Issue 3

Permanent URI for this collection

https://diglib7.eg.org/handle/10.2312/106
EG 2002 Conference Proceedings

BibTeX (Issue 3)
                
@article{
10.1111:1467-8659.t01-3-00577,

journal = {Computer Graphics Forum},
title = {{
Artificial Animals and Humans: From Physics to Intelligence}},

author = {
Terzopoulos, Demetri
},
year = {
2002},

publisher = {
Blackwell Publishers, Inc and the Eurographics Association},


ISSN = {1467-8659},

DOI = {
10.1111/1467-8659.t01-3-00577}

}
                
@article{
10.1111:1467-8659.t01-1-00586,

journal = {Computer Graphics Forum},
title = {{
Deferred, Self-Organizing BSP Trees}},

author = {
Ar, Sigal
 and 
Montag, Gil
 and 
Tal, Ayellet
},
year = {
2002},

publisher = {
Blackwell Publishers, Inc and the Eurographics Association},


ISSN = {1467-8659},

DOI = {
10.1111/1467-8659.t01-1-00586}

}
                
@article{
10.1111:1467-8659.t01-1-00587,

journal = {Computer Graphics Forum},
title = {{
Fast Continuous Collision Detection between Rigid Bodies}},

author = {
Redon, Stephane
 and 
Kheddar, Abderrahmane
 and 
Coquillart, Sabine
},
year = {
2002},

publisher = {
Blackwell Publishers, Inc and the Eurographics Association},


ISSN = {1467-8659},

DOI = {
10.1111/1467-8659.t01-1-00587}

}
                
@article{
10.1111:1467-8659.t01-1-00588,

journal = {Computer Graphics Forum},
title = {{
Virtual Visual Servoing: a framework for real-time augmented reality}},

author = {
Marchand, Eric
 and 
Chaumette, Francois
},
year = {
2002},

publisher = {
Blackwell Publishers, Inc and the Eurographics Association},


ISSN = {1467-8659},

DOI = {
10.1111/1467-8659.t01-1-00588}

}
                
@article{
10.1111:1467-8659.00589,

journal = {Computer Graphics Forum},
title = {{
A Solid Model Based Virtual Hairy Brush}},

author = {
Xu, Songhua
 and 
Tang, Min
 and 
Lau, Francis
 and 
Pan, Yunhe
},
year = {
2002},

publisher = {
Blackwell Publishers, Inc and the Eurographics Association},


ISSN = {1467-8659},

DOI = {
10.1111/1467-8659.00589}

}
                
@article{
10.1111:1467-8659.00590,

journal = {Computer Graphics Forum},
title = {{
Geometric Approximations Towards Free Specular Comic Shading}},

author = {
Winnemoller, Holger
 and 
Bangay, Shaun
},
year = {
2002},

publisher = {
Blackwell Publishers, Inc and the Eurographics Association},


ISSN = {1467-8659},

DOI = {
10.1111/1467-8659.00590}

}
                
@article{
10.1111:1467-8659.t01-1-00591,

journal = {Computer Graphics Forum},
title = {{
Transparency in Interactive Technical Illustrations}},

author = {
Diepstraten, J.
 and 
Weiskopf, D.
 and 
Ertl, T.
},
year = {
2002},

publisher = {
Blackwell Publishers, Inc and the Eurographics Association},


ISSN = {1467-8659},

DOI = {
10.1111/1467-8659.t01-1-00591}

}
                
@article{
10.1111:1467-8659.t01-1-00592,

journal = {Computer Graphics Forum},
title = {{
Real-time Animation of Dressed Virtual Humans}},

author = {
Cordier, Frederic
 and 
Magnenat-Thalmann, Nadia
},
year = {
2002},

publisher = {
Blackwell Publishers, Inc and the Eurographics Association},


ISSN = {1467-8659},

DOI = {
10.1111/1467-8659.t01-1-00592}

}
                
@article{
10.1111:1467-8659.00593,

journal = {Computer Graphics Forum},
title = {{
Local Physical Models for Interactive Character Animation}},

author = {
Oore, Sageev
 and 
Terzopoulos, Demetri
 and 
Hinton, Geoffrey
},
year = {
2002},

publisher = {
Blackwell Publishers, Inc and the Eurographics Association},


ISSN = {1467-8659},

DOI = {
10.1111/1467-8659.00593}

}
                
@article{
10.1111:1467-8659.t01-1-00578,

journal = {Computer Graphics Forum},
title = {{
Interactive Visualization with Programmable Graphics Hardware}},

author = {
Ertl, Thomas
},
year = {
2002},

publisher = {
Blackwell Publishers, Inc and the Eurographics Association},


ISSN = {1467-8659},

DOI = {
10.1111/1467-8659.t01-1-00578}

}
                
@article{
10.1111:1467-8659.t01-1-00595,

journal = {Computer Graphics Forum},
title = {{
Efficient Fitting and Rendering of Large Scattered Data Sets Using Subdivision Surfaces}},

author = {
Scheib, Vincent
 and 
Haber, Jorg
 and 
Lin, Ming C.
 and 
Seidel, Hans-Peter
},
year = {
2002},

publisher = {
Blackwell Publishers, Inc and the Eurographics Association},


ISSN = {1467-8659},

DOI = {
10.1111/1467-8659.t01-1-00595}

}
                
@article{
10.1111:1467-8659.00594,

journal = {Computer Graphics Forum},
title = {{
STRANDS: Interactive Simulation of Thin Solids using Cosserat Models}},

author = {
Pai, Dinesh K.
},
year = {
2002},

publisher = {
Blackwell Publishers, Inc and the Eurographics Association},


ISSN = {1467-8659},

DOI = {
10.1111/1467-8659.00594}

}
                
@article{
10.1111:1467-8659.t01-1-00599,

journal = {Computer Graphics Forum},
title = {{
Using Perceptual Texture Masking for Efficient Image Synthesis}},

author = {
Walter, Bruce
 and 
Pattanaik, Sumanta N.
 and 
Greenberg, Donald P.
},
year = {
2002},

publisher = {
Blackwell Publishers, Inc and the Eurographics Association},


ISSN = {1467-8659},

DOI = {
10.1111/1467-8659.t01-1-00599}

}
                
@article{
10.1111:1467-8659.00596,

journal = {Computer Graphics Forum},
title = {{
Surface reconstruction based on a dynamical system?}},

author = {
Giesen, Joachim
 and 
John, Matthias
},
year = {
2002},

publisher = {
Blackwell Publishers, Inc and the Eurographics Association},


ISSN = {1467-8659},

DOI = {
10.1111/1467-8659.00596}

}
                
@article{
10.1111:1467-8659.t01-1-00598,

journal = {Computer Graphics Forum},
title = {{
Angle-Analyzer: A Triangle-Quad Mesh Codec}},

author = {
Lee, Haeyoung
 and 
Alliez, Pierre
 and 
Desbrun, Mathieu
},
year = {
2002},

publisher = {
Blackwell Publishers, Inc and the Eurographics Association},


ISSN = {1467-8659},

DOI = {
10.1111/1467-8659.t01-1-00598}

}
                
@article{
10.1111:1467-8659.t01-1-00597,

journal = {Computer Graphics Forum},
title = {{
A Frequency-Domain Approach to Watermarking 3D Shapes}},

author = {
Ohbuchi, 1 Ryutarou
 and 
Mukaiyama, 1 Akio
 and 
Takahashi, 2 Shigeo
},
year = {
2002},

publisher = {
Blackwell Publishers, Inc and the Eurographics Association},


ISSN = {1467-8659},

DOI = {
10.1111/1467-8659.t01-1-00597}

}
                
@article{
10.1111:1467-8659.00602,

journal = {Computer Graphics Forum},
title = {{
Projective Texture Mapping with Full Panorama}},

author = {
Kim, Dongho
 and 
Hahn, James K.
},
year = {
2002},

publisher = {
Blackwell Publishers, Inc and the Eurographics Association},


ISSN = {1467-8659},

DOI = {
10.1111/1467-8659.00602}

}
                
@article{
10.1111:1467-8659.t01-1-00600,

journal = {Computer Graphics Forum},
title = {{
Texture Particles}},

author = {
Dischler, J.-M.
 and 
Maritaud, K.
 and 
Levy, B.
 and 
Ghazanfarpour, D.
},
year = {
2002},

