EG2000

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https://diglib.eg.org/handle/10.2312/218

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A Facial Repertoire for Animation
(Eurographics Association, 2000) ten Hagen, Paul J. W.
Character design and facial animation of characters is among the most tedious parts of creation of animations. In contrast to body animations, performer data have not been successfully used for faces. The CharToon system provides a facility to create a powerful repertoire of reusable components at several levels for the construction of faces and face animations. The knowledge embedded in the system allows for reuse of facial architectures, motion methods and animation definitions for newly constructed or adapted faces. These methods cover among other things, expressions, speech animations and changing view points. This paper describes the organization of the repertoire, how it can be built and extended, and gives examples of its usage. The repertoire offers a perspective of how a higher level system of animation behaviors can be created on top. The presentation will show many animated examples of the contents and working of the repertoire.
Interactive 3D Rendering and Visualization in Networked Environments
(Eurographics Association, 2000) Martin, Ioana M.; Klosowski, James T.; Horn, William P.
Efficient delivery of 3D graphics over networks is becoming increasingly important for a number of applications, ranging from industrial design and manufacturing to entertainment. As companiesmake the transition from a conventional business model to an e-business model, the number of users that require access to 3D model databases is forecast to grow dramatically over the next few years.While some usersmay access these databases using highperformance graphics hardware over high-speed connections, others are likely to access the data with devices having limited hardware graphics support over slower connections such as busy intranets, dial-in networks, or wireless connections. In this context, there is a requirement for efficiency. This translates into ensuring that access to centralized data is provided through a unified interface cognizant of the environment conditions and capable of transparently adjusting the access mechanism in order to provide the clients with optimal access service. In this course, attendees will learn to leverage existing methods for data transfer and interactive graphics to create the next generation of 3D networked graphics software tools.
Volume Visualization and Volume Rendering Techniques
(Eurographics Association, 2000) Meißner, M.; Pfister, H.; Westermann, R.; Wittenbrink, C.M.
There is a wide range of devices and scientific simulation generating volumetric data. Visualizing such data, ranging from regular data sets to scattered data, is a challenging task. This course will give an introduction to the volume rendering transport theory and the involved issues such as interpolation, illumination, classification and others. Different volume rendering techniques will be presented illustrating their fundamental features and differences as well as their limitations. Furthermore, acceleration techniques will be presented including pure software optimizations as well as utilizing special purpose hardware as VolumePro but also dedicated hardware such as polygon graphics subsystems.
Interactive Modelling of Convolution Surfaces with an Extendable User Interface
(Eurographics Association, 2000) Goto, Yuichiro; Pasko, Alexander
Convolution surfaces enable the user to model complex free-form shapes. Due to analytical solutions for some kernel functions and skeletal elements, it is possible to model convolution surfaces interactively. An extendable user interface allows the user to design models using different types of convolution surfaces. New primitives can be easily bound to the modeller using the proposed binding technique. Models generated in HyperFun language can be exchanged between modelling tools on several platforms.
Component Based Human Animation Architecture
(Eurographics Association, 2000) Jing, Huang; Fi, Chin Kah; Prakash, Edmond C.
This paper describes a method to predict the free reach movement of different components of the human body. Since the human body is composed of the following components: arms, legs, torso, head & neck, and each of these components has similar features, the same geometric inverse kinematics algorithm can be used in different parts of the body to realize free reach movement task. The main advantage of the proposed method is that it avoids matrix inverse calculation, which is very time consuming. And by using this method, the task can be mostly simplified.
Framework Technologies and Methods for Large Data Visualization
(Eurographics Association, 2000) Hewitt, W. T.; Curington,Ian
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A Procedural Approach to Solving Constraints of Articulated Bodies
(Eurographics Association, 2000) Lee, J. Won; Baek, Nakhoon; Kim, Dongho; Hahn, James K.
Realistic motions of articulated bodies are usually generated by using physically-based animation methods such as constrained dynamics. However, these methods involve heavy computations and complicated numerical methods. We present an alternative way of solving constraints of articulated bodies. Our objective is not physically correct motions but visually plausible animation. In our method, each object of the constrained body is first moved according to their physical parameters and external forces, without considering any constraints. Then the objects are translated and rotated to satisfy the given constraints. Instead of strict simulation of physical laws, we suggest procedural formulations for solving constraints. This formulation has the power of generating visually plausible motions as presented in our example animation sequences. Since our method is free from complex numerical methods, it is fast enough to be used in real-time applications such as virtual reality, computer games and real-time simulations. Numerical stability is another merit of our method. This procedural approach can be an alternative to strict physically-based animation methods.
