2. Copyright (c) by Rajarathinam A. & Gadh R, 2000 Geometric Modeling in Multi-modal Multi-sensory Virtual Environment Arangarasan Rajarathinam arangara@cs.wisc.edu http://www.cs.wisc.edu/~arangara/ Ph.D. Student, UW-Madison Other Team Members Dr. Tushar H. Dani Mr. Chi Cheng Chu Mr. Xiaochun Liu Prof. Rajit Gadh Director, I-CARVE Lab Professor in ME Department University of Wisconsin-Madison

3. Copyright (c) by Rajarathinam A. & Gadh R, 2000 Introduction Conventional CAD systems and limitations How VR enables to overcome these limitations? COnceptual VIRtual Design System (COVIRDS) Detailed Virtual Design System (DVDS) Intelligent Assembly Feature (Smart-Mates) Hardware setup (Virtual Design Studio - VDS) Summary & Future research

4. Copyright (c) by Rajarathinam A. & Gadh R, 2000 Conventional CAD Systems Not suitable for concept shape modeling Bottleneck in I/O Interface Mapping Process in I/O Interface Single User System Collaboration becomes difficult Human sensories used: Hand, fingers, and eyes. 1D-Space 2D-Space 3D-Space 1D  2D 2D  3D 2D  3D Keyboard Fingers I/O DevicesMapping Modeling space Monitor Eyes Mouse Hand, Fingers Human sensories used: Hand, fingers, and eyes. 1D-Space 2D-Space 3D-Space 1D  2D 2D  3D 2D  3D Keyboard Fingers I/O DevicesMapping Modeling space Monitor Eyes Mouse Hand, Fingers

5. Copyright (c) by Rajarathinam A. & Gadh R, 2000 Motivation Develop concept & detailed virtual design system –High through-put of I/O interface –Intuitive & rapid modeling process –Visualization & manipulation of complex models –Collaborative design by multiple designers

6. Copyright (c) by Rajarathinam A. & Gadh R, 2000 Multi-modal, multi-sensory VR interface Voice Stereoscopic Display Mouth (Speech) Hands, head, body (3D Position Tracking) Eyes (Visual) 3D – Motion Gesture Fingers (Haptic) Force Feedback Skin (Tactile) Synthesised 3D-Sound Ears (Auditory) I/O Devices Modeling space 1D-space 2D-space 3D-space Human Sensories used: Mouth, fingers, hands, head, body, eyes, skin and ears. Eliminates mapping process. Direct manipulation of models.

7. Copyright (c) by Rajarathinam A. & Gadh R, 2000 Speech Interface Geometry Editing –Create –Delete –Modify/Dimension Geometry Manipulation –Selection –Location –Query Navigation –Zoom in/out –Viewpoint orientation

8. Copyright (c) by Rajarathinam A. & Gadh R, 2000 Hand Gestures and Actions PointingReleaseGrasp Translation Rotation RingOkay Resize Viewpoint Transformation

9. Copyright (c) by Rajarathinam A. & Gadh R, 2000 Additional Interaction Methods Input Interface –3D Menu –3D Toolbars –Sliders Output Interface –Synthesized voice –Text output

10. Copyright (c) by Rajarathinam A. & Gadh R, 2000 COVIRDS COnceptual VIRtual Design System Architecture Geometric modeler & representation Free-Form Surface Modeler Examples Limitations

11. Copyright (c) by Rajarathinam A. & Gadh R, 2000 COVIRDS - Architecture Designer ACIS Workspace Instances Speech Locator (WISL) Navigation Selection Manipulation Interaction Design Rules Snapping & Location Shape Elements & ‘Add’ Operation Modeling Design Editing Tools WTK Scene Graph (Device drivers, collision detection etc.) Design Intent Graph (D) Constraints, Grids, Design rules etc. Shape Modeling Graph (S) Rapid editing, Constraint enforcement, Rule evaluation Virtual Modeler Graphics/Geometry API User Interface Graphics/Geometry/CAD Solid Modeling Kernel User

12. Copyright (c) by Rajarathinam A. & Gadh R, 2000 Design Intent Graph, D –Captures designer’s intent –Depends on Sequence or operations Shape Modeling Graph, S –Geometric representation of part –Additional attributes to enable high- speed editing Intermediate Geometry Representation block b 1 rib r 4 boss o 2 boss o 3 b1b1 r4r4 o2o2 o3o3 D + + + b1b1 r4r4 o2o2 o3o3 S A A A

13. Copyright (c) by Rajarathinam A. & Gadh R, 2000 Parametric Surface Model

14. Copyright (c) by Rajarathinam A. & Gadh R, 2000 Assembly Models

15. Copyright (c) by Rajarathinam A. & Gadh R, 2000 Limitations Has its own geometric representation Data translation between CAD systems Not efficient for detailed shape modeling