publisher = {
Blackwell Publishers, Inc and the Eurographics Association},


ISSN = {1467-8659},

DOI = {
10.1111/1467-8659.t01-1-00600}

}
                
@article{
10.1111:1467-8659.t01-1-00601,

journal = {Computer Graphics Forum},
title = {{
Space-Optimized Texture Maps}},

author = {
Balmelli, Laurent
 and 
Taubin, Gabriel
 and 
Bernardini, Fausto
},
year = {
2002},

publisher = {
Blackwell Publishers, Inc and the Eurographics Association},


ISSN = {1467-8659},

DOI = {
10.1111/1467-8659.t01-1-00601}

}
                
@article{
10.1111:1467-8659.00603,

journal = {Computer Graphics Forum},
title = {{
Sculpturing on Discrete Displacement Fields}},

author = {
Ayasse, Jorg
 and 
Muller, Heinrich
},
year = {
2002},

publisher = {
Blackwell Publishers, Inc and the Eurographics Association},


ISSN = {1467-8659},

DOI = {
10.1111/1467-8659.00603}

}
                
@article{
10.1111:1467-8659.00579,

journal = {Computer Graphics Forum},
title = {{
3D Scanning Technology: Capabilities and Issues}},

author = {
Scopigno, Roberto
},
year = {
2002},

publisher = {
Blackwell Publishers, Inc and the Eurographics Association},


ISSN = {1467-8659},

DOI = {
10.1111/1467-8659.00579}

}
                
@article{
10.1111:1467-8659.t01-1-00605,

journal = {Computer Graphics Forum},
title = {{
Slow Growing Subdivision (SGS) in Any Dimension: Towards Removing the Curse of Dimensionality}},

author = {
Pascucci, V.
},
year = {
2002},

publisher = {
Blackwell Publishers, Inc and the Eurographics Association},


ISSN = {1467-8659},

DOI = {
10.1111/1467-8659.t01-1-00605}

}
                
@article{
10.1111:1467-8659.t01-1-00604,

journal = {Computer Graphics Forum},
title = {{
Image-Swept Volumes}},

author = {
Winter, Andrew S.
 and 
Chen, Min
},
year = {
2002},

publisher = {
Blackwell Publishers, Inc and the Eurographics Association},


ISSN = {1467-8659},

DOI = {
10.1111/1467-8659.t01-1-00604}

}
                
@article{
10.1111:1467-8659.00606,

journal = {Computer Graphics Forum},
title = {{
Object Space EWA Surface Splatting: A Hardware Accelerated Approach to High Quality Point Rendering}},

author = {
Ren, Liu
 and 
Pfister, Hanspeter
 and 
Zwicker, Matthias
},
year = {
2002},

publisher = {
Blackwell Publishers, Inc and the Eurographics Association},


ISSN = {1467-8659},

DOI = {
10.1111/1467-8659.00606}

}
                
@article{
10.1111:1467-8659.00607,

journal = {Computer Graphics Forum},
title = {{
Hybrid Geometric - Image Based Rendering}},

author = {
Hidalgo, Eduardo
 and 
Hubbold, Roger J.
},
year = {
2002},

publisher = {
Blackwell Publishers, Inc and the Eurographics Association},


ISSN = {1467-8659},

DOI = {
10.1111/1467-8659.00607}

}
                
@article{
10.1111:1467-8659.t01-1-00608,

journal = {Computer Graphics Forum},
title = {{
Multi-Resolution Rendering of Complex Animated Scenes}},

author = {
Wand, M.
 and 
Strasser, W.
},
year = {
2002},

publisher = {
Blackwell Publishers, Inc and the Eurographics Association},


ISSN = {1467-8659},

DOI = {
10.1111/1467-8659.t01-1-00608}

}
                
@article{
10.1111:1467-8659.00701,

journal = {Computer Graphics Forum},
title = {{
Automatic Integration of Facade Textures into 3D Building Models with a Projective Geometry Based Line Clustering}},

author = {
Lee, Sung Chun
 and 
Jung, Soon Ki
 and 
Nevatia, Ram
},
year = {
2002},

publisher = {
Blackwell Publishers, Inc and the Eurographics Association},


ISSN = {1467-8659},

DOI = {
10.1111/1467-8659.00701}

}
                
@article{
10.1111:1467-8659.t01-1-00700,

journal = {Computer Graphics Forum},
title = {{
Representation of Pseudo Inter-reflection and Transparency by Considering Characteristics of Human Vision}},

author = {
Matsuoka, H.
 and 
Takeuchi, T.
 and 
Kitazawa, H.
 and 
Onozawa, A.
},
year = {
2002},

publisher = {
Blackwell Publishers, Inc and the Eurographics Association},


ISSN = {1467-8659},

DOI = {
10.1111/1467-8659.t01-1-00700}

}
                
@article{
10.1111:1467-8659.t01-1-00609,

journal = {Computer Graphics Forum},
title = {{
Dynamic Textures for Image-based Rendering of Fine-Scale 3D Structure and Animation of Non-rigid Motion}},

author = {
Cobzas, Dana
 and 
Yerex, Keith
 and 
Jagersand, Martin
},
year = {
2002},

publisher = {
Blackwell Publishers, Inc and the Eurographics Association},


ISSN = {1467-8659},

DOI = {
10.1111/1467-8659.t01-1-00609}

}
                
@article{
10.1111:1467-8659.t01-1-00703,

journal = {Computer Graphics Forum},
title = {{
A Simple and Robust Mutation Strategy for the Metropolis Light Transport Algorithm}},

author = {
Kelemen, Csaba
 and 
Szirmay-Kalos, Laszlo
 and 
Antal, Gyorgy
 and 
Csonka, Ferenc
},
year = {
2002},

publisher = {
Blackwell Publishers, Inc and the Eurographics Association},


ISSN = {1467-8659},

DOI = {
10.1111/1467-8659.t01-1-00703}

}
                
@article{
10.1111:1467-8659.00702,

journal = {Computer Graphics Forum},
title = {{
Improved Scene Reconstruction from Range Images}},

author = {
Wang, Jianning
 and 
Oliveira, Manuel M.
},
year = {
2002},

publisher = {
Blackwell Publishers, Inc and the Eurographics Association},


ISSN = {1467-8659},

DOI = {
10.1111/1467-8659.00702}

}
                
@article{
10.1111:1467-8659.t01-1-00705,

journal = {Computer Graphics Forum},
title = {{
Grid Based Final Gather for Radiosity on Complex Clustered Scenes}},

author = {
Scheel, Annette
 and 
Stamminger, Marc
 and 
Seidel, Hans-Peter
},
year = {
2002},

publisher = {
Blackwell Publishers, Inc and the Eurographics Association},


ISSN = {1467-8659},

DOI = {
10.1111/1467-8659.t01-1-00705}

}
                
@article{
10.1111:1467-8659.00704,

journal = {Computer Graphics Forum},
title = {{
Advanced Radiance Estimation For Photon Map Global Illumination}},

author = {
Hey, Heinrich
 and 
Purgathofer, Werner
},
year = {
2002},

publisher = {
Blackwell Publishers, Inc and the Eurographics Association},


ISSN = {1467-8659},

DOI = {
10.1111/1467-8659.00704}

}
                
@article{
10.1111:1467-8659.00580,

journal = {Computer Graphics Forum},
title = {{
Intrinsic Parameterizations of Surface Meshes}},

author = {
Desbrun, Mathieu
 and 
Meyer, Mark
 and 
Alliez, Pierre
},
year = {
2002},

publisher = {
Blackwell Publishers, Inc and the Eurographics Association},


ISSN = {1467-8659},

DOI = {
10.1111/1467-8659.00580}

}
                
@article{
10.1111:1467-8659.00706,

journal = {Computer Graphics Forum},
title = {{
Efficient Multidimensional Sampling}},

