DevLan/vispubs huggingface dataset:
View-dependent rendering of multiresolution texture-atlases
Authors: Henrik Buchholz, Jürgen Döllner
Published at Vis, 2005

Real-time rendering of massively textured 3D scenes usually involves two major problems: Large numbers of texture switches are a well-known performance bottleneck and the set of simultaneously visible textures is limited by the graphics memory. This paper presents a level-of-detail texturing technique that overcomes both problems. In a preprocessing step, the technique creates a hierarchical data structure for all textures used by scene objects, and it derives texture atlases at different resolutions. At runtime, our texturing technique requires only a small set of these texture atlases, which represent scene textures in an appropriate size depending on the current camera position and screen resolution. Independent of the number and total size of all simultaneously visible textures, the achieved frame rates are similar to that of rendering the scene without any texture switches. Since the approach includes dynamic texture loading, the total size of the textures is only limited by the hard disk capacity. The technique is applicable for any 3D scenes whose scene objects are primarily distributed in a plane, such as in the case of 3D city models or outdoor scenes in computer games. Our approach has been successfully applied to massively textured, large-scale 3D city models.
VisTrails: enabling interactive multiple-view visualizations
Authors: Louis Bavoil, Steven P. Callahan, Carlos Scheidegger, Huy T. Vo, Patricia Crossno, Cláudio T. Silva, Juliana Freire
Published at Vis, 2005

VisTrails is a new system that enables interactive multiple-view visualizations by simplifying the creation and maintenance of visualization pipelines, and by optimizing their execution. It provides a general infrastructure that can be combined with existing visualization systems and libraries. A key component of VisTrails is the visualization trail (vistrail), a formal specification of a pipeline. Unlike existing dataflow-based systems, in VisTrails there is a clear separation between the specification of a pipeline and its execution instances. This separation enables powerful scripting capabilities and provides a scalable mechanism for generating a large number of visualizations. VisTrails also leverages the vistrail specification to identify and avoid redundant operations. This optimization is especially useful while exploring multiple visualizations. When variations of the same pipeline need to be executed, substantial speedups can be obtained by caching the results of overlapping subsequences of the pipelines. In this paper, we describe the design and implementation of VisTrails, and show its effectiveness in different application scenarios.
Visual analysis and exploration of fluid flow in a cooling jacket
Authors: Robert S. Laramee, Christoph Garth, Helmut Doleisch, Jürgen Schneider, Helwig Hauser, Hans Hagen
Published at Vis, 2005

We present a visual analysis and exploration of fluid flow through a cooling jacket. Engineers invest a large amount of time and serious effort to optimize the flow through this engine component because of its important role in transferring heat away from the engine block. In this study we examine the design goals that engineers apply in order to construct an ideal-as-possible cooling jacket geometry and use a broad range of visualization tools in order to analyze, explore, and present the results. We systematically employ direct, geometric, and texture-based flow visualization techniques as well as automatic feature extraction and interactive feature-based methodology. And we discuss the relative advantages and disadvantages of these approaches as well as the challenges, both technical and perceptual with this application. The result is a feature-rich state-of-the-art flow visualization analysis applied to an important and complex data set from real-world computational fluid dynamics simulations.
Visualization in the Einstein Year 2005: a case study on explanatory and illustrative visualization of relativity and astrophysics
Authors: Daniel Weiskopf, Marc Borchers, Thomas Ertl, Martin Falk, Oliver Fechtig, Regine Frank, Frank Grave, Andreas King, Ute Kraus, Thomas Müller 0005, Hans-Peter Nollert, Isabel Rica Mendez, Hanns Ruder, Corvin Zahn, Michael Zatloukal, Tobias Schafhitzel, Sonja Schär
Published at Vis, 2005

In this application paper, we report on over fifteen years of experience with relativistic and astrophysical visualization, which has been culminating in a substantial engagement for visualization in the Einstein Year 2005 - the 100/sup th/ anniversary of Einstein's publications on special relativity, the photoelectric effect, and Brownian motion. This paper focuses on explanatory and illustrative visualizations used to communicate aspects of the difficult theories of special and general relativity, their geometric structure, and of the related fields of cosmology and astrophysics. We discuss visualization strategies, motivated by physics education and didactics of mathematics, and describe what kind of visualization methods have proven to be useful for different types of media, such as still images in popular-science magazines, film contributions to TV shows, oral presentations, or interactive museum installations. Although our visualization tools build upon existing methods and implementations, these techniques have been improved by several novel technical contributions like image-based special relativistic rendering on GPUs, an extension of general relativistic ray tracing to manifolds described by multiple charts, GPU-based interactive visualization of gravitational light deflection, as well as planetary terrain rendering. The usefulness and effectiveness of our visualizations are demonstrated by reporting on experiences with, and feedback from, recipients of visualizations and collaborators.
Visualization of the genus of knots
Authors: Jarke J. van Wijk, Arjeh M. Cohen
Published at Vis, 2005

