DOCTORAATSPROEFSCHRIFT - EDM - UHasselt

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$Reflectance Model for Diffraction - EDM - UHasselt$

22 Defining Interactive Virtual Reality Applications problems with CS, such as the single point of failure, the network bottleneck and the extra delays. On the other hand, it introduces many other issues. All users need to maintain a list of other clients and need to handle users that join and leave the NVE. As a result the clients need to perform more operations and will also use much more network traffic. Furthermore, since clients need to handle all the consistency rules themselves it is much harder to implement and client software will be much more complex. Finally, in case of extra bandwidth requirements, it is much harder to upgrade for example all client’s networks. This, in contrast to the CS architecture where the server can be upgraded independently of the clients. P2P architectures appeared a few years earlier than CS systems. This probably resulted from the fact that using a dedicated server was very expensive in the beginning years of NVEs [Joslin 04]. Hybrid approaches employ techniques from both CS and P2P architectures, resolving the issues that come with the employment of one architecture. For example a single machine can be used to perform some specific management tasks but without it being used to distribute all the data as a server would do in the CS approach, resolving the network bottleneck. Another type of hybrid approach employs different architectures for different kinds of data. For example video can be streamed via a server while position updates among clients are sent in a P2P way. Many other kinds of hybrid approaches exist, however discussing all of them is beyond the scope of this work. On top of choosing the right architecture, NVE designers must also choose between different network protocols (TCP, UDP, multicast), choose reliability parameters (reliable UDP, unreliable multicast,. . . ) and can implement several improvements over dumb broadcasting of all updates to all users (dead reckoning techniques [Singhal 95], area of interest management policies [Boulanger 06], compression techniques,. . . ). Since the focus of this work is on the interaction within VEs and NVEs, we will not elaborate further on the subject of network architectures and efficient data distribution. More details on this subject can be found in [Macedonia 97, Quax 07]. 1.4.2 Distributing Simulation Similarly as on the network level, at the simulation level, NVE designers need to make choices on which network entities are responsible for keeping the simulation consistent and resolve conflicting interactions. Computer Supported Cooperative Work (CSCW) locking based floor control techniques [Dommel 97] are out of the question, since in dynamic NVEs, we want to allow interaction
1.4 State Synchronization and Distributing Simulation 23 (a) (b) Figure 1.2: The two basic distribution architectures: (a) Client-Server and (b) Peer-to-peer.
Page 1: DOCTORAATSPROEFSCHRIFT 2008 | Schoo
Page 5 and 6: Acknowledgments A researcher’s wo
Page 7 and 8: Abstract The field of networked vir
Page 9 and 10: Contents Acknowledgments i Abstract
Page 11 and 12: CONTENTS vii 8.1.2 Inverse Kinemati
Page 13 and 14: AI Artificial Intelligent AOI Area
Page 15 and 16: List of Figures 1.1 The different s
Page 17 and 18: LIST OF FIGURES xiii 10.1 Illustrat
Page 19 and 20: General Introduction The idea of cr
Page 21 and 22: Problem Statement One way of explai
Page 23 and 24: Contributions The overall purpose o
Page 25 and 26: Although the field we are working i
Page 27 and 28: This dissertation comprises five pa
Page 29: Part I BACKGROUND
Page 32 and 33: 14 TABLE OF CONTENTS
Page 34 and 35: 16 Defining Interactive Virtual Rea
Page 46 and 47: 28 A Brief Historical Overview Figu
Page 48 and 49: 30 A Brief Historical Overview comm
Page 50 and 51: 32 A Brief Historical Overview Figu
Page 52 and 53: 34 A Brief Historical Overview 2.2
Page 54 and 55: 36 A Brief Historical Overview (a)
Page 57 and 58: Table of Contents 3 Introduction 41
Page 59 and 60: CHAPTER3 Introduction In the genera
Page 61 and 62: Another interesting point, in the c
Page 63 and 64: CHAPTER4 Related Work While modelin
Page 65 and 66: proach, interactive surfaces descri
Page 67 and 68: CHAPTER5 A Dynamic Interactive Obje
Page 69 and 70: 5.2 Interactive Objects and Dynamic
Page 75 and 76: 5.3 The Interaction Layer 57 Listin
Page 77 and 78: 5.3 The Interaction Layer 59 Task 3
Page 79 and 80: 5.3 The Interaction Layer 61 Figure
Page 81 and 82: 5.4 Network Distribution and Simula
Page 83 and 84: 5.5 Evaluation of the Interactive O
Page 89 and 90: CHAPTER6 Conclusions In this part,
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Part III CREATING MORE REALISTIC DY
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76 TABLE OF CONTENTS
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78 Introduction to recent advances
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80 Introduction
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82 Related Work Figure 8.1: A model
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84 Related Work Figure 8.3: Illustr
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86 Related Work Figure 8.4: Ragdoll
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88 Related Work
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90 The ExtReAM Library: Extensible
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102 A Physically Simulated Dynamic
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110 Conclusions application develop
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Table of Contents 12 Introduction 1
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CHAPTER12 Introduction In the first
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117 effector of the IK chain of an
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CHAPTER13 Related Work In order to
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121 the rendering of rather static
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123 temperature and galvanic skin r
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CHAPTER14 An Avatar Control Method
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14.2 A Direct Avatar Controller Exp
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14.3 Distributing Animation Informa
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14.4 Results 131 frame, resulting i
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14.4 Results 133 Figure 14.3: Resul
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CHAPTER15 A Physical Travel Method
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15.1 Creating A Haptic Controller b
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15.2 Enabling Physical Travel 139 W
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15.2 Enabling Physical Travel 141 t
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15.2 Enabling Physical Travel 143 r
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CHAPTER16 Evaluating the Effects of
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16.1 The Haptic Travel Experiment 1
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16.1 The Haptic Travel Experiment 1
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16.2 Experimental Results 151 (a) (
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16.2 Experimental Results 153 pare
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16.2 Experimental Results 155 Figur
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CHAPTER17 Conclusions In contrast t
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Part V CONCLUSIONS AND FUTURE RESEA
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162 General Conclusions concepts of
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164 Directions for Further Research
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APPENDIXA Publications [Quax 03] P.
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APPENDIXB Dutch Summary - Samenvatt
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APPENDIXC C.1 Interactive Door Obje
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C.1 Interactive Door Object 173 <
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C.2 Physical Interactive Door Objec
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REFERENCES [3ds Max 07] Autodesk 3d
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179 Almitos, 1995. [Cal3D 07] Cal3D
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181 [Granny3D 07] Granny3D. http: /
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183 [Magnusson 02] C. Magnusson, K.
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185 Interaction, vol. 7, no. 4, pag
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187 Constraints for Articulated Fig
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