author = {
Kollig, Thomas
 and 
Keller, Alexander
},
year = {
2002},

publisher = {
Blackwell Publishers, Inc and the Eurographics Association},


ISSN = {1467-8659},

DOI = {
10.1111/1467-8659.00706}

}
                
@article{
10.1111:1467-8659.t01-1-00709,

journal = {Computer Graphics Forum},
title = {{
Free-form sketching with variational implicit surfaces}},

author = {
Karpenko, Olga
 and 
Hughes, John F.
 and 
Raskar, Ramesh
},
year = {
2002},

publisher = {
Blackwell Publishers, Inc and the Eurographics Association},


ISSN = {1467-8659},

DOI = {
10.1111/1467-8659.t01-1-00709}

}
                
@article{
10.1111:1467-8659.t01-1-00708,

journal = {Computer Graphics Forum},
title = {{
Hardware-Based Volumetric Knit-Wear}},

author = {
Daubert, Katja
 and 
Seidel, Hans-Peter
},
year = {
2002},

publisher = {
Blackwell Publishers, Inc and the Eurographics Association},


ISSN = {1467-8659},

DOI = {
10.1111/1467-8659.t01-1-00708}

}
                
@article{
10.1111:1467-8659.t01-1-00707,

journal = {Computer Graphics Forum},
title = {{
A Biologically-Parameterized Feather Model}},

author = {
Streit, L.
 and 
Heidrich, W.
},
year = {
2002},

publisher = {
Blackwell Publishers, Inc and the Eurographics Association},


ISSN = {1467-8659},

DOI = {
10.1111/1467-8659.t01-1-00707}

}
                
@article{
10.1111:1467-8659.t01-1-00710,

journal = {Computer Graphics Forum},
title = {{
Designing 2D Vector Fields of Arbitrary Topology}},

author = {
Theisel, H.
},
year = {
2002},

publisher = {
Blackwell Publishers, Inc and the Eurographics Association},


ISSN = {1467-8659},

DOI = {
10.1111/1467-8659.t01-1-00710}

}
                
@article{
10.1111:j.1467-8659.2002.00712.x,

journal = {Computer Graphics Forum},
title = {{
Color Section}},

author = {},
year = {
2002},

publisher = {
Blackwell Publishers Ltd and the Eurographics Association.},


ISSN = {1467-8659},

DOI = {
10.1111/j.1467-8659.2002.00712.x}

}
                
@article{
10.1111:1467-8659.t01-1-00711,

journal = {Computer Graphics Forum},
title = {{
Hardware Accelerated Interactive Vector Field Visualization: A level of detail approach}},

author = {
Bordoloi, Udeepta
 and 
Shen, Han-Wei
},
year = {
2002},

publisher = {
Blackwell Publishers, Inc and the Eurographics Association},


ISSN = {1467-8659},

DOI = {
10.1111/1467-8659.t01-1-00711}

}
                
@article{
10.1111:1467-8659.t01-1-00582,

journal = {Computer Graphics Forum},
title = {{
Geometric Snakes for Triangular Meshes}},

author = {
Lee, Y.
 and 
Lee, S.
},
year = {
2002},

publisher = {
Blackwell Publishers, Inc and the Eurographics Association},


ISSN = {1467-8659},

DOI = {
10.1111/1467-8659.t01-1-00582}

}
                
@article{
10.1111:1467-8659.00581,

journal = {Computer Graphics Forum},
title = {{
Metamorphosis of Polyhedral Surfaces using Decomposition}},

author = {
Shlafman, Shymon
 and 
Tal, Ayellet
 and 
Katz, Sagi
},
year = {
2002},

publisher = {
Blackwell Publishers, Inc and the Eurographics Association},


ISSN = {1467-8659},

DOI = {
10.1111/1467-8659.00581}

}
                
@article{
10.1111:1467-8659.00583,

journal = {Computer Graphics Forum},
title = {{
Flattening 3D objects using silhouettes}},

author = {
Martin, D.
 and 
Fekete, J.D.
 and 
Torres, J. C.
},
year = {
2002},

publisher = {
Blackwell Publishers, Inc and the Eurographics Association},


ISSN = {1467-8659},

DOI = {
10.1111/1467-8659.00583}

}
                
@article{
10.1111:1467-8659.00584,

journal = {Computer Graphics Forum},
title = {{
Stylizing Silhouettes at Interactive Rates: From Silhouette Edges to Silhouette Strokes}},

author = {
Isenberg, Tobias
 and 
Halper, Nick
 and 
Strothotte, Thomas
},
year = {
2002},

publisher = {
Blackwell Publishers, Inc and the Eurographics Association},


ISSN = {1467-8659},

DOI = {
10.1111/1467-8659.00584}

}
                
@article{
10.1111:1467-8659.t01-1-00585,

journal = {Computer Graphics Forum},
title = {{
Modeling Surperspective Projection of Landscapes for Geographical Guide-Map Generation}},

author = {
Takahashi, Shigeo
 and 
Ohta, Naoya
 and 
Nakamura, Hiroko
 and 
Takeshima, Yuriko
 and 
Fujishiro, Issei
},
year = {
2002},

