Strategies for the Curation of CAD Engineering Models 4th International Digital Curation Conference "Radical Sharing: Transforming Science?“ 1 st -3 rd December 2008 Edinburgh, UK Manjula Patel, Alexander Ball, Lian Ding UKOLN, DCC, IdMRC University of Bath, UK

Overview Need for long-term data retention and curation in engineering Product-Service Paradigm Product Lifecycle Management (PLM) Switch to creating engineering data digitally Importance of Computer Aided Design (CAD) models Specific curation challenges Prototypes LiMMA: Lightweight Models with Multilayered Annotation RRoRIfE: Registry/Repository of Representation Information of Engineering

Need for long-term data retention and curation in engineering

Product-Service Paradigm

Product Lifecycle Management (PLM)

Switch to creating engineering data digitally

Importance of Computer Aided Design (CAD) models

Specific curation challenges

Prototypes

LiMMA: Lightweight Models with Multilayered Annotation

RRoRIfE: Registry/Repository of Representation Information of Engineering

Product-Service Paradigm Products are being purchased and sold as services rather than artefacts Commitment to provide support for lifetime of product –could be 50 years or even longer!

Products are being purchased and sold as services rather than artefacts

Commitment to provide support for lifetime of product –could be 50 years or even longer!

Product Lifecycle Management Management of product data across an (extended) enterprise over the entire lifecycle of a product Gained prominence over the last decade or so Globalisation has led to collaborative practices Product development, manufacture and maintenance occur in a geographically distributed and networked environment Product data dispersed over many organisations and locations

Management of product data across an (extended) enterprise over the entire lifecycle of a product

Gained prominence over the last decade or so

Globalisation has led to collaborative practices

Product development, manufacture and maintenance occur in a geographically distributed and networked environment

Product data dispersed over many organisations and locations

PLM Information Flows Conceptualisation; Design Organisation; Design; Evaluation; Manufacture & Delivery; Sales & Distribution; Service & Support; Decommission & Disposal Pre-existing information & experience Design team Design team In service In service Upgrade Production In service In service Upgrade Production Design Product 1 Product 2 Partners Regulators Customers

Product Lifecycle Management (1) Efficient capture, representation, organisation, retrieval and reuse of product data over its entire life Sharing of product information between many distributed organisations Issues relating to security of information and Intellectual Property Large variety of data, information and knowledge Structured e.g. Geometric models and databases; test data (photographs, images, load diagrams, finite element analyses); manufacturing process plans; assembly plans; production and manufacturing logs; maintenance and service data; Unstructured e.g. email; minutes of meetings; design reviews; contracts Tacit knowledge e.g. design rationale; lessons learnt; procedures and processes Exchange of information between heterogeneous computer systems CAD/CAE/CAM (Computer Aided Design/Engineering/Manufacture) ERP/CRM/SCM ( Enterprise Resource Planning/ Customer Relationship Management/ Supply Chain Management)

Efficient capture, representation, organisation, retrieval and reuse of product data over its entire life

Sharing of product information between many distributed organisations

Issues relating to security of information and Intellectual Property

Large variety of data, information and knowledge

Structured e.g. Geometric models and databases; test data (photographs, images, load diagrams, finite element analyses); manufacturing process plans; assembly plans; production and manufacturing logs; maintenance and service data;

Unstructured e.g. email; minutes of meetings; design reviews; contracts

Tacit knowledge e.g. design rationale; lessons learnt; procedures and processes

Exchange of information between heterogeneous computer systems

CAD/CAE/CAM (Computer Aided Design/Engineering/Manufacture)

ERP/CRM/SCM ( Enterprise Resource Planning/ Customer Relationship Management/ Supply Chain Management)

Product Lifecycle Management (2) Different stages of PLM require different subsets and interpretations of the same data i.e. different viewpoints e.g. Manufacturing engineers need machining features and tolerances Marketing staff need a final visualisation of the product Data needs to be trustworthy, reliable and accurate for use in downstream processes Vital to actively manage all information and data related to a product Legal issues e.g. accident investigation; failure analysis; mergers and acquisitions; patent infringement Operational support e.g. maintenance; replenishment of spare parts; recycling; disposal Product development and management e.g. tracing design rationale; design reuse; customisation and upgrade; reverse engineering; test and validation Various PLM systems under development (e.g. Arena, EDS, Dassault, MatrixOne, PTC etc.) At present, no one single system capable of managing the entire product lifecycle

Different stages of PLM require different subsets and interpretations of the same data i.e. different viewpoints

e.g. Manufacturing engineers need machining features and tolerances Marketing staff need a final visualisation of the product

Data needs to be trustworthy, reliable and accurate for use in downstream processes

Vital to actively manage all information and data related to a product

Legal issues e.g. accident investigation; failure analysis; mergers and acquisitions; patent infringement

Operational support e.g. maintenance; replenishment of spare parts; recycling; disposal

Product development and management e.g. tracing design rationale; design reuse; customisation and upgrade; reverse engineering; test and validation

Various PLM systems under development (e.g. Arena, EDS, Dassault, MatrixOne, PTC etc.)