Imaging Geometry for Concentric Mosaics
(Eurographics Association, 2000) Watson, G. C.; Vaughan, N.; Wright, M. W.
Image-based models of environments can be captured with the use of a rotating video camera. In this paper we consider the nature of the display to develop a simple quantitative measure of the quality of ray sampling which we use to compare different imaging geometries for concentric mosaics. We propose a novel arrangement for the rotating camera, which we show to produce a better sampling of rays for viewing on displays where the display surface is fixed in space and the view position is varied. We show how this improved capture geometry can be employed in a head tracked display to produce a display that resembles a virtual window through which a captured environment can be viewed.
Selecting Effective Occluders for Visibility Culling
(Eurographics Association, 2000) Koltun, Vladlen; Cohen-Or, Daniel
This paper deals with the problem of identifying effective occluders for visibility culling. The solid-angle metric is commonly used for measuring the potential significance of occluders from a single viewpoint. In this paper, we show that it does not extend properly to from-region occlusion calculations. We propose to measure the effectiveness of an occluder by means of the size of its umbra. We first present an analytic object-space algorithm to accurately compute this measure. We then define an approximation which reflects the effectiveness of an occluder, and introduce a hardware-assisted algorithm to rapidly compute it.
Spreading of the cultural heritage by means of multi-configurable, low cost virtual reality techniques
(Eurographics Association, 2000) Flores, J.; Arias, J.; Saavedra, S.; Varela, E.; Ferro, J. M.; Taboada, J.
In the last few years, computer graphics techniques have been applied to preserve and promote the cultural heritage. In this first steps the bottleneck of these applications developed was the price of the hardware that limited the use of these tools to museums or exhibition rooms. Nevertheless, the fast increase of graphic capacity of the computers allows the development of high -quality complex applications which can be visualized in personal computers. This is completed by multidisciplinary research groups that focus their efforts on the most relevant aspect of the learning and presence sense in virtual environments. In this paper, an application of V.R. techniques to the promotion of heritage patrimony bases, in a PC platform, is presented. Focus has been put into high screen quality, multiple screen, multi-user, stereoscopic image, 3D sound and multisensorial environments as well as the high transportability, scalability and low price aiming at a quite widespread use of this hardware. The virtual reality application developed shows the old part of Santiago de Compostela, European City of Culture for the year 2000. The model of t he city is complex enough to prove that it is possible to use PC´s as visualization engine, over high quality and complex models.
Volumetric Textures
(Eurographics Association, 2000) Gonzalez Clua, Esteban W.; Dreux, Marcelo
There are some types of nature elements that are adequately represented in Computer Graphics only through volumes. In order to visualize scenes with volumes, together with geometrical objects, it is necessary to make use of a hybrid rendering algorithm. However, the presence of volumetric elements heavily increases the visualization processing time, independently of the technique being used. This article presents a method that is being developed in order to reduce the volumetric rendering to a projection of a special texture on a geometric surface that surrounds the volume. This technique seems to be particularly efficient to volumes that represent nature elements, such as gases, clouds and smoke. It is possible, however, to extend the method to other types of volumetric objects.
Efficient Evaluation of the Field Functions of Soft Objects Using Interval Tree
(Eurographics Association, 2000) Min, Kyung-Ha; Lee, In-Kwon; Park, Chan-Mo
We present an algorithm to evaluate the field function of a soft object efficiently. Instead of using a global field function that is defined by the sum of all local field functions, we consider only the set of local field functions that affects a point at which we want to evaluate the field function. To find the affecting local field functions efficiently, we exploit a data structure called interval tree based on the bounding volume of the component corresponding to the primitives (skeletons) of a soft object. The bounding volume of each component is generated with respect to the radius of a local field function of the component, threshold value, and the relations between the components and other neighboring components. The proposed scheme of field function evaluation can be used in many applications for soft objects such as modeling and rendering, especially in interactive modeling process.
Interactive Display of Global Illumination Solutions for Non-Diffuse Environments
(Eurographics Association, 2000) Heidrich, Wolfgang
In recent years there has been a lot of work on interactively displaying global illumination solutions for nondiffuse environments. This is an extremely active field of research, in which a lot of different approaches have been proposed recently. In this State-of-The-Art-Report, we will discuss and compare these. This will hopefully lay the ground for systematically addressing the open questions in the future.
Dealing with Shape Complexity for Internet Access and Graphic Applications
(Eurographics Association, 2000) Rossignac, Jarek
Standard representations of 3D models are so verbose that only very simple models can be accessed over common communication links for immediate viewing. This situation is not likely to improve, since the need for more accurate 3D models and their deployment throughout a broader spectrum of industrial, scientific, and consumer application areas will outpace the improvements in transmission bandwidth to the office, home, or mobile worker or private user. Recently developed multi-resolution modeling technologies play an important role in addressing this bandwidth bottleneck, especially when combined with other approaches, such as intelligent culling, pre-fetching, and image-based rendering. This tutorial will discuss the details of compression, simplification, and progressive transmission techniques and of their interrelations.