publisher = {
Blackwell Science Ltd and the Eurographics Association},


ISSN = {1467-8659},

DOI = {
10.1111/1467-8659.t01-1-00585}

}

Browse

Recent Submissions

Now showing 1 - 46 of 46
  • No Thumbnail Available
    Item
    Artificial Animals and Humans: From Physics to Intelligence
    (Blackwell Publishers, Inc and the Eurographics Association, 2002) Terzopoulos, Demetri
    The confluence of virtual reality and artificial life, an emerging discipline that spans the computational and biological sciences, has yielded synthetic worlds inhabited by realistic, artificial flora and fauna. Artificial animals are complex synthetic organisms that possess functional biomechanical bodies, sensors, and brains with locomotion, perception, behavior, learning, and cognition centers. Artificial humans and other animals are of interest in computer graphics because they are self-animating characters that dramatically advance the state of the art of production animation and interactive game technologies. More broadly, these biomimetic autonomous agents in their realistic virtual worlds also foster deeper, computationally oriented insights into natural living systems.
  • No Thumbnail Available
    Item
    Deferred, Self-Organizing BSP Trees
    (Blackwell Publishers, Inc and the Eurographics Association, 2002) Ar, Sigal; Montag, Gil; Tal, Ayellet
    bsptrees and KD trees are fundamental data structures for collision detection in walkthrough environments. A basic issue in the construction of these hierarchical data structures is the choice of cutting planes. Rather than base these choices solely on the properties of the scene, we propose using information about how the tree is used in order to determine its structure. We demonstrate how this leads to the creation ofbsptrees that are small, do not require much preprocessing time, and respond very efficiently to sequences of collision queries.Categories and Subject Descriptors (according to ACM CCS): I.3.5 [Computer Graphics]: Computational Geometry and Object Modeling I.3.6 [Computer Graphics]: Graphics data structures and data types, Interaction techniques I.3.7 [Computer Graphics]: Virtual reality
  • No Thumbnail Available
    Item
    Fast Continuous Collision Detection between Rigid Bodies
    (Blackwell Publishers, Inc and the Eurographics Association, 2002) Redon, Stephane; Kheddar, Abderrahmane; Coquillart, Sabine
    This paper introduces a fast continuous collision detection technique for polyhedral rigid bodies. As opposed to most collision detection techniques, the computation of the first contact time between two objects is inherently part of the algorithm. The method can thus robustly prevent objects interpenetrations or collisions misses, even when objects are thin or have large velocities. The method is valid for general objects (polygon soups), handles multiple moving objects and acyclic articulated bodies, and is efficient in low and high coherency situations. Moreover, the method can be used to speed up existent continuous collision detection methods for parametric or implicit rigid surfaces. The collision detection algorithms have been successfully coupled to a real-time dynamics simulator. Various experiments are conducted that show the method's ability to produce high-quality interaction (precise objects positioning for example) between models up to tens of thousands of triangles, which couldn't have been performed with previous continuous methods.Categories and Subject Descriptors (according to ACM CCS): I.3.7 [Computer Graphics]: Animation - Virtual Reality
  • No Thumbnail Available
    Item
    Virtual Visual Servoing: a framework for real-time augmented reality
    (Blackwell Publishers, Inc and the Eurographics Association, 2002) Marchand, Eric; Chaumette, Francois
    This paper presents a framework to achieve real-time augmented reality applications. We propose a framework based on the visual servoing approach well known in robotics. We consider pose or viewpoint computation as a similar problem to visual servoing. It allows one to take advantage of all the research that has been carried out in this domain in the past. The proposed method features simplicity, accuracy, efficiency, and scalability wrt. to the camera model as well as wrt. the features extracted from the image. We illustrate the efficiency of our approach on augmented reality applications with various real image sequences.
  • No Thumbnail Available
    Item
    A Solid Model Based Virtual Hairy Brush
    (Blackwell Publishers, Inc and the Eurographics Association, 2002) Xu, Songhua; Tang, Min; Lau, Francis; Pan, Yunhe
    We present the detailed modeling of the hairy brush used typically in Chinese calligraphy. The complex model, which includes also a model for the ink and the paper, covers the various stages of the brush going through a calligraphy process. The model relies on the concept of writing primitives, which are the smallest units of hair clusters, to reduce the load on the simulation. Each such primitive is constructed through the general sweeping operation in CAD and described by a NURBS surface. The writing primitives dynamically adjust themselves during the virtual writing process, leaving an imprint on the virtual paper as they move. The behavior of the brush is an aggregation of the behavior of all the writing primitives. A software system based on the model has been built and tested. Samples of imitation artwork from using the system were obtained and found to be nearly indistinguishable from the real artwork.Categories and Subject Descriptors (according to ACM CCS): I.3.6 [Methodology and Techniques]: Interaction techniques I.3.5 [Computational Geometry and Object Modeling]: Physically based modeling I.3.4 [Graphics Utilities]: Paint systems
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    Geometric Approximations Towards Free Specular Comic Shading
    (Blackwell Publishers, Inc and the Eurographics Association, 2002) Winnemoller, Holger; Bangay, Shaun
    We extend the standard solution to comic rendering with a comic-style specular component. To minimise the computational overhead associated with this extension, we introduce two optimising approximations; the perspective correction angle and the vertex face-orientation measure. Both of these optimisations are generally applicable, but they are especially well suited for applications where a physically correct lighting simulation is not required. Using our optimisations we achieve performances comparable to the standard solution. As our approximations favour large models, we even outperform the standard approach for models consisting of 10,000 triangles or more, which we can render exceeding 40 frames per second, including the specular component.Categories and Subject Descriptors (according to ACM CSS): I.3.3 [Computer Graphics] Picture/Image Generation: Display algorithms; I.3.7 [Computer Graphics] Three-Dimensional Graphics and Realism: Color, shading, shadowing, and texture; I.4.3 [Image Processing and Computer Vision] Enhancements: Geometric Correction.
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    Transparency in Interactive Technical Illustrations
    (Blackwell Publishers, Inc and the Eurographics Association, 2002) Diepstraten, J.; Weiskopf, D.; Ertl, T.
    This paper describes how technical illustrations containing opaque and non-opaque objects can be automatically generated. Traditional methods to show transparency in manual drawings are evaluated to extract a small and effective set of rules for computer-based rendering of technical illustrations, leading to a novel view-dependent transparency model. We propose a hardware-accelerated depth sorting algorithm in image-space which specifically meets the requirements of our transparency model. In this way, real-time rendering of semi-transparent technical illustrations is achieved. Finally, it is described how our approach can be combined with other methods in the field of non-photorealistic rendering in order to enhance the visual perception of technical illustrations.Categories and Subject Descriptors (according to ACM CCS): I.3.7 [Computer Graphics]: Color, shading, shadowing and texture
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    Real-time Animation of Dressed Virtual Humans
    (Blackwell Publishers, Inc and the Eurographics Association, 2002) Cordier, Frederic; Magnenat-Thalmann, Nadia
    In this paper, we describe a method for cloth animation in real-time. The algorithm works in a hybrid manner exploiting the merits of both the physical-based and geometric deformations. It makes use of predetermined conditions between the cloth and the body model, avoiding complex collision detection and physical deformations wherever possible. Garments are segmented into pieces that are simulated by various algorithms, depending on how they are laid on the body surface and whether they stick or flow on it. Tests show that the method is well suited to fully dressed virtual human models, achieving real-time performance compared to ordinary cloth-simulations.
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    Local Physical Models for Interactive Character Animation
    (Blackwell Publishers, Inc and the Eurographics Association, 2002) Oore, Sageev; Terzopoulos, Demetri; Hinton, Geoffrey
    Our goal is to design and build a tool for the creation of expressive character animation. Virtual puppetry, also known as performance animation, is a technique in which the user interactively controls a character's motion. In this paper we introduce local physical models for performance animation and describe how they can augment an existing kinematic method to achieve very effective animation control. These models approximate specific physically-generated aspects of a character's motion. They automate certain behaviours, while still letting the user override such motion via a PD-controller if he so desires. Furthermore, they can be tuned to ignore certain undesirable effects, such as the risk of having a character fall over, by ignoring corresponding components of the force. Although local physical models are a quite simple approximation to real physical behaviour, we show that they are extremely useful for interactive character control, and contribute positively to the expressiveness of the character's motion. In this paper, we develop such models at the knees and ankles of an interactively-animated 3D anthropomorphic character, and demonstrate a resulting animation. This approach can be applied in a straight-forward way to other joints.Categories and Subject Descriptors (according to ACM CCS): I.3.7 [Computer Graphics]: Three-Dimensional Graphics and Realism, Interaction Techniques
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    Interactive Visualization with Programmable Graphics Hardware
    (Blackwell Publishers, Inc and the Eurographics Association, 2002) Ertl, Thomas