At present, no one single system capable of managing the entire product lifecycle

Curating CAD Model Data (1) Computer Aided Design (CAD) models Important in engineering practice Definitive record of product data Gradually superseding paper-based workflow Communication of design to manufacturers, builders, maintenance crews and regulatory authorities CAD software and file formats An array of commercial CAD systems e.g. AutoCAD; CATIA; ProENGINEER; SolidWorks Proliferation of CAD formats; proprietary, closed and subject to frequent change (unsuitable for data exchange as well as long-term preservation) Complex dependencies and relationships between file formats, hardware and software (processing is often tied to hardware features to improve performance) Interoperability between CAD software is virtually non-existent Economically unviable to install and run multiple CAD systems Product is likely to outlive several generations of the software used to design and create it!

Computer Aided Design (CAD) models

Important in engineering practice

Definitive record of product data

Gradually superseding paper-based workflow

Communication of design to manufacturers, builders, maintenance crews and regulatory authorities

CAD software and file formats

An array of commercial CAD systems e.g. AutoCAD; CATIA; ProENGINEER; SolidWorks

Proliferation of CAD formats; proprietary, closed and subject to frequent change (unsuitable for data exchange as well as long-term preservation)

Complex dependencies and relationships between file formats, hardware and software (processing is often tied to hardware features to improve performance)

Interoperability between CAD software is virtually non-existent

Economically unviable to install and run multiple CAD systems

Product is likely to outlive several generations of the software used to design and create it!

CAD File Formats

Curating CAD Model Data (2) CAD models comprise large volumes of data A single, simple component can be several Megabytes Complex products (e.g. cars, aircraft) can amount to several Gigabytes or even Terabytes Reducing 3D model to 2D hard-copy documentation Entails considerable information loss; also constrains reuse of data Emulating old software and hardware Heavy investment in IT support Difficulties with integration into complex and more modern workflows and systems Migration to successive proprietary formats Risk of data loss and subtle design corruption Rechecking and revalidating costs are substantial Use of open standards e.g. IGES, STEP Long timescales make it difficult to keep up with latest capabilities of CAD tools Level of support for standards is variable between tools [Extension of STEP for various stages of PLM underway] Complex and dynamic environment Difficult to reliably retrieve and trace provenance information to check reliability and quality of data Mergers, acquisitions etc.

CAD models comprise large volumes of data

A single, simple component can be several Megabytes

Complex products (e.g. cars, aircraft) can amount to several Gigabytes or even Terabytes

Reducing 3D model to 2D hard-copy documentation

Entails considerable information loss; also constrains reuse of data

Emulating old software and hardware

Heavy investment in IT support

Difficulties with integration into complex and more modern workflows and systems

Migration to successive proprietary formats

Risk of data loss and subtle design corruption

Rechecking and revalidating costs are substantial

Use of open standards e.g. IGES, STEP

Long timescales make it difficult to keep up with latest capabilities of CAD tools

Level of support for standards is variable between tools

[Extension of STEP for various stages of PLM underway]

Complex and dynamic environment

Difficult to reliably retrieve and trace provenance information to check reliability and quality of data

Mergers, acquisitions etc.

CAD Model Representations Used in Design, Manufacture and Evaluation phases of PLM Product information stored is still largely based on conventional product representations (geometry, topology) Procedural definitions e.g. CSG Explicit representation based on underlying mathematical forms e.g. B-rep Free form surface modelling e.g. NURBS or Bézier Feature-based (pre-defined parts) or parametric modelling Typical components of a CAD Model Geometry Dimensions Tolerances Materials Feature semantics Model history

Used in Design, Manufacture and Evaluation phases of PLM

Product information stored is still largely based on conventional product representations (geometry, topology)

Procedural definitions e.g. CSG

Explicit representation based on underlying mathematical forms e.g. B-rep

Free form surface modelling e.g. NURBS or Bézier

Feature-based (pre-defined parts) or parametric modelling

Typical components of a CAD Model

Geometry

Dimensions

Tolerances

Materials

Feature semantics

Model history

Challenges for CAD Models For CAD models to support information flows in PLM, they need to address: Protection of commercially sensitive information ( Intellectual Property ) Generation of viewpoint specific representations to support differing processes and users Rapid sharing of information between geographically distributed applications and users (interoperability, platform and application independence, use of standards, reduced file sizes etc.) Support for recording feedback from downstream processes Curation (recording of metadata, design rationale, open formats, Representation Information, use of standards etc.)

