrial automation systems and integration — Product data representation and

exchange — Part 242: Application protocol: Managed model-based 3D engineering

ISO 10303-514:1999, Industrial automation systems and integration — Product data representation and

exchange — Part 514: Application interpreted construct: Advanced boundary representation

ISO 16792:2006, Technical product documentation — Digital product definition data practices

ASME Y14.5:2009, Dimensioning and Tolerancing
ASME Y14-41:2012, Digital Product Definition Data Practices
FAA Part 21, Certification for Products, Parts & PMA
3 Terms and definitions

For the purposes of this document, the terms and definitions given in EN 9300-007 and EN 9300-100

apply.

ISO and IEC maintain terminological databases for use in standardization at the following addresses:

• IEC Electropedia: available at http://www.electropedia.org/
---------------------- Page: 8 ----------------------
SIST EN 9300-110:2018
EN 9300-110:2018 (E)
• ISO Online browsing platform: available at http://www.iso.org/obp
4 Applicability
Refer to applicability of EN 9300-001, Clause 4.
5 Business specifications for the long term archiving and retrieval of CAD
mechanical 3D explicit geometry information
5.1 Introduction

General specifications for long term archiving of CAD mechanical design information are described in

EN 9300-100, in the clause “Fundamentals and concepts for long term archiving of CAD 3D mechanical

information”.

According to the clause “5.1 Different generations of CAD systems and associated methods of design”,

there are several methods of design:

— The first generation of CAD design method allowed the engineer to digitally create a 2D drawing

(without a 3D model). The essential information as well as the regulatory authority of the design

intent is represented by the 2D drawing.

— The second generation of CAD design method is based primarily on the use of 3D models with the

output being both 2D representation (drawings) and a 3D CAD dataset to drive CAM/CAI. The

regulatory authority of the design intent is represented by the 2D drawing.

— The third generation of CAD design method is based on the use of parametric and relational design.

The essential information as well as the regulatory authority of the design intent is represented by

the 3D model.
---------------------- Page: 9 ----------------------
SIST EN 9300-110:2018
EN 9300-110:2018 (E)
Figure 1 — Illustration of the major generations of CAD systems

EN 9300-110 part specifies long term archiving for CAD mechanical 3D explicit geometry generated in

CAD systems of the second and third generation.

5.2 Description of use cases for retrieval of CAD mechanical 3D explicit geometry

Use cases for long term archiving and retrieval of CAD mechanical are used to verify that the

specifications meet the business requirements, to identify any gaps that occur over time, and to fix

them. This is illustrated in Figure 2, extracted from EN 9300-100 Figure 2: “Links between Use Cases,

essential information and EN 9300-1xx parts”.
---------------------- Page: 10 ----------------------
SIST EN 9300-110:2018
EN 9300-110:2018 (E)
Figure 2 — Links between use cases, essential information and EN 9300-1xx parts

This clause sums up general requirements common to the aerospace industries, for the preservation of

the 3D external shape of the product. These requirements should be reviewed and adapted by each

company, according to its products and its business practices.

After retrieval from the long term archiving system, the CAD 3D information may be not exactly the

same as the original. This may result, for example, from the changes in mathematical representation of

the CAD modeller (“change of generation of CAD systems”), or from the evolution of their internal data

models through successive versions. The objective is to demonstrate that the process still preserves the

essential information for the 3D shape of the product, as defined by the original CAD system the

moment that the CAD information was released.

The type of CAD representation to be preserved differ according to the use cases (see EN 9300-100

Figure 4: Links between use cases, essential information and EN 9300-1xx parts). In the same way, the

tolerance thresholds for the verification rules and geometric validation properties are related to the

different use cases and to the specific requirements of each company. Such thresholds will not be

normatively defined in this standard, but values will be proposed in associated recommended practices.

Such tolerances depend on the precision of the CAD modeller; it is assumed that the precisions of the

modellers will increase overtime. They are also related to the categories of parts and to their functions.

As mentioned in the EN 9300-002, there are 4 main use cases for long-term archiving and retrieval of

CAD 3D exact geometry, and its complementary 2D drawings:

— documentation of aerospace & defence product design for regulatory and contractual compliance;

— aerospace & defence industry incident investigation (product liability);
— design re-use – product modification;
---------------------- Page: 11 ----------------------
SIST EN 9300-110:2018
EN 9300-110:2018 (E)
— product lifecycle support and disposal.