    One of the main scientific goals of visualization is the development of algorithms and appropriate data models which facilitate interactive visual analysis and direct manipulation of the increasingly large data sets which result from simulations running on massive parallel computer systems, from measurements employing fast high-resolution sensors, or from large databases and hierarchical information spaces.This task can only be achieved with the optimization of all stages of the visualization pipeline: filtering, compression, and feature extraction of the raw data sets, adaptive visualization mappings which allow the users to choose between speed and accuracy, and exploiting new graphics hardware features for fast and high-quality rendering. The recent introduction of advanced programmability in widely available graphics hardware has already led to impressive progress in the area of volume visualization. However, besides the acceleration of the final rendering, flexible graphics hardware is increasingly being used also for the mapping and filtering stages of the visualization pipeline, thus giving rise to new levels of interactivity in visualization applications. The talk will present recent results of applying programmable graphics hardware in various visualization algorithms covering volume data, flow data, terrains, NPR rendering, and distributed and remote applications.
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    Efficient Fitting and Rendering of Large Scattered Data Sets Using Subdivision Surfaces
    (Blackwell Publishers, Inc and the Eurographics Association, 2002) Scheib, Vincent; Haber, Jorg; Lin, Ming C.; Seidel, Hans-Peter
    We present a method to efficiently construct and render a smooth surface for approximation of large functional scattered data. Using a subdivision surface framework and techniques from terrain rendering, the resulting surface can be explored from any viewpoint while maintaining high surface fairness and interactive frame rates. We show the approximation error to be sufficiently small for several large data sets. Our system allows for adaptive simplification and provides continuous levels of detail, taking into account the local variation and distribution of the data.Categories and Subject Descriptors (according to ACM CCS): G.1.2 [Approximation]: Approximation of surfaces, Least squares approximation, Piecewise polynomial approximation; I.3.3 [Picture/Image Generation]: Display algorithms, Viewing algorithms; I.3.5 [Computational Geometry and Object Modeling]: Surface representation.
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    STRANDS: Interactive Simulation of Thin Solids using Cosserat Models
    (Blackwell Publishers, Inc and the Eurographics Association, 2002) Pai, Dinesh K.
    Strandsare thin elastic solids that are visually well approximated as smooth curves, and yet possess essential physical behaviors characteristic of solid objects such as twisting. Common examples in computer graphics include: sutures, catheters, and tendons in surgical simulation; hairs, ropes, and vegetation in animation. Physical models based on spring meshes or 3D finite elements for such thin solids are either inaccurate or inefficient for interactive simulation. In this paper we show that models based on the Cosserat theory of elastic rods are very well suited for interactive simulation of these objects. The physical model reduces to a system of spatial ordinary differential equations that can be solved efficiently for typical boundary conditions. The model handles the important geometric non-linearity due to large changes in shape. We introduce Cosserat-type physical models, describe efficient numerical methods for interactive simulation of these models, and implementation results.
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    Using Perceptual Texture Masking for Efficient Image Synthesis
    (Blackwell Publishers, Inc and the Eurographics Association, 2002) Walter, Bruce; Pattanaik, Sumanta N.; Greenberg, Donald P.
    Texture mapping has become indispensable in image synthesis as an inexpensive source of rich visual detail. Less obvious, but just as useful, is its ability to mask image errors due to inaccuracies in geometry or lighting. This ability can be used to substantially accelerate rendering by eliminating computations when the resulting errors will be perceptually insignificant.Our new method precomputes the masking ability of textures using aspects of the JPEG image compression standard. This extra information is stored as threshold elevation factors in the texture's mip-map and interpolated at image generation time as part of the normal texture lookup process. Any algorithm which uses error tolerances or visibility thresholds can then take advantage of texture masking. Applications to adaptive shadow testing, irradiance caching, and path tracing are demonstrated.Unlike prior methods, our approach does not require that initial images be computed before masking can be exploited and incurs only negligible runtime computational overhead. Thus, it is much easier to integrate with existing rendering systems for both static and dynamic scenes and yields computational savings even when only small amounts of texture masking are present.Categories and Subject Descriptors (according to ACM CCS): I.3.7 [Computer Graphics]: Color, shading, shadowing, and texture
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    Surface reconstruction based on a dynamical system?
    (Blackwell Publishers, Inc and the Eurographics Association, 2002) Giesen, Joachim; John, Matthias
    We present an efficient algorithm that computes a manifold triangular mesh from a set of unorganized sample points in. The algorithm builds on the observation made by several researchers that the Gabriel graph of the sample points provides a good surface description. However, this surface description is only one-dimensional. We associate the edges of the Gabriel graph with index 1 critical points of a dynamical system induced by the sample points. Exploiting also the information contained in the critical points of index 2 provides a two-dimensional surface description which can be easily turned into a manifold.
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    Angle-Analyzer: A Triangle-Quad Mesh Codec
    (Blackwell Publishers, Inc and the Eurographics Association, 2002) Lee, Haeyoung; Alliez, Pierre; Desbrun, Mathieu
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    A Frequency-Domain Approach to Watermarking 3D Shapes
    (Blackwell Publishers, Inc and the Eurographics Association, 2002) Ohbuchi, 1 Ryutarou; Mukaiyama, 1 Akio; Takahashi, 2 Shigeo
    This paper presents a robust watermarking algorithm with informed detection for 3D polygonal meshes. The algorithm is based on our previous algorithm [22] that employs mesh-spectral analysis to modify mesh shapes in their transformed domain. This paper presents extensions to our previous algorithm so that (1) much larger meshes can be watermarked within a reasonable time, and that (2) the watermark is robust against connectivity alteration (e.g., mesh simplification), and that (3) the watermark is robust against attacks that combine similarity transformation with such other attacks as cropping, mesh simplification, and smoothing. Experiment showed that our new watermarks are resistant against mesh simplification and remeshing combined with resection, similarity transformation, and other operations..
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    Projective Texture Mapping with Full Panorama
    (Blackwell Publishers, Inc and the Eurographics Association, 2002) Kim, Dongho; Hahn, James K.
    Projective texture mapping is used to project a texture map onto scene geometry. It has been used in many applications, since it eliminates the assignment of fixed texture coordinates and provides a good method of representing synthetic images or photographs in image-based rendering. But conventional projective texture mapping has limitations in the field of view and the degree of navigation because only simple rectangular texture maps can be used.In this work, we propose the concept of panoramic projective texture mapping (PPTM). It projects cubic or cylindrical panorama onto the scene geometry. With this scheme, any polygonal geometry can receive the projection of a panoramic texture map, without using fixed texture coordinates or modeling many projective texture mapping. For fast real-time rendering, a hardware-based rendering method is also presented. Applications of PPTM include panorama viewer similar to QuicktimeVR and navigation in the panoramic scene, which can be created by image-based modeling techniques.Categories and Subject Descriptors (according to ACM CCS): I.3.3 [Computer Graphics]: Viewing Algorithms; I.3.7 [Computer Graphics]: Color, Shading, Shadowing, and Texture
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    Texture Particles
    (Blackwell Publishers, Inc and the Eurographics Association, 2002) Dischler, J.-M.; Maritaud, K.; Levy, B.; Ghazanfarpour, D.
    This paper presents an analytical extension of texture synthesis techniques based on the distribution of elementary texture components. Our approach is similar to the bombing, cellular, macrostructured and lapped textures techniques, but provides the user with more control on both the texture analysis and synthesis phases. Therefore, high quality results can be obtained for a large number of structured or stochastic textures (bricks, marble, lawn, etc.). The analysis consists in decomposing textures into elementary components - that we call 'texture particles' - and for which we analyze their specific spatial arrangements. The synthesis then consists in recomposing similar textures directly on arbitrary surfaces by taking into account the previously computed arrangements, extended to 3D surfaces. Compared to 'pixel-based' analysis and synthesis methods, which have been recently generalized to arbitrary surfaces, our approach has three major advantages: (1) it is fast, which allows the user to interactively control the synthesis process. This further allows us to propose a large number of tools, granting a high degree of artistic freedom to the user. (2) It avoids the visual deterioration of the texture components by preserving their shapes as well as their spatial arrangements. (3) The texture particles can be not only images, but also 3D geometric elements, which extends significantly the domain of application.
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    Space-Optimized Texture Maps
    (Blackwell Publishers, Inc and the Eurographics Association, 2002) Balmelli, Laurent; Taubin, Gabriel; Bernardini, Fausto
    Texture mapping is a common operation to increase the realism of three-dimensional meshes at low cost. We propose a new texture optimization algorithm based on the reduction of the physical space allotted to the texture image. Our algorithm optimizes the use of texture space by computing a warping function for the image and new texture coordinates. Neither the mesh geometry nor its connectivity are modified by the optimization. Our method uniformly distributes frequency content of the image in the spatial domain. In other words, the image is stretched in high frequency areas, whereas low frequency regions are shrunk. We also take into account distortions introduced by the mapping onto the model geometry in this process. The resulting image can be resampled at lower rate while preserving its original details. The unwarping is performed by the texture mapping function. Hence, the space-optimized texture is stored as-is in texture memory and is fully supported by current graphics hardware. We present several examples showing that our method significantly decreases texture memory usage without noticeable loss in visual quality.
