2. Copyright (c) by Rajarathinam A. 2000 Geometric Modeling and Collaborative Design in a Multi-modal Multi-sensory Virtual Environment Rajarathinam Arangarasan Ph.D. Student, UW-Madison

3. Copyright (c) by Rajarathinam A. 2000 Introduction Conventional CAD systems and limitations How VR enables to overcome these limitations? Detailed Virtual Design System (DVDS) Intelligent Assembly Feature (Smart-Mates) Hardware setup (DVDS) Collaborative Virtual Environment (V2V) Summary & Future research

4. Copyright (c) by Rajarathinam A. 2000 Conventional CAD Systems Not suitable for concept shape modeling Bottleneck in I/O Interface Mapping Process in I/O Interface 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. 2000 Conventional CAD Systems Single User System Collaboration becomes difficult

6. Copyright (c) by Rajarathinam A. 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

7. Copyright (c) by Rajarathinam A. 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.

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

9. Copyright (c) by Rajarathinam A. 2000 Hand Gestures and Actions PointingReleaseGrasp Translation Rotation RingOkay Resize Viewpoint Transformation

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

11. Copyright (c) by Rajarathinam A. 2000 Parametric Surface Model

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

13. Copyright (c) by Rajarathinam A. 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

14. Copyright (c) by Rajarathinam A. 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 DVDS

15. Copyright (c) by Rajarathinam A. 2000 Sketch Entities Control Points Moving handle Rectangle Sketch Primitives Control points Description Two extreme points Circle Center and radius Circle 3 points on circumference Ellipse Center, point along major and minor axis resply. Arc Center, starting point and ending point on arc Arc Start, End and another point on arc Polyline End points of each line segment Spline Spline along the control points Centerline End points of line segment

16. Copyright (c) by Rajarathinam A. 2000 Sketching

17. Copyright (c) by Rajarathinam A. 2000 Liquid Features

18. Copyright (c) by Rajarathinam A. 2000 Direct Features

19. Copyright (c) by Rajarathinam A. 2000 Parametric Feature Definitions

20. Copyright (c) by Rajarathinam A. 2000 Library Features

21. Copyright (c) by Rajarathinam A. 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

22. Copyright (c) by Rajarathinam A. 2000 Example Models

23. Copyright (c) by Rajarathinam A. 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 

24. Copyright (c) by Rajarathinam A. 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

25. Copyright (c) by Rajarathinam A. 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

26. Copyright (c) by Rajarathinam A. 2000 Different Face Pairs at Different Orientation

27. Copyright (c) by Rajarathinam A. 2000 Feature Comparisons

28. Copyright (c) by Rajarathinam A. 2000 Detailed Virtual Design System For DVDS

29. Copyright (c) by Rajarathinam A. 2000 Designer in DVDS

30. Copyright (c) by Rajarathinam A. 2000 Multiple designers in a Virtual Environment

31. Copyright (c) by Rajarathinam A. 2000 Collaborative Virtual Environment (V2V) Architecture Data types and management Network topology and Session management Interface Modalities Clients Connectivity & Interface Modalities

32. Copyright (c) by Rajarathinam A. 2000 V2V - Architecture Server - 1 C-1C-2C-n Server - 2Server - n CODES Manager O1, O2 O3 O1

33. Copyright (c) by Rajarathinam A. 2000 Data types and Management Data Type Amount of data transmissionRequired network bandwidth Example application At session starting During simulation DDVaries from SS  HS > 100MbpsSimulation of CFD analysis PDVaries from SS  HS Varies from SS  MS 10Mbps ~ 100 Mbps Geometric modeling SD Varies from SS  HS SS24 Kbps ~ 10 Mbps Visualizing static objects ICVaries from SS  MS SS24 Kbps ~ 10 Mbps Interaction between clients DD - Highly Dynamic Data IC - Interface Communications PD - Partially Dynamic Data HS - Huge sized data sets SD - Static Data MS - Medium sized data sets IC - Interface Communications SS - Small sized data sets

34. Copyright (c) by Rajarathinam A. 2000 Server, Client and CODES manager Server Cache Objects Shared Methods Shared Objects CIM Table ASO Table Server side communication library Local cache of shared objects CIM table Client side communication library Client Applications library Interface modalities library CODES manager Client side communicatio n library Cached Objects CIM Table ASO Table Server side communicatio n library

35. Copyright (c) by Rajarathinam A. 2000 Interface Modalities Voice input Video Glove Data 3D Position / Orientation Convert to text + emotional info. Streamed Series of images of both the eyes Viewpoint Information Gesture ID 3D Tracking Perform the appropriate action Combine text and emotional info. Use both images for stereo display Render the scene for this viewpoint Visual display Play Display NETWORKNETWORK Sender’s perspective Receiver’s perspective

36. Copyright (c) by Rajarathinam A. 2000 Clients Connectivity and Interface Modalities (CIM) Table CS – Centralized data V – Voice inputS – Stereoscopic display RP – Replicated data G – GestureM – Monocular display T – 3D tracking A – Audio output Client System Type of Connection with server ReferencesAvailable I/O Interface Modalities Policy FromTo C1CSC2, C4C2, C3V, G, T, S, AA- C2CSC1 V, T, MM- C3RPC1 G, T, S, A C4CS C1V, G, T, S

37. Copyright (c) by Rajarathinam A. 2000 Summary VR Technology for Geometric Modeling DVDS – Detailed Geometric Modeling System Smart-Mates – Intelligent assembling V2V – Collaborative Virtual Environment Benefits Rapid & Intuitive Design Process Eliminates the need for expensive physical prototyping Reduces product cycle time and thus Cost effective

38. Copyright (c) by Rajarathinam A. 2000 Future Research V2V - Advanced Collaborative Visualization Integration with digital human modeling