For CAD models to support information flows in PLM, they need to address:

Protection of commercially sensitive information ( Intellectual Property )

Generation of viewpoint specific representations to support differing processes and users

Rapid sharing of information between geographically distributed applications and users (interoperability, platform and application independence, use of standards, reduced file sizes etc.)

Support for recording feedback from downstream processes

Curation (recording of metadata, design rationale, open formats, Representation Information, use of standards etc.)

Proposed Strategy To extend a CAD model from the design stage into all the phases of a product’s lifecycle, we propose the use of: LiMMA: Lightweight Models with Multilayered Annotations Combines open, lightweight CAD models with annotations to augment geometric data with supplementary information from PLM phases RRoRIfE: A registry/repository of Representation Information for Engineering Information Supports decisions relating to migration of file formats for continuous and long-term access and reuse

To extend a CAD model from the design stage into all the phases of a product’s lifecycle, we propose the use of:

LiMMA: Lightweight Models with Multilayered Annotations

Combines open, lightweight CAD models with annotations to augment geometric data with supplementary information from PLM phases

RRoRIfE: A registry/repository of Representation Information for Engineering Information

Supports decisions relating to migration of file formats for continuous and long-term access and reuse

Lightweight CAD Formats (LWFs) Simpler formats : do not retain all the richness of a native CAD model Analogous to the notion of desiccated formats Reduced file sizes via compression techniques Platform and application independent Easier to curate and preserve Simpler and more open specifications Wider and more affordable software support Smaller files sizes support distributed exchange Only contain as much information as a particular recipient needs Variety of LWFs in current use: Universal 3D, 3D XML, JT Format, PLM XML, PRC, X3D, XGL/ZGL Each with properties better suited to some purposes than others Suitable for access, collaboration and dissemination as well as preservation Alleviate collaborative exchange, offer customised views, security of IP, application independence, reduced file sizes etc.

Simpler formats : do not retain all the richness of a native CAD model

Analogous to the notion of desiccated formats

Reduced file sizes via compression techniques

Platform and application independent

Easier to curate and preserve

Simpler and more open specifications

Wider and more affordable software support

Smaller files sizes support distributed exchange

Only contain as much information as a particular recipient needs

Variety of LWFs in current use:

Universal 3D, 3D XML, JT Format, PLM XML, PRC, X3D, XGL/ZGL

Each with properties better suited to some purposes than others

Suitable for access, collaboration and dissemination as well as preservation

Alleviate collaborative exchange, offer customised views, security of IP, application independence, reduced file sizes etc.

Multilayered Annotation Need feedback from downstream processes Augment geometric model with information from different phases of PLM Annotation allows incorporation of varied information: Design rationale, in-service data and other information useful in an iterative design process e.g. context, provenance etc. Extra information needed for a certain viewpoint Embedding of security levels to restrict access to certain partners or users “ stand-off” (vs. “in-line”) annotation Stored separately to CAD model; actual model unchanged Can be selective about which annotations are shared Same annotation can be applied to derivatives of full CAD model Use of XML for machine-processing

Need feedback from downstream processes

Augment geometric model with information from different phases of PLM

Annotation allows incorporation of varied information:

Design rationale, in-service data and other information useful in an iterative design process e.g. context, provenance etc.

Extra information needed for a certain viewpoint

Embedding of security levels to restrict access to certain partners or users

“ stand-off” (vs. “in-line”) annotation

Stored separately to CAD model; actual model unchanged

Can be selective about which annotations are shared

Same annotation can be applied to derivatives of full CAD model

Use of XML for machine-processing

LiMMA LiMMA (Lightweight Models with Multilayered Annotations) A framework for representing CAD models using LWFs with additional layers of XML-encoded Annotations Annotation layers for different viewpoints e.g. design, manufacture, service, marketing different security and access levels

A framework for representing CAD models using LWFs with additional layers of XML-encoded Annotations

Annotation layers for

different viewpoints e.g. design, manufacture, service, marketing

different security and access levels

LiMMA LiMMA (Lightweight Models with Multilayered Annotations) 1. Designers create several annotation documents, at the same time as the CAD model.