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    Sculpturing on Discrete Displacement Fields
    (Blackwell Publishers, Inc and the Eurographics Association, 2002) Ayasse, Jorg; Muller, Heinrich
    A displacement field can be defined by a vector field and a height field on an orientable surfaceS, describing the direction and the amount of displacement to be applied toSin order to get a surface represented by the displacement field.Stogether with the vector field can also be considered as a representation of a volume by a 'surface crust'. The crust allows the application of sculpturing operations for designing detailed structure. For conventional height fields over the plane, sculpturing can be reduced to the task of finding the minimum or maximum of the height values of a surface and the height values stored. Over the plane, depth-buffering with parallel projection has been used for calculation. For displacement fields over curved surfaces the projection is more complicated. In this contribution, an efficient solution is presented for displacement fields over triangular meshes. The central task is to insert a triangle in space into the curved depth-buffer represented by the displacement field.Categories and Subject Descriptors (according to ACM CCS): I.3.5 [Computational Geometry and Object Modeling]: Curve, surface, solid, and object representations
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    3D Scanning Technology: Capabilities and Issues
    (Blackwell Publishers, Inc and the Eurographics Association, 2002) Scopigno, Roberto
    The recent evolution of graphics technology makes it possible to manage very complex models on inexpensive platforms. These impressive rendering capabilities should be paired with detailed and accurate digital models. The construction of high quality 3D models is made easier by the increasing diffusion of automatic 3D measuring devices (often called 3D scanners). These allow to build highly accurate models of real 3D objects in a cost- and time-effective manner. The talk will present the capabilities of this technology focusing mainly on a particular application context: the acquisition of Cultural Heritage artifacts. The peculiar requirements of this domain (high accuracy in the acquisition of both shape and surface appearance, expected low cost and easiness of use of the tools) make it a perfect application example. This talk aims also at presenting and discussing the main issues in the acquisition of accurate 3D models, together with some limitations of current hardware and software tools. Some examples of the results of current projects will be shown.
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    Slow Growing Subdivision (SGS) in Any Dimension: Towards Removing the Curse of Dimensionality
    (Blackwell Publishers, Inc and the Eurographics Association, 2002) Pascucci, V.
    In recent years subdivision methods have been one of the most successful techniques applied to the multi-resolution representation and visualization of surface meshes. Extension these techniques to the volumetric case would enable their use in a broad class of applications including solid modeling, scientific visualization and mesh generation. Unfortunately, major challenges remain unsolved both in the generalization of the combinatorial structure of the refinement procedure and in the analysis of the smoothness of the limit mesh.In this paper we mainly tackle the first part of the problem introducing a subdivision scheme that generalizes to 3D and higher dimensional meshes without the excessive vertex proliferation typical of tensor-product refinements. The main four qualities of our subdivision procedure are: (i) the rate of refinement does not grow with the dimension of the mesh, (ii) adaptive refinement of the mesh is possible without introducing special temporary cell decompositions, (iii) the cells of the base meshes can have virtually unrestricted topology, and (iv) 'sharp' features of different dimensions can be incorporated naturally.We use a narrow averaging mask that is applied to the vertices of the mesh and/or to eventual functions defined on the mesh. The general study of the limit smoothness of the approach requires new analysis techniques that are beyond the scope of this paper.Categories and Subject Descriptors (according to ACM CCS): I.3.5 [Computer Graphics]: Curve, surface, solid, and object representations. Volumetric meshes, recursive subdivision methods.
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    Image-Swept Volumes
    (Blackwell Publishers, Inc and the Eurographics Association, 2002) Winter, Andrew S.; Chen, Min
    Many graphical objects can be represented by swept volumes (including its subset - generalised cylinders) by sweeping 2D or 3D templates along 3D trajectories. In this paper, we present a new approach for constructing swept volumes using image templates. We utilise scalar fields as our underlying data type, and employ volume ray casting techniques for rendering swept volumes in their original sweeping specifications as well as in their voxelised approximations. In addition to some simple image-swept volumes, we also treat multi-channel image templates, video templates, generalised sweeps, and self-intersecting trajectories. This approach enables us to model swept volumes with heterogeneous interiors and amorphous effects. It also facilitates the use of constructive volume geometry for creating complex scenes in both modelling and rendering space.
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    Object Space EWA Surface Splatting: A Hardware Accelerated Approach to High Quality Point Rendering
    (Blackwell Publishers, Inc and the Eurographics Association, 2002) Ren, Liu; Pfister, Hanspeter; Zwicker, Matthias
    Elliptical weighted average (EWA) surface splatting is a technique for high quality rendering of point-sampled 3D objects. EWA surface splatting renders water-tight surfaces of complex point models with high quality, anisotropic texture filtering. In this paper we introduce a new multi-pass approach to perform EWA surface splatting on modern PC graphics hardware, called object space EWA splatting. We derive an object space formulation of the EWA filter, which is amenable for acceleration by conventional triangle-based graphics hardware. We describe how to implement the object space EWA filter using a two pass rendering algorithm. In the first rendering pass, visibility splatting is performed by shifting opaque surfel polygons backward along the viewing rays, while in the second rendering pass view-dependent EWA prefiltering is performed by deforming texture mapped surfel polygons. We use texture mapping and alpha blending to facilitate the splatting process. We implement our algorithm using programmable vertex and pixel shaders, fully exploiting the capabilities of today's graphics processing units (GPUs). Our implementation renders up to 3 million points per second on recent PC graphics hardware, an order of magnitude more than a pure software implementation of screen space EWA surface splatting.Categories and Subject Descriptors (according to ACM CCS): I.3.3 [Computer Graphics]: Display Algorithms
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    Hybrid Geometric - Image Based Rendering
    (Blackwell Publishers, Inc and the Eurographics Association, 2002) Hidalgo, Eduardo; Hubbold, Roger J.
    We present a Hybrid Geometric-Image Based Rendering (HGIBR) system for displaying very complex geometrical models at interactive frame rates. Our approach replaces distant geometry with a combination of image-based representations and geometry, while rendering nearby objects from geometry. Reference images are computed on demand, which means that no pre-processing, or additional storage are necessary. We present results for a massive model of a whole offshore gas platform, to demonstrate that interactive frame rates can be maintained using the HGIBR approach. Our implementation runs on a pair of PCs, using commodity graphics hardware for fast 3D warping.
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    Multi-Resolution Rendering of Complex Animated Scenes
    (Blackwell Publishers, Inc and the Eurographics Association, 2002) Wand, M.; Strasser, W.
    We present a novel multi-resolution point sample rendering algorithm for keyframe animations. The algorithm accepts triangle meshes of arbitrary topology as input which are animated by specifying different sets of vertices at keyframe positions. A multi-resolution representation consisting of prefiltered point samples and triangles is built to represent the animated mesh at different levels of detail. We introduce a novel sampling and stratification algorithm to efficiently generate suitable point sample sets for moving triangle meshes. Experimental results demonstrate that the new data structure can be used to render highly complex keyframe animations like crowd scenes in real-time.Categories and Subject Descriptors: I.3.3 [Computer Graphics]: Picture / Image Generation - Display Algorithms; I.3.6 [Computer Graphics]: Methodology and Techniques - Graphics data structures and data types; G.3 [Mathematics of Computing]: Probability and Statistics - Probabilistic algorithms.
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    Automatic Integration of Facade Textures into 3D Building Models with a Projective Geometry Based Line Clustering
    (Blackwell Publishers, Inc and the Eurographics Association, 2002) Lee, Sung Chun; Jung, Soon Ki; Nevatia, Ram
    Visualization of city scenes is important for many applications including entertainment and urban mission planning. Models covering wide areas can be efficiently constructed from aerial images. However, only roof details are visible from aerial views; ground views are needed to provide details of the building facades for high quality 'fly-through' visualization or simulation applications. We present an automatic method of integrating facade textures from ground view images into 3D building models for urban site modeling. We first segment the input image into building facade regions using a hybrid feature extraction method, which combines global feature extraction with Hough transform on an adaptively tessellated Gaussian Sphere and local region segmentation. We estimate the external camera parameters by using the corner points of the extracted facade regions to integrate the facade textures into the 3D building models. We validate our approach with a set of experiments on some urban sites.Categories and Subject Descriptors (according to ACM CCS): I.3.3 [Computer Graphics]: Modeling packages