ALOHA : Adaptive Level Of Detail for Human Animation Towards a new framework
(Eurographics Association, 2000) Giang, Thanh; Mooney, Robert; Peters, Christopher; Sullivan, Carol O.
The task of animating and rendering virtual humans in real-time is challenging. One must first establish a sense of realism through appearance, and then maintain this realism through correct and plausible motion, while continually satisfying the real-time constraint imposed. One technique that aids in achieving such a task is to take advantage of the viewer’s perception to compute less accurate models when loss of accuracy is unlikely to be noticed. Traditionally, these ‘level of detail’ techniques have been used primarily for geometric modelling. However, more recently, they have also been applied to animation. This paper seeks to amalgamate animation and geometric level of detail research in order to produce an integrated framework on which to build a totally scalable system for virtual human animation.
Visibility Complexity of a Region in Flatland
(Eurographics Association, 2000) Rigau, Jaume; Feixas, Miquel; Sbert, Mateu
The aim of this paper is to study the visibility complexity of different regions in a 2D scene. Based on mutual information, which we used in our previous work to define scene complexity, we propose two measures that quantify the complexity of a region from two different points of view. The knowledge of the complexity of a region can be useful to determine how difficult it is to recompute the visibility links for an animation depending on the regions visited or to obtain the complexity of the movement of a robot. We also envisage its applicability to obtain an optimal load balancing in a parallel computation by dividing the geometry in equal complexity regions.
Recent Advances in Visualization of Volumetric Data
(Eurographics Association, 2000) Brodlie, Ken; Wood, Jason
In the past few years, there have been key advances in the three main approaches to the visualization of volumetric data: isosurfacing, slicing and volume rendering, which together make up the field of volume visualization. In this report we set the scene by describing the fundamental techniques for each of these approaches, using this to motivate the range of advances which have evolved over the past few years. In isosurfacing, we see how the original marching cubes algorithm has matured, with improvements in robustness, topological consistency, accuracy and performance. In the performance area, we look in detail at pre-processing steps which help identify data which contributes to the particular isosurface required. In slicing too, there are performance gains from identifying active cells quickly. In volume rendering, we describe the two main approaches of ray casting and projection. Both approaches have evolved technically over the past decade, and the holy grail of real-time volume rendering has arguably been reached. The aim of this Eurographics 2000 STAR is to pull these developments together in a coherent review of recent advances in volume visualization.
The 3D Model Acquisition Pipeline
(Eurographics Association, 2000) Bernardini, Fausto; Rushmeier, Holly
Three-dimensional image acquisition systems are rapidly becoming more affordable, especially systems based on commodity electronic cameras. At the same time, personal computers with graphics hardware capable of displaying complex 3D models are also becoming inexpensive enough to be available to a large population. As a result, there is potentially an opportunity to consider new virtual reality applications as diverse as cultural heritage and retail sales that will allow people to view realistic 3D objects on home computers. Although there are many physical techniques for acquiring 3D data – including laser scanners, structured light and time-of-flight – there is a basic pipeline of operations for taking the acquired data and producing a usable numerical model. We look at the fundamental problems of range image registration, line-of-sight errors, mesh integration, surface detail and color, and texture mapping. In the area of registration we consider both the problems of finding an initial global alignment using manual and automatic means, and refining this alignment with variations of the Iterative Closest Point methods. To account for scanner light-of-sight errors we compare averaging and conformance approaches. In the area of mesh integration, that is finding a single mesh joining the data from all scans, we compare various methods for computing interpolating and approximating surfaces. We then look at various ways in which surface properties such as color (more properly, spectral reflectance) can be extracted from acquired imagery. Finally, we examine techniques for a producing a final model representation that can be efficiently rendered using graphics hardware.
Discrete Analysis for Antialiased Lines
(Eurographics Association, 2000) Boyer, V.; Bourdin, J. J.
This paper presents a new fast and smooth antialiasing technique. Drawing straight line is the graphic tool’s main primitive. Previous antialiasing techniques improve smoothness but slow down computation.
Principles of Computer Graphics: the experience of a class A user
(Eurographics Association, 2000) Cailliau, Robert
Computer graphics has gone a long way from the early days in the 50’s and 60’s. Today we have the web, and it’s all visual that is the fashion. What does an unsuspecting user of computers, who is not a specialist, actually experience? Where are we when we leave the 3D interactive shooting game world and we want to do some simple things?

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