These use cases are detailed in the context of long term preservation of CAD mechanical 3D explicit

geometry information.
For more information, see Annex A.
5.3 Description of file content
— Scenario 1: part file with exact geometry only;
— Scenario 2: part file with tessellated geometry only;
— Scenario 3: part file with exact and tessellated geometry;

— Scenario 4: part file containing an assembly mixing exact and tessellated geometry (example:

Equipment internal geometry, see EN 9300-115 and EN 9300-125).
6 Essential information of explicit geometry

Essential information of 3D explicit geometry, captured in archive files, is defined as:

— the exact boundary representation shape of a single part within free tolerances of manufacturing

(e.g. according to ISO 2768 general tolerances);
— the tessellated boundary representation shape;
— the exact representation of curves;
— the tessellated representation of curves;
— the exact representation of surfaces;
— the tessellated representation of surfaces;
— the representation of points.

The EN 9300 standards shall be applied to any additional information not covered by this standard.

---------------------- Page: 12 ----------------------
SIST EN 9300-110:2018
EN 9300-110:2018 (E)
7 Definition of core model for an explicit geometry

To preserve the essential information of explicit 3D geometry the shape should be represented at

nominal size precisely and completely within the defined tolerances independent of tool specific

generation functions for geometry. Therefore a boundary representation as an accumulative topological

and geometric volume model has been chosen as core model for this part of EN 9300.

This core model is defined by ISO 10303-514 (advanced boundary representation) and ISO 10303-42

(geometric and topological representation). This representation is used by ISO 10303-203

(configuration controlled 3D design of mechanical parts and assemblies) CC08, ISO 10303-214 (core

data for automotive mechanical design processes) CC02 and ISO 10303-242 (managed model based 3D

Engineering). Therefore STEP physical files meeting ISO 10303-203 CC08 or ISO 10303-214 CC02 or

ISO 10303-242 may be used for the ingest of explicit geometry. The descriptive information of the AIP

shall document the versions of both EN 9300-110 and ISO 10303 application protocol that are basis for

the AIP .

Other geometric information or information related to geometry such as design history, layer

information, auxiliary geometry or technical attributes like roughness or tolerances as modelled in

typical CAD systems may be maintained together with the 3D explicit geometry within the same STEP

file, assuming that this information can be represented by the chosen application protocol of ISO 10303.

In this case additional validation properties and verification rules defined in the respective parts of

EN 9300 should be applied to ensure the preservation of this additional information.

8 Verification rules of explicit geometry
8.1 Introduction

As described in “Authentication and Verification” (EN 9300-005), verification is one of the two basic

qualification methods to reduce the risk of losing essential information during long term archiving.

The verification of the source and the target CAD model are not required in this standard, but the

quality of the exported file in the archival format is strongly dependant of the quality of the source CAD

model, and lack of verification creates a risk that the retrieval process will fail.

The verification for 3D explicit geometry described in this clause concerns only the archival file during

the ingest process (EN 9300-012).

To improve the longevity of the archive, companies may decide to add new verification rules and to

check a selection of the archived files. In this case, the company may decide to archive the new

verification report, and according to the result, to carry out the appropriate action to ensure the long

term preservation of the CAD archived information.

If a verification of the native target CAD model is implemented in the retrieval process (EN 9300-014),

the CAD model shall pass the validation process before the model will be fully acceptable. Verification

process is required to minimize the risk of data loss or unacceptable change between archival and

retrieval. This process shall be applied to the STEP file during archival ingestion, to the STEP file after any

archival preservation conversion. It is strongly recommended that this process is also applied to the target

CAD model after STEP import.

AIP: Archive Information Package. (see part EN 9300-007 “Terms and definitions”).

---------------------- Page: 13 ----------------------
SIST EN 9300-110:2018
EN 9300-110:2018 (E)
8.2 Level of verification

Conversion of CAD models between different formats may lead to the loss of geometrical and

topological elements.

To minimize the risk of such kind of problems, companies shall choose one of the following three levels

of verification:

— verification level 0, no verification, which entails accepting the maximum risk of failure at retrieval;

— verification level 1, with an controlled risk, and using list of verification rules defined below;

— verification level 2, with a minimum risk by the use of verification level 1 rules, plus additional

verification rules defined by the company.