The genus of a knot or link can be defined via Seifert surfaces. A Seifert surface of a knot or link is an oriented surface whose boundary coincides with that, knot or link. Schematic images of these surfaces are shown in every text book on knot theory, but from these it is hard to understand their shape and structure. In this paper the visualization of such surfaces is discussed. A method is presented to produce different styles of surfaces for knots and links, starting from the so-called braid representation. Also, it is shown how closed oriented surfaces can be generated in which the knot is embedded, such that the knot subdivides the surface into two parts. These closed surfaces provide a direct visualization of the genus of a knot.
Visualization of time-dependent remote adaptive mesh refinement data
Authors: Ralf Kähler, Steffen Prohaska, Andrei Hutanu, Hans-Christian Hege
Published at Vis, 2005

Analysis of phenomena that simultaneously occur on different spatial and temporal scales requires adaptive, hierarchical schemes to reduce computational and storage demands. Adaptive mesh refinement (AMR) schemes support both refinement in space that results in a time-dependent grid topology, as well as refinement in time that results in updates at higher rates for refined levels. Visualization of AMR data requires generating data for absent refinement levels at specific time steps. We describe a solution starting from a given set of "key frames" with potentially different grid topologies. The presented work was developed in a project involving several research institutes that collaborate in the field of cosmology and numerical relativity. AMR data results from simulations that are run on dedicated compute machines and is thus stored centrally, whereas the analysis of the data is performed on the local computers of the scientists. We built a distributed solution using remote procedure calls (RPC). To keep the application responsive, we split the bulk data transfer from the RPC response and deliver it asynchronously as a binary stream. The number of network round-trips is minimized by using high level operations. In summary, we provide an application for exploratory visualization of remotely stored AMR data.
Visualization of white matter tracts with wrapped streamlines
Authors: Frank Enders, Natascha Sauber, Dorit Merhof, Peter Hastreiter, Christopher Nimsky, Marc Stamminger
Published at Vis, 2005

Diffusion tensor imaging is a magnetic resonance imaging method which has gained increasing importance in neuroscience and especially in neurosurgery. It acquires diffusion properties represented by a symmetric 2nd order tensor for each voxel in the gathered dataset. From the medical point of view, the data is of special interest due lo different diffusion characteristics of varying brain tissue allowing conclusions about the underlying structures such as while matter tracts. An obvious way to visualize this data is to focus on the anisotropic areas using the major eigenvector for tractography and rendering lines for visualization of the simulation results. Our approach extends this technique to avoid line representation since lines lead 10 very complex illustrations and furthermore are mistakable. Instead, we generate surfaces wrapping bundles of lines. Thereby, a more intuitive representation of different tracts is achieved.
Visualization with stylized line primitives
Authors: Carsten Stoll, Stefan Gumhold, Hans-Peter Seidel
Published at Vis, 2005

Line primitives are a very powerful visual attribute used for scientific visualization and in particular for 3D vector-field visualization. We extend the basic line primitives with additional visual attributes including color, line width, texture and orientation. To implement the visual attributes we represent the stylized line primitives as generalized cylinders. One important contribution of our work is an efficient rendering algorithm for stylized lines, which is hybrid in the sense that it uses both CPU and GPU based rendering. We improve the depth perception with a shadow algorithm. We present several applications for the visualization with stylized lines among which are the visualizations of 3D vector fields and molecular structures.
Visualizing data with motion
Authors: Daniel E. Huber, Christopher G. Healey
Published at Vis, 2005

This paper describes an experimental study of three perceptual properties of motion: flicker, direction, and velocity. Our goal is to understand how to apply these properties to represent data in a visualization environment. Results from our experiments show that all three properties can encode multiple data values, but that minimum visual differences are needed to ensure rapid and accurate target detection: flicker must be coherent and must have a cycle length of 120 milliseconds or greater, direction must differ by at least 20/spl deg/, and velocity must differ by at least 0.43/spl deg/ of subtended visual angle. We conclude with an overview of how we are applying our results to real-world data, and then discuss future work we plan to pursue.
Visualizing intersecting surfaces with nested-surface techniques
Authors: Chris Weigle, Russell M. Taylor II
Published at Vis, 2005

