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Slide 2. Presentation Outline. ITI TranscenData introductionRequirements for effective STEP based interoperabilityObstacles to achieving effective STEP based interoperabilityExamplesStrategies and SolutionsStandardsVerificationValidationAutomationConclusions. Slide 3. ITI (International Tec
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1. Andy Chinn
Business Development Manager
TranscenData Europe Ltd
arc@transcendata.com
2. Slide 2 Presentation Outline ITI TranscenData introduction
Requirements for effective STEP based interoperability
Obstacles to achieving effective STEP based interoperability
Examples
Strategies and Solutions
Standards
Verification
Validation
Automation
Conclusions
3. Slide 3 ITI (International TechneGroup Incorporated) Background
Founded in 1983 by Dr. Jason Lemon(one of the SDRC founders)
35 years data interoperability experience
Global Presence
North America, Europe, Asia
ITI TranscenData
Product data integration & interoperability business
Products and solutions for CAD/CAM/CAE/PDM system integration
Our interoperability objective - Usable data that is fit for purpose
4. Slide 4 ITI TranscenData Experience
5. Slide 5 TranscenData Customers
6. Slide 6 Engineering Data Interoperability CAD interoperability continues to cost industry Billions of Euros
Situation is improving all the time and many success stories
The STEP standard (ISO 10303) is now widely adopted for supply chain data exchange, system and application integration
STEP continues to evolve - AP203 Edition 2
STEP is especially prominent in the aerospace and defense
Requirements exist over and above those of basic CAD interoperability
Certified data delivery (government and military)
Long term archive
Quality standards
But still plenty of failures and problems to overcome
Continually looking for improvements
Automatic and fully validated STEP based interoperability process
7. Slide 7 STEP Translation Space-Time Continuum
8. Slide 8 STEP Based Interoperability Process What could possibly go wrong?
9. Slide 9 What Could Possibly Go Wrong? Invalid or incompatible geometry exported to STEP
Errors importing models downstream
Incomplete models or invalid solids
Geometry in STEP file unsuitable for downstream applications
Unrealistic conditions can not be meshed
Unrealistic features can not be manufactured
Geometry changes during export from native CAD to STEP
Unacceptable, unintentional and undocumented changes
Geometry changes during STEP import into downstream CAD
Unacceptable, unintentional and undocumented changes
10. Slide 10 Causes of the Problems Important to note that STEP is not at fault
Dependency on CAD systems and translators
Dependency on the definitions of entities within complex CAD models and assemblies
Topology and geometry
Features
Shape and form
Different tolerances
Different complexities
Different entities supported
Handling of assemblies
Use of coordinate systems
Requirements of downstream application
11. Slide 11 Example - Unrealistic Features Short Edges, Sliver Faces and Sharp Vertex Angles
Valid CAD model but unusable in FEA and may cause downstream failures
12. Slide 12 Example - Unrealistic Features Short Edges, Sliver Faces and Sharp Vertex Angles
Valid CAD model but unusable in FEA and may cause downstream failures
13. Slide 13 Example - Complexity of Geometry Overly Complex Geometry Definitions
May be fine in the source CAD system
Potential problems
Large models
Excessive run times
Poor CAE/CAM processes
Downstream import or application failures
14. Slide 14 Example - Translator Bugs
15. Slide 15 Example - Translator Bugs
16. Slide 16 Example - Poor Modeling or CAD Errors
17. Slide 17 Different Views of CAD Model Quality
18. Slide 18 Interoperability Issues and Design Variance
19. Slide 19 Improving Interoperability Start upstream at the source of the CAD data
Standards - Implement quality standards and design practices
Implement Product Data Quality (PDQ) into model generation
Design out potential issues at source
Determine and eliminate bad practices and methodologies
Verification - Deploy upstream model quality testing
Verify models to find problems before they propagate
Repair - Address issues as part of the translation process
CAD model repair and healing technology
Communication
Producers of CAD need to understand downstream requirements
20. Slide 20 Standards - International Quality Initiatives “Product Data Quality (PDQ) Guidelines for the Global Automotive Industry”
Strategic Automotive Standards Industry Group (SASIG) Product Data Quality team
Collaboration of international automotive groups
AIAG, VDA, JAMA, GALIA, ODETTE, FCAI, AUSDEC
TranscenData technical experts are major contributors/reviewers
Documented and classified problems and standards
Document D-15 published by AIAG July 2001 (www.aiag.org)
Extension of existing standards e.g. VDA 4955 V1
70 BREP geometry and topology quality criteria
Surfaces, Curves
Models, Solids, Shells, Faces, Edge Loops and Edges
21. Slide 21 Standards - STEP Community & Model Quality ISO 10303 Part 59 “Quality of Product Shape Data”
Extend STEP to capture native geometric quality data
Based on SASIG PDQ specification
Proposed by Japan at 2004 ISO meeting
Working draft delivered at Autumn 2005 ISO meeting
CD ballot and technical review in Autumn 2006
Targeting completion in 2008 for AP203 Edition 2 (?)