16. Copyright (c) by Rajarathinam A. & Gadh R, 2000 DVDS Detailed Virtual Design System Architecture Functional difference between CAD Systems & DVDS Sketching “Liquid Features” Parametric Features Data Translation Examples

17. Copyright (c) by Rajarathinam A. & Gadh R, 2000 DVDS - Architecture DVDS CAD System - Data-base - (e.g.) DESIGNER(s) Command Parser Engine Voice Recognition Spatial Recognition Gesture Recognition Graphics Engine Stereoscopic Display Auditory Feedback Designer(s) Space Hardware Layer DVDS CAD Application

18. Copyright (c) by Rajarathinam A. & Gadh R, 2000 Sequence of Operations Bi-directional operations Uni-directional operations Geometric Space User Interaction Space Draw Sketches Add Feature Definition Add Feature Options Define Sketchplane Update PART Model Create Feature Conventional CAD Systems Add Feature Definition Update PART Model Define Sketches Add Feature Options Create Feature In DVDS Draw Sketches Add Feature Definition Add Feature Options Define Sketchplane Update Part Model Create Feature In Conventional CAD Systems

19. Copyright (c) by Rajarathinam A. & Gadh R, 2000 Sketching

20. Copyright (c) by Rajarathinam A. & Gadh R, 2000 “Liquid Features”

21. Copyright (c) by Rajarathinam A. & Gadh R, 2000 Sketched Features

22. Copyright (c) by Rajarathinam A. & Gadh R, 2000 Direct Features

23. Copyright (c) by Rajarathinam A. & Gadh R, 2000 Parametric Feature Definitions

24. Copyright (c) by Rajarathinam A. & Gadh R, 2000 Library Features

25. Copyright (c) by Rajarathinam A. & Gadh R, 2000 Data Translation - Editable - Full feature definition - Restores history Native Geometry (of CAD system) Imported Model Imported Model - Editable - No past features - No history - Non editable (Display only) - Triangulated Properties - Solidworks “PRT” TypesE.g. - Parasolid - SAT - VDAFS - STEP - IGES - VRML - STL - PROE Render

26. Copyright (c) by Rajarathinam A. & Gadh R, 2000 Example Models

27. Copyright (c) by Rajarathinam A. & Gadh R, 2000 Smart-Mates B-Rep models. Cost function. –E.G. Planar faces. Function of angle, projected area, shortest distance, area, etc. –E.G. Conic faces. Function of angle, radius, etc. Minimize cost function. Optimization for rapid computation. –At-least 60 fps in stereo mode.  R F1 F1’ F2 F2’ D 

28. Copyright (c) by Rajarathinam A. & Gadh R, 2000 Smart-Mates for B-Rep Models B-Rep models Features extraction FeatureN (higher order) Feature1 (e.g. Planar faces) Feature2 (e.g. conic faces) Cost Function1 Cost Function2Cost FunctionN Choose the best pair Pre-Computed Compute during the simulation

29. Copyright (c) by Rajarathinam A. & Gadh R, 2000 Potential Face Pairs Definition of cost function plays a vital role. Cost function varies based on the kind of geometries, applications, standards, rules, etc. For a selected face in one part, the potential face pairs in the other model is shown in the above figure. Model - AModel - B Selected Face Highlighted Faces

30. Copyright (c) by Rajarathinam A. & Gadh R, 2000 Different Face Pairs at Different Orientation

31. Copyright (c) by Rajarathinam A. & Gadh R, 2000 Feature Comparisons

32. Copyright (c) by Rajarathinam A. & Gadh R, 2000 Virtual Design Studio (VDS) For COVIRDS For DVDS

33. Copyright (c) by Rajarathinam A. & Gadh R, 2000 Collaborative Virtual Environment

34. Copyright (c) by Rajarathinam A. & Gadh R, 2000 Summary VR Technology for Geometric Modeling COVIRDS – Concept Shape Modeling System DVDS – Detailed Geometric Modeling System Smart-Mates – Feature for intelligent assembly Benefits Rapid & Intuitive Design Process Eliminates the need for expensive physical prototyping Reduces product cycle time and thus Cost effective Enables “human in the loop” analysis

35. Copyright (c) by Rajarathinam A. & Gadh R, 2000 Future Research Collaborative Virtual Environment VR2VR – Advanced Collaborative Visualization VR – Integration with human modeling software e.g. Jack, Safework

36. Copyright (c) by Rajarathinam A. & Gadh R, 2000 Acknowledgment Government –NSF, DOE, EPA, NASA (Federal) –UIR, Solid Waste Program, WARF (State) Industrial Partners –Ford, Pratt & Whitney, Caterpillar, Lucent, AT&T, Texas Instruments, FIAT, CMI New Alliances –General Dynamics, Boeing, Chrysler