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    Representation of Pseudo Inter-reflection and Transparency by Considering Characteristics of Human Vision
    (Blackwell Publishers, Inc and the Eurographics Association, 2002) Matsuoka, H.; Takeuchi, T.; Kitazawa, H.; Onozawa, A.
    We have succeeded in developing a quick and fully automated system that can generate photo-realistic 3D CG data based on a real object. A major factor in this success comes from our findings through psychophysical experiments that human observers do not have an accurate idea of what should be actually reflected as inter-reflections on the surface of an object. Taking advantage of this characteristic of human vision, we propose a new inter-reflection representation technique in which inter-reflections are simulated by allowing the same quantity of reflection components as there are in the background to pass through the object. Since inter-reflection and transparency are calculated by the same algorithm, our system can capture 3D CG data from various real objects having a strong inter-reflection, such as plastic and porcelain items or translucent glass and acrylic resin objects. The synthetic images from the 3D CG data generated with this pseudo inter-reflection and transparency look very natural. In addition, the 3D CG data and synthetic images are produced quickly at a lower cost.
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    Dynamic Textures for Image-based Rendering of Fine-Scale 3D Structure and Animation of Non-rigid Motion
    (Blackwell Publishers, Inc and the Eurographics Association, 2002) Cobzas, Dana; Yerex, Keith; Jagersand, Martin
    The problem of capturing real world scenes and then accurately rendering them is particularly difficult for fine-scale 3D structure. Similarly, it is difficult to capture, model and animate non-rigid motion. We present a method where small image changes are captured as a time varying (dynamic) texture. In particular, a coarse geometry is obtained from a sample set of images using structure from motion. This geometry is then used to subdivide the scene and to extract approximately stabilized texture patches. The residual statistical variability in the texture patches is captured using a PCA basis of spatial filters. The filters coefficients are parameterized in camera pose and object motion. To render new poses and motions, new texture patches are synthesized by modulating the texture basis. The texture is then warped back onto the coarse geometry. We demonstrate how the texture modulation and projective homography-based warps can be achieved in real-time using hardware accelerated OpenGL. Experiments comparing dynamic texture modulation to standard texturing are presented for objects with complex geometry (a flower) and non-rigid motion (human arm motion capturing the non-rigidities in the joints, and creasing of the shirt).Categories and Subject Descriptors (according to ACM CCS): I.3.3 [Computer Graphics]: Image Based Rendering
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    A Simple and Robust Mutation Strategy for the Metropolis Light Transport Algorithm
    (Blackwell Publishers, Inc and the Eurographics Association, 2002) Kelemen, Csaba; Szirmay-Kalos, Laszlo; Antal, Gyorgy; Csonka, Ferenc
    This paper presents a new mutation strategy for the Metropolis light transport algorithm, which works in the unit cube of pseudo-random numbers instead of mutating in the path space. This transformation makes the integrand have lower variation and thus increases the acceptance probability of the mutated samples. Higher acceptance ratio, in turn, reduces the correlation of the samples, which increases the speed of convergence. We use both local mutations that choose a new random sample in the neighborhood of the previous one, and global mutations that make 'large steps', and find the samples independently. Local mutations smooth out the result, while global mutations guarantee the ergodicity of the process. Due to the fact that samples are generated independently in large steps, this method can also be considered as a combination of the Metropolis algorithm with a classical random walk. If we use multiple importance sampling for this combination, the combined method will be as good at bright regions as the Metropolis algorithm and at dark regions as random walks. The resulting scheme is robust, efficient, but most importantly, is easy to implement and to combine with an arbitrary random-walk algorithm.
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    Improved Scene Reconstruction from Range Images
    (Blackwell Publishers, Inc and the Eurographics Association, 2002) Wang, Jianning; Oliveira, Manuel M.
    The modeling of real scenes is a complex and challenging task for which the use of laser rangefinders is one of the most promising approaches. Unfortunately, in many situations, it is not possible or practical to guarantee appropriate sampling of all surfaces in the scene. For example, occlusions and accessibility limitations to certain regions of the scene may cause some areas not to be visible by the scanner, resulting in incomplete or incorrectly reconstructed models. This paper describes a pipeline and a system implementation for improving model reconstruction from incomplete information available from range images.Categories and Subject Descriptors (according to ACM CCS): I.3.7 [Computer Graphics]: Three-Dimensional Graphics and Realism, Virtual Reality
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    Grid Based Final Gather for Radiosity on Complex Clustered Scenes
    (Blackwell Publishers, Inc and the Eurographics Association, 2002) Scheel, Annette; Stamminger, Marc; Seidel, Hans-Peter
    Radiosity methods handle large scenes and complex objects using clustering techniques. To reconstruct a high quality image, usually a second very time consuming final gather pass is applied which exactly recomputes the last light transport before reaching the eye. We propose a new final gather technique which is especially suited for scenes with fine polygonal geometry. In such scenes, substantial parts of the incident illumination vary only smoothly across the surfaces and can be reconstructed on a much coarser structure. We therefore propose a final gather reconstruction based on an object-independent 3D grid. The illumination of each sender is investigated separately: If it varies smoothly across a grid cell, it is interpolated between the vertices of the grid cell, or recomputed exactly, otherwise. We further reduce the number of required samples using view-dependent optimizations. So complex objects with a very detailed structure-plants are good example here-exhibit strong masking effects, which can be exploited by our method. Finally, the estimation of penumbra screen sizes can be used to further reduce costly visibility reevaluations.Categories and Subject Descriptors (according to ACM CCS): I.3.3 [Copmuter Graphics]: Picture/Image generation I.3.7 [Copmuter Graphics]: Three-Dimensional Graphics and Realism
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    Advanced Radiance Estimation For Photon Map Global Illumination
    (Blackwell Publishers, Inc and the Eurographics Association, 2002) Hey, Heinrich; Purgathofer, Werner
    We present a new method to compute radiance in photon map based global illumination simulation for polygonal scenes with general bidirectional scattering distribution functions (BSDFs). Our new radiance estimation uses the actual geometry in the neighborhood of the illuminated point, and does not assume that the nearest neighbor photons lie in the same plane as the point, nor that they are distributed in a circular area around that point. This allows us to achieve accurate indirect illumination by direct visualization of the photon map - which is especially important for the simulation of caustics(LS+DS*Epaths) - even in the vicinity of edges and corners of objects, and on surfaces with differently oriented small geometric details.
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    Intrinsic Parameterizations of Surface Meshes
    (Blackwell Publishers, Inc and the Eurographics Association, 2002) Desbrun, Mathieu; Meyer, Mark; Alliez, Pierre
    Parameterization of discrete surfaces is a fundamental and widely-used operation in graphics, required, for instance, for texture mapping or remeshing. As 3D data becomes more and more detailed, there is an increased need for fast and robust techniques to automatically compute least-distorted parameterizations of large meshes. In this paper, we present new theoretical and practical results on the parameterization of triangulated surface patches. Given a few desirable properties such as rotation and translation invariance, we show that the only admissible parameterizations form a two-dimensional set and each parameterization in this set can be computed using a simple, sparse, linear system. Since these parameterizations minimize the distortion of different intrinsic measures of the original mesh, we call them Intrinsic Parameterizations. In addition to this partial theoretical analysis, we propose robust, efficient and tunable tools to obtain least-distorted parameterizations automatically. In particular, we give details on a novel, fast technique to provide an optimal mapping without fixing the boundary positions, thus providing a unique Natural Intrinsic Parameterization. Other techniques based on this parameterization family, designed to ease the rapid design of parameterizations, are also proposed.
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    Efficient Multidimensional Sampling
    (Blackwell Publishers, Inc and the Eurographics Association, 2002) Kollig, Thomas; Keller, Alexander
    Image synthesis often requires the Monte Carlo estimation of integrals. Based on a generalized concept of stratification we present an efficient sampling scheme that consistently outperforms previous techniques. This is achieved by assembling sampling patterns that are stratified in the sense of jittered sampling and N-rooks sampling at the same time. The faster convergence and improved anti-aliasing are demonstrated by numerical experiments.Categories and Subject Descriptors (according to ACM CCS): G.3 [Probability and Statistics]: Probabilistic Algorithms (including Monte Carlo); I.3.2 [Computer Graphics]: Picture/Image Generation; I.3.7 [Computer Graphics]: Three-Dimensional Graphics and Realism.
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    Free-form sketching with variational implicit surfaces
    (Blackwell Publishers, Inc and the Eurographics Association, 2002) Karpenko, Olga; Hughes, John F.; Raskar, Ramesh