ITI project work with LOTAR Part 110 Pilot Project
Derivation of rules for geometry quality suitable for LTDR
Assessing CAD model features and the impact on receiving systems
Statistical correlation study with over 5000 STEP imports and exports
Multiple CAD systems and translations
Get it right “now” for the “future”
22. Slide 22 Verification of CAD Models Verify native CAD model for downstream use before STEP export
Assess the model looking for geometrical and topological issues that can impact the interoperability process
Ensure model is in best condition for STEP based interoperability
Suitable for different receiving CAD system and downstream applications
Achieve best condition for archival and long term retrieval
23. Slide 23 Example - Design for CAE and Manufacturing Simulation approved the design based on analysis results
Manufacturing produced initial parts from native CAD model
All parts failed during final pre production testing
Caused last-minute schedule delay and retooling
24. Slide 24 Example - Design for CAE and Manufacturing
25. Slide 25 Repair - Address Issues During Translation Automatic repair of CAD models as part of the translation process to remove issues that are not easily dealt with in CAD, e.g.:
“Seamless” face splitting for CAE systems
Degenerate or discontinuous surface definitions
Usually for downstream CAE applications
26. Slide 26 Are the Native CAD and STEP Model Identical? Is the exported model a true and accurate representation of the original part file?
Of course it is!
Has the model changed during the export process?
Of course it hasn’t!
Can you to give the customer documentation to certify that the source CAD and exported STEP models are identical?
Where do I sign?
How can you be 100% certain without Validating the translation process and the STEP file?
27. Slide 27 Example - Geometry Lost in STEP for LTA
28. Slide 28 Example - Shape Change During STEP Export
29. Slide 29 Example - Shape Change During STEP Export
30. Slide 30 Example - STEP Translation Validation
31. Slide 31 Position Change on STEP Assembly Import
32. Slide 32 Position Change on STEP Assembly Import
33. Slide 33 Part Re-size During STEP Assembly Import
34. Slide 34 STEP Imports Differently in Different Systems
35. Slide 35 Validation of STEP Files is Essential Comprehensive and precise validation of models that have been exported to STEP and imported into another CAD system is essential for effective STEP based interoperability
Validate that the STEP file is a true and accurate representation
Could be for exchange today to customers, suppliers and partners
Could be for long term archival and retrieval in 50 years
Validation process and software requirements
Needs to be accurate, reliable and repeatable
Needs to support certified data delivery in aerospace
Should be suitable for process automation and PLM integration
Facilitate the storage of all validation property data in the STEP file creating a self-validating STEP file for LTDR
Independent of proprietary commercial software
36. Slide 36 Geometric Validation Properties (GVP) PDES/ProSTEP CAX Implementers Forum recommended practices for STEP model validation using mass properties
Developed in 1998 and supported by most STEP translation vendors
Extended in 2001 to include assembly part/instance GVP
Geometric Validation Properties (GVP) defined in STEP models
Model (solids and/or surfaces) volume, area and centroid
Each solid’s volume, area and centroid
Each open shell’s area and centroid
Each assembly component’s centroid
Is this GVP validation sufficient?