This paper describes the adaptation and evaluation of existing nested-surface visualization techniques for the problem of displaying intersecting surfaces. For this work, we collaborated with a neurosurgeon who is comparing multiple tumor segmentations with the goal of increasing the segmentation accuracy and reliability. A second collaborator, a physicist, aims to validate geometric models of specimens against atomic-force microscope images of actual specimens. These collaborators are interested in comparing both surface shape and inter-surface distances. Many commonly employed techniques for visually comparing multiple surfaces (side-by-side, wireframe, colormaps, uniform translucence) do not simultaneously convey inter-surface distance and the shapes of two or more surfaces. This paper describes a simple geometric partitioning of intersecting surfaces that enables the application of existing nested-surface techniques, such as texture-modulated translucent rendering of exteriors, to a broader range of visualization problems. Three user studies investigate the performance of existing techniques and a new shadow-casting glyph technique. The results of the first user study show that texture glyphs on partitioned, intersecting surfaces can convey inter-surface distance better than directly mapping distance to a red-gray-blue color scale on a single surface. The results of the second study show similar results for conveying local surface orientation. The results of the third user study show that adding cast shadows to texture glyphs can increase the understanding of inter-surface distance in static images, but can be overpowered by the shape cues from a simple rocking motion.
Visualizing tensor fields in geomechanics
Authors: Alisa Neeman, Boris Jeremic, Alex T. Pang
Published at Vis, 2005

The study of stress and strains in soils and structures (solids) help us gain a better understanding of events such as failure of bridges, dams and buildings, or accumulated stresses and strains in geological subduction zones that could trigger earthquakes and subsequently tsunamis. In such domains, the key feature of interest is the location and orientation of maximal shearing planes. This paper describes a method that highlights this feature in stress tensor fields. It uses a plane-in-a-box glyph which provides a global perspective of shearing planes based on local analysis of tensors. The analysis can be performed over the entire domain, or the user can interactively specify where to introduce these glyphs. Alternatively, they can also be placed depending on the threshold level of several physical relevant parameters such as double couple and compensated linear vector dipole. Both methods are tested on stress tensor fields from geomechanics.
Visualizing the tightening of knots
Authors: Jason Cantarella, Michael Piatek, Eric J. Rawdon
Published at Vis, 2005

The study of physical models for knots has recently received much interest in the mathematics community. In this paper, we consider the ropelength model, which considers knots tied in an idealized rope. This model is interesting in pure mathematics, and has been applied to the study of a variety of problems in the natural sciences as well. Modeling and visualizing the tightening of knots in this idealized rope poses some interesting challenges in computer graphics. In particular, self-contact in a deformable rope model is a difficult problem which cannot be handled by standard techniques. In this paper, we describe a solution based on reformulating the contact problem and using constrained-gradient techniques from nonlinear optimization. The resulting animations reveal new properties of the tightening flow and provide new insights into the geometric structure of tight knots and links.
VolQD: direct volume rendering of multi-million atom quantum dot simulations
Authors: Wei Qiao, David S. Ebert, Alireza Entezari, Marek Korkusinski, Gerhard Klimeck
Published at Vis, 2005

In this work we present a hardware-accelerated direct volume rendering system for visualizing multivariate wave functions in semiconducting quantum dot (QD) simulations. The simulation data contains the probability density values of multiple electron orbitals for up to tens of millions of atoms, computed by the NEMO3-D quantum device simulator software run on large-scale cluster architectures. These atoms form two interpenetrating crystalline face centered cubic lattices (FCC), where each FCC cell comprises the eight corners of a cubic cell and six additional face centers. We have developed compact representation techniques for the FCC lattice within PC graphics hardware texture memory, hardware-accelerated linear and cubic reconstruction schemes, and new multi-field rendering techniques utilizing logarithmic scale transfer functions. Our system also enables the user to drill down through the simulation data and execute statistical queries using general-purpose computing on the GPU (GPGPU).
Volume rendering of smoke propagation CFD data
Authors: Oliver Staubli, Christian Sigg, Ronald Peikert, Markus H. Gross, Daniel Gubler
Published at Vis, 2005

The evacuation of buildings in the event of a fire requires careful planning of ventilation and evacuation routes during early architectural design stages. Different designs are evaluated by simulating smoke propagation using computational fluid dynamics (CFD). Visibility plays a decisive role in finding the nearest fire exit. This paper presents real-time volume rendering of transient smoke propagation conforming to standardized visibility distances. We visualize time dependent smoke particle concentration on unstructured tetrahedral meshes using a direct volume rendering approach. Due to the linear transfer function of the optical model commonly used in fire protection engineering, accurate pre-integration of diffuse color across tetrahedra can be carried out with a single 2D texture lookup. We reduce rounding errors during frame buffer blending by applying randomized dithering if high accuracy frame buffers are unavailable on the target platform. A simple absorption-based lighting model is evaluated in a preprocessing step using the same rendering approach. Back-illuminated exit signs are commonly used to indicate the escape route. As light emitting objects are visible further than reflective objects, the transfer function in front of illuminated exit signs must be adjusted with a deferred rendering pass.
VolumeExplorer: roaming large volumes to couple visualization and data processing for oil and gas exploration
Authors: Laurent Castanie, Bruno Lévy 0001, Fabien Bosquet
Published at Vis, 2005