LiMMA LiMMA (Lightweight Models with Multilayered Annotations) 2. CAD model can be derived to different LWFs for different users requiring different viewpoints: e.g. PRC for manufacturing engineers; JT for assembly engineers

LiMMA LiMMA (Lightweight Models with Multilayered Annotations) 3. All users throughout the product lifecycle are able to feedback their knowledge and experiences through annotations rather than modifying the CAD model itself. e.g. service staff can provide information regarding wear and tear.

Annotation Environments Annotation interfaces in UGS NX CAD package and 3D PDF viewer Adobe Acrobat

OAIS Representation Information A wide range of LWFs with differing characteristics are available Need format appropriate not only for a particular use and view of the product, but also for long-term retention Open Archival Information System (OAIS) Reference Model Preservation and curation environment for all types of data Developed by CCSDS, published as ISO 14721:2003 Defines a functional model and an information model Representation Information is any information required to render, interpret, process and understand data e.g. Software tools for rendering and interpretation; file format specifications and references; conventions and semantics used Essential for both curation and contemporary use A planning tool - Registry/Repository of Representation Information for Engineering (RRoRIfE)

A wide range of LWFs with differing characteristics are available

Need format appropriate not only for a particular use and view of the product, but also for long-term retention

Open Archival Information System (OAIS) Reference Model

Preservation and curation environment for all types of data

Developed by CCSDS, published as ISO 14721:2003

Defines a functional model and an information model

Representation Information is any information required to render, interpret, process and understand data

e.g. Software tools for rendering and interpretation; file format specifications and references; conventions and semantics used

Essential for both curation and contemporary use

A planning tool - Registry/Repository of Representation Information for Engineering (RRoRIfE)

RRoRIfE (1) Holds two XML schemata (derived from engineering use cases) relating to: significant properties of CAD file formats e.g. 2D and 3D geometric entities; modelling history; size; compression; geometry-related metadata (e.g. tolerances, finishes) characteristics of processing software ; record of how well each property is preserved for each format conversion –None; Good; Fair; Poor Ball, Patel & Ding paper –iPRES 2008 Registry/Repository of Representation Information for Engineering

Holds two XML schemata (derived from engineering use cases) relating to:

significant properties of CAD file formats e.g. 2D and 3D geometric entities; modelling history; size; compression; geometry-related metadata (e.g. tolerances, finishes)

characteristics of processing software ; record of how well each property is preserved for each format conversion –None; Good; Fair; Poor

Ball, Patel & Ding paper –iPRES 2008

RRoRIfE (2) Characteristics of file formats and conversion tools Select a characteristic and see which format supports it Generate possible migration pathways between two formats Given a start format and significant characteristics, generate a list of suitable destination formats and conversion pathways Facilitates simple preservation planning queries:

Characteristics of file formats and conversion tools

Select a characteristic and see which format supports it

Generate possible migration pathways between two formats

Given a start format and significant characteristics, generate a list of suitable destination formats and conversion pathways

Further Work & Conclusions Further Work Develop a more integrated framework Persistent identification of geometry between native CAD formats and the LWFs derived from them RRoRIfE: accumulate a corpus of information on significant properties of file formats and characteristics of conversion tools Non-intrusive and automated capture of information in PLM Selection and appraisal of product lifecycle data Conclusions Digital curation challenges posed by PLM are significant Several tools and techniques specific to improving the robustness and sustainability of CAD file formats LiMMA: Lightweight Models with Multilayered Annotations RRoRIfE: Registry/Repository of Representation Information for Engineering information

Further Work

Develop a more integrated framework

Persistent identification of geometry between native CAD formats and the LWFs derived from them

RRoRIfE: accumulate a corpus of information on significant properties of file formats and characteristics of conversion tools

Non-intrusive and automated capture of information in PLM

Selection and appraisal of product lifecycle data

Conclusions

Digital curation challenges posed by PLM are significant

Several tools and techniques specific to improving the robustness and sustainability of CAD file formats

LiMMA: Lightweight Models with Multilayered Annotations

RRoRIfE: Registry/Repository of Representation Information for Engineering information

Questions? Thank you Manjula Patel UKOLN, University of Bath, UK [email_address] www.ukoln.ac.uk Digital Curation Centre UKOLN, University of Bath Innovative Design & Manufacturing Research Centre Knowledge and Information Management Through Life (Grand-Challenge) Project

Thank you

Manjula Patel

UKOLN, University of Bath, UK

[email_address]

www.ukoln.ac.uk