Incorrect validation failure (false negatives)
Accuracy differences between CAD system mass property algorithms
Incorrect validation pass (false positives)
Localized, significant geometric deviations may be overlooked by GVP
37. Slide 37 Cloud of Points (CoPs) STEP Validation ITI TranscenData and Theorem proposed an extension to the basic GVP validation
Formally accepted at CAx-IF meeting in March 2006
Precise validation by adding face sampling points, or Cloud of Points (CoPs), validation properties to a STEP file
Smooth face sampling points (face interior and smooth edges)
Sharp face sampling points (sharp or open edges)
Validation by evaluating and comparing the position of the CoPs in models translated into different formats and systems
ITI has productionised the only commercial product to fully support STEP CoPs validation
38. Slide 38 CoPs STEP Validation
39. Slide 39 Smooth sampling point deviation calculation
Sharp sampling point deviation calculation
Smooth and Sharp Sampling Points
40. Slide 40 Example of Smooth Sampling Points
41. Slide 41 Example of Sharp Sampling Points
42. Slide 42 CoPs Representation in STEP
43. Slide 43 STEP Developments for File Validation
44. Slide 44 CADIQ Product Summary Native CAD Interfaces (API)
CATIA V5, NX, Pro/ENGINEER, SolidWorks
CATIA V4, NX I-deas, CADDS 5i
Parasolid, STEP, IGES
Specialized User Interface
Rapid review of diagnostic feedback
Side-by-side viewing of quality or shape differences
Quality Diagnostics
Invalid geometry
Unrealistic features
Comparison Diagnostics
Unacceptable changes
Unintentional changes
Undocumented changes
Assembly Analysis
CATIA V4 and V5, NX, SolidWorks, STEP, Parasolid
45. Slide 45 CADIQ STEP Validation Properties Module Precise validation of part models that have been exported to STEP and imported into another CAD system
Design data delivery and Long-term archival
More than a basic point cloud comparison
Uses advanced complex face matching and topology change analysis
Intelligent sampling point distribution
User-configurable point distribution parameters
Sharp sampling points to provide accurate validation of sharp edges
Fewer sampling points and smaller STEP VP files
Generate and add validation property data to any STEP file
Removes dependence on properties in a separate, proprietary CADIQ file
Commercially available for any major CAD system and any STEP translator from any vendor
Based on several years commercial experience of translation validations with a sampling point methodology
46. Slide 46 CADIQ Sampling Point Distribution
47. Slide 47 CADIQ Sampling Point Distribution
48. Slide 48 CADIQ STEP Translation Validation
49. Slide 49 Validated and Certified STEP Data Delivery Verify native model for downstream reuse
Validate that STEP export has equivalent quality and shape
Validate that STEP import has equivalent quality and shape
50. Slide 50 Validated 3D Long Term Archive Process Verify native CAD model for downstream reuse
Validate the STEP export has equivalent quality and shape and add validation properties to the STEP file
Validate the STEP import has equivalent quality and shape
51. Slide 51 Verification and Validation for CAE and CAM
52. Slide 52 Different Validation Technologies
53. Slide 53
54. Slide 54 The Future - More Than Geometry Validation Collaboration Model Validation
CAD to 3D PDF and JT
Assembly Structure Validation
Duplicate instances, interferences, narrow spaces and Structure changes
Product Manufacturing Information (PMI)
3D geometric dimensions and tolerances (GD&T)
Annotations (notes) and Model attributes
ITI & LOTAR - Validation of 3D GD&T “Presentation as Polyline”
Verify and Validate the 3D GD&T data in a STEP file
Check syntax and conformance with the express schema
Count the number of 3D GD&T entities in the STEP file
Total 3D GD&T data per view, per category (type) and for the part
Validate that the numbers of 3D GD&T are consistent with the new geometric validation properties (GVP) for 3D GD&T in the STEP file
55. Slide 55 Essentials for Effective STEP Interoperability Verification
Upstream model verification is essential to fix problems before they fester
Justify best practices and eliminate worst practices
Ensure suitability of models for downstream processes
Validation
Precise validation of STEP files is essential to guarantee accurate and true representations during CAD model export and import
Value of legacy data for design reuse
Quality of design data for downstream reuse
Integrity of design data for long term archive and retrieval
Process Automation
Robust and repeatable automatic process is required for efficient STEP interoperability
Minimize unknown risk
“What we do not know is most important”