In this paper, we present a volume roaming system dedicated to oil and gas exploration. Our system combines probe-based volume rendering with data processing and computing. The daily oil production and the estimation of the world proven-reserves directly affect the barrel price and have a strong impact on the economy. Among others, production and correct estimation are linked to the accuracy of the sub-surface model used for predicting oil reservoirs shape and size. Geoscientists build this model from the interpretation of seismic data, i.e. 3D images of the subsurface obtained from geophysical surveys. Our system couples visualization and data processing for the interpretation of seismic data. It is based on volume roaming along with efficient volume paging to manipulate the multi-gigabyte data sets commonly acquired during seismic surveys. Our volume rendering lenses implement high quality pre-integrated volume rendering with accurate lighting. They use a generic multi-modal volume rendering system that blends several volumes in the spirit of the "stencil" paradigm used in 2D painting programs. In addition, our system can interactively display non-polygonal isosurfaces painted with an attribute. Beside the visualization algorithms, automatic extraction of local features of the subsurface model also take full advantage of the volume paging.
VolumeShop: an interactive system for direct volume illustration
Authors: Stefan Bruckner, M. Eduard Gröller
Published at Vis, 2005

Illustrations play a major role in the education process. Whether used to teach a surgical or radiologic procedure, to illustrate normal or aberrant anatomy, or to explain the functioning of a technical device, illustration significantly impacts learning. Although many specimens are readily available as volumetric data sets, particularly in medicine, illustrations are commonly produced manually as static images in a time-consuming process. Our goal is to create a fully dynamic three-dimensional illustration environment which directly operates on volume data. Single images have the aesthetic appeal of traditional illustrations, but can be interactively altered and explored. In this paper we present methods to realize such a system which combines artistic visual styles and expressive visualization techniques. We introduce a novel concept for direct multi-object volume visualization which allows control of the appearance of inter-penetrating objects via two-dimensional transfer functions. Furthermore, a unifying approach to efficiently integrate many non-photorealistic rendering models is presented. We discuss several illustrative concepts which can be realized by combining cutaways, ghosting, and selective deformation. Finally, we also propose a simple interface to specify objects of interest through three-dimensional volumetric painting. All presented methods are integrated into VolumeShop, an interactive hardware-accelerated application for direct volume illustration.
A note on space-filling visualizations and space-filling curves
Authors: Martin Wattenberg
Published at InfoVis, 2005

A recent line of treemap research has focused on layout algorithms that optimize properties such as stability, preservation of ordering information, and aspect ratio of rectangles. No ideal treemap layout algorithm has been found, and so it is natural to explore layouts that produce nonrectangular regions. This note describes a connection between space-filling visualizations and the mathematics of space-filling curves, and uses that connection to characterize a family of layout algorithms which produce nonrectangular regions but enjoy geometric continuity under changes to the data and legibility even for highly unbalanced trees.
A sky dome visualisation for identification of astronomical orientations
Authors: Georg Zotti, M. Eduard Gröller
Published at InfoVis, 2005

It has long been known that ancient temples were frequently oriented along the cardinal directions or to certain points along the horizon where Sun or Moon rise or set on special days of the year. In the last decades, archaeologists have found evidence of even older building structures buried in the soil, with doorways that also appear to have distinct orientations. This paper presents a novel diagram combining archaeological maps with a folded-apart, flattened view of the whole sky, showing the local horizon and the daily paths of Sun, Moon and brighter stars. By use of this diagram, interesting groupings of astronomical orientation directions, e.g. to certain Sunrise and Sunset points could be identified, which were evidently used to mark certain days of the year. Orientations to a few significant stars very likely indicated the beginning of the agricultural year in the middle neolithic period
Adapting the cognitive walkthrough method to assess the usability of a knowledge domain visualization
Authors: Kenneth R. Allendoerfer, Serge Aluker, Gulshan Panjwani, Jason M. Proctor, David Sturtz, Mirjana Vukovic, Chaomei Chen
Published at InfoVis, 2005

The usability of knowledge domain visualization (KDViz) tools can be assessed at several levels. Cognitive walkthrough (CW) is a well known usability inspection method that focuses on how easily users can learn software through exploration. Typical applications of CW follow structured tasks where user goals and action sequences that lead to achievement of the goals are well defined. KDViz and other information visualization tools, however, are typically designed for users to explore data and user goals and actions are less well understood. In this paper, we describe how the traditional CW method may be adapted for assessing the usability of these systems. We apply the adapted version of CW to CiteSpace, a KDViz tool that uses bibliometric analyses to create visualizations of scientific literatures. We describe usability issues identified by the adapted CW and discuss how CiteSpace supported the completion of tasks, such as identifying research fronts, and the achievement of goals. Finally, we discuss improvements to the adapted CW and issues to be addressed before applying it to a wider range of KDViz tools.