1. DPC: Designed to Last - 1  BAE SYSTEMS July 2010 All rights reserved LOTAR High Integrity CAD Data for Aerospace Sean Barker BAE SYSTEMS Advanced Technology Centre

2. DPC: Designed to Last - 2  BAE SYSTEMS July 2010 All rights reserved BAE SYSTEMS BAE Systems is the premier global defence, security and aerospace company delivering a full range of products and services for air, land and naval forces, as well as advanced electronics, security, information technology solutions and customer support services. Key Facts - 2nd largest global defence company - 107,000 highly skilled people - Global capability - Customers in over 100 countries - Annual sales exceed £22 billion - More than 100 new inventions every year

3. DPC: Designed to Last - 3  BAE SYSTEMS July 2010 All rights reserved Focus The retention of CAD models as –Retention of Business Knowledge Not –Technology for bits and bytes Key Question – How do we reliably retain detailed design knowledge encoded in CAD models? The question is about how a business uses IT to capture design knowledge, rather than IT itself

4. DPC: Designed to Last - 4  BAE SYSTEMS July 2010 All rights reserved Contents Drawings v. Models What is LOTAR? Validation and Verification Knowledge Retention

5. DPC: Designed to Last - 5  BAE SYSTEMS July 2010 All rights reserved Drawing v. Model PASSIVE, to display ACTIVE, to manipulate & query An Image tool translate bytes into pixels For a line, a CAD tool knows how to: calculate its length find the tangent calculate where it crosses another line etc Drawing Model

6. DPC: Designed to Last - 6  BAE SYSTEMS July 2010 All rights reserved Models Represent Knowledge Presentation (drawing) A set of pixels 20[W-]; W25B100W-; 98[W25BW98BW-]; W25B100W-; -W;; Rationale (knowledge) Squares: Have Symmetry Corners are stress concentrations Bad for manholes Representation (model) Ordered set of Vertices Assume algorithms for Boundaries Inside/outside Area LOTAR

7. DPC: Designed to Last - 7  BAE SYSTEMS July 2010 All rights reserved A Drawing Records, A Model Defines 200mm 150mm Drawings - Dimensions define a drawing Models - Dimensions are read from a model

8. DPC: Designed to Last - 8  BAE SYSTEMS July 2010 All rights reserved A Brief History of CAD Computer as Electronic pencil Geometry Modelling Product Modelling Part shape is modelled to produce drawings more easily Part model includes shape, materials, tolerances Manual Drawing Automated redrawing after small changes 1970's1980's1990's2000's1960's

9. DPC: Designed to Last - 9  BAE SYSTEMS July 2010 All rights reserved The Electronic Design World Functional Design Requirement Operational Use Shape Design NC Part Program input from human Optimisation result to human input from human FE Analysis result to human input from human Automated metrology result to human Design is direct input to manufacture - Drawing is not the basis of manufacture Design is direct input to inspection - Drawing is not the basis of inspection

10. DPC: Designed to Last - 10  BAE SYSTEMS July 2010 All rights reserved Contents Drawings v. Models What is LOTAR? Validation and Verification Knowledge Retention

11. DPC: Designed to Last - 11  BAE SYSTEMS July 2010 All rights reserved An Example of Generation Change

12. DPC: Designed to Last - 12  BAE SYSTEMS July 2010 All rights reserved What is LOTAR? Site web : http://www.prostep.org/lotar/http://www.prostep.org/lotar/ Joint European/US standard for best practice in long term data retention in the aerospace industry Driver for civil sector: Electronic certification by FAA and EASA

13. DPC: Designed to Last - 13  BAE SYSTEMS July 2010 All rights reserved LOTAR and Application Knowledge NOT - is the data unchanged by the repository? BUT - are BOTH the data AND the algorithms unchanged?

14. DPC: Designed to Last - 14  BAE SYSTEMS July 2010 All rights reserved LOTAR on a Page OAIS Repository LOTAR identifies use cases for CAD Assemblies, PDM, etc LOTAR adds use case quality checks to OAIS LOTAR sets use case integrity checks on recovered data

15. DPC: Designed to Last - 15  BAE SYSTEMS July 2010 All rights reserved LOTAR – Current status 1 Structure 2 Requirements (harmonised AIA ASD-STAN) 3 Fundamentals and Concepts 4-7 Other basic Parts 10-15 OAIS Processes 20 Preservation Planning 100 CAD Fundamentals 110 CAD Explicit Geometry 115 CAD 3D Assembly Structure 120 CAD 3D Explicit Geometry with PMI 200 Product Data Management Key Issued Balloted Developing

16. DPC: Designed to Last - 16  BAE SYSTEMS July 2010 All rights reserved Contents Drawings v. Models What is LOTAR? Validation and Verification Knowledge Retention

17. DPC: Designed to Last - 17  BAE SYSTEMS July 2010 All rights reserved STEP Standard for the Exchange of Product Data – ISO 10303, in many parts, since 1980's –AP 203 & AP 214 - standards for CAD –Link geometry to product meta-data –Provides Validation Properties Surface Area Volume Cloud of Points Standard will be stable over the long term Provides "hooks" for validation and verification

18. DPC: Designed to Last - 18  BAE SYSTEMS July 2010 All rights reserved Validation – Cloud of Points what comes out is what went in Example – CAD 3D models and Cloud of Points: Are points still on the surfaces and edges? Validate that the new software reads the old data correctly Image courtesy ITI & SNECMA

19. DPC: Designed to Last - 19  BAE SYSTEMS July 2010 All rights reserved Contents Drawings v. Models What is LOTAR? Validation and Verification Knowledge Retention

20. DPC: Designed to Last - 20  BAE SYSTEMS July 2010 All rights reserved Human v Computer What is the difference between the two drawings? First Angle ProjectionThird Angle Projection LOTAR preserves models – but what about the knowledge needed to understand them? In the 1940's Geoff Wallace of the Ministry of Supply at Creekmoor, Poole had a problem Spitfire parts made in the US - right-handed parts came back left-handed - why?

21. DPC: Designed to Last - 21  BAE SYSTEMS July 2010 All rights reserved Is the text simply lines on a drawing? A string of symbols? An assertion about a diameter Human v Computer - Dimensions and Tolerances What happens to the text when I move my view point? Does the leader line end at a point in space, or point to a feature? What is a feature? Image courtesy PDES Inc

22. DPC: Designed to Last - 22  BAE SYSTEMS July 2010 All rights reserved Human v Computer - Driving dimensions 50 Dimensioning is driven by design rational  555030 5530 355030 5550 10 Which dimension to shrink? 115

23. DPC: Designed to Last - 23  BAE SYSTEMS July 2010 All rights reserved Conclusions LOTAR –a business standard for long term model sustainment –the business defines the key characteristics –it is not about IT functionality The problem is sustaining models, not drawings A model is data PLUS algorithms LOTAR validates AFTER data is read by the software There are open issues that need research: –Validation –Rationale integration with models –Knowledge recovery from old data

24. DPC: Designed to Last - 24  BAE SYSTEMS July 2010 All rights reserved backup

25. DPC: Designed to Last - 25  BAE SYSTEMS July 2010 All rights reserved Life of CAD System: 10 years Time between CAD Versions: 6 months Life of Product: 70 years + time Why Sustain Data? Production CAD Obsolete CAD Forgotten Services Legal Liability Modifications 10 years2030405060 Spares Image courtesy PDES Inc