For exact solid and surface, the rules for the verification level 1 are a subset of the rules defined in the

SASIG PDQ, ISO 10303-59, which provides a definition for each rule, an illustration of the defects

detected by the rule, and, where possible, a method to fix the defects.

For tessellated solid and surface, the verification rule level 1 can consist of a check such as a watertight

tessellation.

For verification level 2, companies may check using their own verification rules, see Annex D

(informative) – Recommended verification rules level 1 and level 2.

For example 1, multiple identical elements (points, curves, surfaces) can be problematic for some

business case, and the distance between two identical elements need to be within a given tolerance that

may change from one system to another system (e.g., change of generation of CAD modellers).

For example 2, specific rules for the verification of the structure of the CAD model (colour and layers)

may be added.

Some rules are parameterised by acceptance thresholds. For the long term retention of 3D explicit

geometry, the verification level 1 shall be applied with appropriate thresholds in the ingest process. For

the retrieval process, this is not required.
8.3 Geometrical verification rules and appropriate thresholds
8.3.1 Verification rules

Verification is applied to the B-REP-STEP-file according to of ISO 10303-514 and ISO 10303-42.

The verification rules level 1 shall be applied by each company. These are required to ensure a high rate

of success for the import process of the archival file, and for retrieval of the shape of the parts without

significant change.

The method used to define the verification rules (both level 1 and level 2), and the initial set of the

recommended verification rules for level 1 can be found in the Annex D.

The set of verification rules may change over the time following successive upgrades of the CAD

systems. To add new verification rules, the method in Annex D should be used.
---------------------- Page: 14 ----------------------
SIST EN 9300-110:2018
EN 9300-110:2018 (E)
Two ways to verify the quality of the STEP files have been identified:
— using a STEP checker which includes its own geometry kernel;
— using a CAD checker after import of the STEP file into a CAD system.

If a checker does not implement the verification rules level 1, a mapping with its own verification rules

shall be documented and a qualification provided with appropriate test cases.

Following the change of CAD system and its STEP interfaces, the list of verification rules may be adapted

using an adequate method, as described in Annex D. Otherwise the list of verification rules level 1

should be applied.

A company may remove a verification rule from level 1 if it is demonstrated and documented that the

users' methods or the operational CAD system does not allow the quality defects detected by the rule to

occur in STEP files.

Before implementing the ingest processes, it is recommended that an analysis takes place of the CAD

system interfaces export options and their consequences for the contents of STEP files. For example, an

option to export or not the entities placed in a no show mode may have an impact on verification.

8.3.2 Evaluation of the values of thresholds

Verification may be done by checkers, which shall be compliant with the rules for the verification level 1

and level 2.

Following the precision of the parts, the quality of the computation, and the precision of the source CAD

systems, a threshold per types of CAD parts and per rule may be defined.

NOTE As a result, the thresholds for each verification rule cannot be standardized. The thresholds in Annex D

are informative.

If required for particular rules and categories of CAD parts, a second threshold may be defined to

indicate a “warning” rather than a failure.

The example below shows that for the same rule, the “Edge Gap” thresholds are significant for import

success:

— When there are only negligible gaps between connected edges in a STEP model, receiving CAD

systems are able to import the geometry with negligible shape changes, including maintaining the

BREP solid definition, see Figure 3 “No_Edge_Gap”.

— When the gap between connected edges is too large in the STEP model, it is usually too difficult for

the receiving CAD system to close it sufficiently to create a solid model. In this case, the model on the

right was imported as an open shell, see Figure 4: “Unacceptable_Edge_Gap”.
---------------------- Page: 15 ----------------------
SIST EN 9300-110:2018
EN 9300-110:2018 (E)
Figure 3 — No Edge Gap
Figure 4 — Unacceptable Edge Gap

This implies that the checker should be qualified against the verification rules and thresholds, and all

changes in this tool shall be approved. This qualification shall include test cases with known defects

after import of the archival files into different geometry kernels. The method for qualification is out of

the scope of this standard. A qualification of the STEP file checker by Export and Import in the same

CAD system is not enough because the same error may occur consistently.
---------
...

Questions, Comments and Discussion

Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.