    With the advent of sketch-based methods for shape construction, there's a new degree of power available in the rapid creation of approximate shapes. Sketch [Zeleznik, 1996] showed how a gesture-based modeler could be used to simplify conventional CSG-like shape creation. Teddy [Igarashi, 1999] extended this to more free-form models, getting much of its power from its 'inflation' operation (which converted a simple closed curve in the plane into a 3D shape whose silhouette, from the current point of view, was that curve on the view plane) and from an elegant collection of gestures for attaching additional parts to a shape, cutting a shape, and deforming it.But despite the powerful collection of tools in Teddy, the underlying polygonal representation of shapes intrudes on the results in many places. In this paper, we discuss our preliminary efforts at using variational implicit surfaces [Turk, 2000] as a representation in a free-form modeler. We also discuss the implementation of several operations within this context, and a collection of user-interaction elements that work well together to make modeling interesting hierarchies simple. These include 'stroke inflation' via implicit functions, blob-merging, automatic hierarchy construction, and local surface modification via silhouette oversketching. We demonstrate our results by creating several models.Categories and Subject Descriptors (according to ACM CCS): I.3.5 [Computer Graphics]: Modeling packages I.3.6 [Computer Graphics]: Interaction techniques
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    Hardware-Based Volumetric Knit-Wear
    (Blackwell Publishers, Inc and the Eurographics Association, 2002) Daubert, Katja; Seidel, Hans-Peter
    We present a hardware-based, volumetric approach for rendering knit wear at very interactive rates. A single stitch is represented by a volumetric texture with each voxel storing the main direction of the strands of yarn inside it. We render the knit wear in layers using an approximation of the Banks model. Our hardware implementation allows specular and diffuse material properties to change from one voxel to the next. This enables us to represent yarn made up of different components or render garments with complicated color patterns. Furthermore, our approach can handle self-shadowing of the stitches, and can easily be adapted to also include view-independent scattering. The resulting shader lends itself naturally to mip-mapping, and requires no reordering of the base geometry, making it versatile and easy to use.Categories and Subject Descriptors (according to ACM CCS): I.3.3 [Computer Graphics]: Hardware Applications Volumetric Textures
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    A Biologically-Parameterized Feather Model
    (Blackwell Publishers, Inc and the Eurographics Association, 2002) Streit, L.; Heidrich, W.
    Feathers, unlike other cutaneous appendages such as hair, fur, or scales have a definite structure. Variation in feather structure creates a wide range of resulting appearances. Collectively, feather structure determines the appearance of the feather coat, which can largely affect the resulting look of a feathered object (bird). In this paper we define the structure of individual feathers using a parameterization based on biological structure and substructures of actual feathers. We show that our parameterization can generate a large variety of feathers at multiple levels of detail and provide an initial step to semi-automatically generating a wide range of feather coats. his is achieved by specifying an intuitive interpolation between different structures and ages of feathers.
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    Designing 2D Vector Fields of Arbitrary Topology
    (Blackwell Publishers, Inc and the Eurographics Association, 2002) Theisel, H.
    We introduce a scheme of control polygons to design topological skeletons for vector fields of arbitrary topology. Based on this we construct piecewise linear vector fields of exactly the topology specified by the control polygons. This way a controlled construction of vector fields of any topology is possible. Finally we apply this method for topology-preserving compression of vector fields consisting of a simple topology.
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    Color Section
    (Blackwell Publishers Ltd and the Eurographics Association., 2002)
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    Hardware Accelerated Interactive Vector Field Visualization: A level of detail approach
    (Blackwell Publishers, Inc and the Eurographics Association, 2002) Bordoloi, Udeepta; Shen, Han-Wei
    This paper presents an interactive global visualization technique for dense vector fields using levels of detail. We introduce a novel scheme which combines an error-controlled hierarchical approach and hardware acceleration to produce high resolution visualizations at interactive rates. Users can control the trade-off between computation time and image quality, producing visualizations amenable for situations ranging from high frame-rate previewing to accurate analysis. Use of hardware texture mapping allows the user to interactively zoom in and explore the data, and also to configure various texture parameters to change the look and feel of the visualization. We are able to achieve sub-second rates for dense LIC-like visualizations with resolutions in the order of a million pixels for data of similar dimensions.Categories and Subject Descriptors (according to ACM CCS): I.3 [Computer Graphics]: Applications
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    Geometric Snakes for Triangular Meshes
    (Blackwell Publishers, Inc and the Eurographics Association, 2002) Lee, Y.; Lee, S.
    Feature detection is important in various mesh processing techniques, such as mesh editing, mesh morphing, mesh compression, and mesh signal processing. In spite of much research in computer vision, automatic feature detection even for images still remains a difficult problem. To avoid this difficulty, semi-automatic or interactive techniques for image feature detection have been investigated. In this paper, we propose a geometric snake as an interactive tool for feature detection on a 3D triangular mesh. A geometric snake is an extension of an image snake, which is an active contour model that slithers from its initial position specified by the user to a nearby feature while minimizing an energy functional. To constrain the movement of a geometric snake onto the surface of a mesh, we use the parameterization of the surrounding region of a geometric snake. Although the definition of a feature may vary among applications, we use the normal changes of faces to detect features on a mesh. Experimental results demonstrate that geometric snakes can successfully capture nearby features from user-specified initial positions.
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    Metamorphosis of Polyhedral Surfaces using Decomposition
    (Blackwell Publishers, Inc and the Eurographics Association, 2002) Shlafman, Shymon; Tal, Ayellet; Katz, Sagi
    This paper describes an algorithm for morphing polyhedral surfaces based on their decompositions into patches. The given surfaces need neither be genus-zero nor two-manifolds. We present a new algorithm for decomposing surfaces into patches. We also present a new projection scheme that handles topologically cylinder-like polyhedral surfaces. We show how these two new techniques can be used within a general framework and result with morph sequences that maintain the distinctive features of the input models.Categories and Subject Descriptors (according to ACM CCS): I.3.5 [Computational Geometry and Object Modeling]: Boundary representations I.3.7 [Three-Dimensional Graphics and Realism]: Animation
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    Flattening 3D objects using silhouettes
    (Blackwell Publishers, Inc and the Eurographics Association, 2002) Martin, D.; Fekete, J.D.; Torres, J. C.
    An important research area in non-photorealistic rendering is the obtention of silhouettes. There are many methods to do this using 3D models and raster structures, but these are limited in their ability to create stylised silhouettes while maintaining complete flexibility. These limitations do not exist in illustration, as each element is plane and the interaction between them can be eliminated by locating each one in a different layer. This is the approach presented in this paper: a 3D model is flattened into plane elements ordered in space, which allows the silhouettes to be drawn with total flexibility.Categories and Subject Descriptors (according to ACM CCS): I.3.3 [Computer Graphics]: Line and Curve Generation
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    Stylizing Silhouettes at Interactive Rates: From Silhouette Edges to Silhouette Strokes
    (Blackwell Publishers, Inc and the Eurographics Association, 2002) Isenberg, Tobias; Halper, Nick; Strothotte, Thomas
    A way to create effective stylized line drawings is to draw strokes that start and stop at visible portions along the silhouette of an object to be portrayed. In computer graphics to date, algorithms to extract silhouette edges are many, although putting these edges into a form such that stylized strokes may be applied to them has not been greatly covered, so that existing methods are either time-consuming or presented vaguely. In this paper, we introduce an algorithm that takes a set of silhouette edges originating from polygonal meshes and efficiently computes the visible parts of the edges before connecting them to form long smooth silhouette strokes to which stylization algorithms may be effectively applied. Features of our algorithm that gain efficiency and accuracy over existing methods is that we directly exploit the analytic connectivity information of the mesh in combination with the availablez-bufferinformation during rendering, and filter artifacts in connected edges during the process to improve the visual quality of strokes after stylization.Categories and Subject Descriptors (according to ACM CCS):1.3.3 [Computer Graphics]: Picture/Image Generation-Line and curve generation1.3.7 [Computer Graphics]: Three-Dimensional Graphics and Realism-Hidden line/surface removal
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    Modeling Surperspective Projection of Landscapes for Geographical Guide-Map Generation
    (Blackwell Science Ltd and the Eurographics Association, 2002) Takahashi, Shigeo; Ohta, Naoya; Nakamura, Hiroko; Takeshima, Yuriko; Fujishiro, Issei
    It is still challenging to generate hand-drawn pictures because they differ from ordinary photographs in that they are often drawn as seen from multiple viewpoints. This paper presents a new approach for modeling such surperspective projection based on shape deformation techniques. Specifically, surperspective landscape images for guide-maps are generated from 3D geographical elevation data. Our method first partitions a target geographical surface into feature areas to provide designers with landmarks suitable for editing. The system takes as input 2D visual effects, which are converted to 3D geometric constraints for geographical surface deformation. Using ordinary perspective projection, the deformed shape is then transformed into a target guide-map image where each landmark enjoys its own vista points. An algorithm for calculating such 2D visual effects semi-automatically from the geographical shape features is also considered.