Results 1  10
of
26
A Near Optimal Isosurface Extraction Algorithm Using The Span Space
, 1996
"... We present the "Near Optimal IsoSurface Extraction" (NOISE) algorithm for rapidly extracting isosurfaces from structured and unstructured grids. Using the span space, a new representation of the underlying domain, we develop an isosurface extraction algorithm with a worst case complexity of O( p n ..."
Abstract

Cited by 174 (21 self)
 Add to MetaCart
We present the "Near Optimal IsoSurface Extraction" (NOISE) algorithm for rapidly extracting isosurfaces from structured and unstructured grids. Using the span space, a new representation of the underlying domain, we develop an isosurface extraction algorithm with a worst case complexity of O( p n + k) for the search phase, where n is the size of the data set and k is the number of cells intersected by the isosurface. The memory requirement is kept at O(n) while the preprocessing step is O(n log n). We utilize the span space representation as a tool for comparing isosurface extraction methods on structured and unstructured grids. We also present a fast triangulation scheme for generating and displaying unstructured tetrahedral grids. KeywordsIsosurface extraction, unstructured grids, span space, kdtrees I. Introduction Isosurface extraction is a powerful tool for investigating scalar fields within volumetric data sets. The position of an isosurface, as well as its relation to ...
Fast Isocontouring for Improved Interactivity
 In Proceedings of 1996 Symposium on Volume Visualization
, 1996
"... We present an isocontouringalgorithm which is nearoptimal for realtime interaction and modification of isovalues in large datasets. A preprocessing step selects a subset S of the cells which are considered as seed cells. Given a particular isovalue, all cells in S which intersect the given isocont ..."
Abstract

Cited by 120 (30 self)
 Add to MetaCart
We present an isocontouringalgorithm which is nearoptimal for realtime interaction and modification of isovalues in large datasets. A preprocessing step selects a subset S of the cells which are considered as seed cells. Given a particular isovalue, all cells in S which intersect the given isocontour are extracted using a highperformance range search. Each connected component is swept out using a fast isocontour propagation algorithm. The computational complexity for the repeated action of seed point selection and isocontour propagation is O(logn 0 + k), where n 0 is the size of S and k is the size of the output. In the worst case, n 0 = O(n), where n is the number of cells, while in practical cases, n 0 is smaller than n by one to two orders of magnitude. The general case of seed set construction for a convex complex of cells is described, in addition to a specialized algorithm suitable for meshes of regular topology, including rectilinear and curvilinear meshes. Keyword...
Speeding Up Isosurface Extraction using Interval Trees
, 1997
"... The interval tree is an optimally efficient search structure proposed by Edelsbrunner [5] to retrieve intervals of the real line that contain a given query value. We propose the application of such a data structure to the fast location of cells intersected by an isosurface in a volume dataset. The r ..."
Abstract

Cited by 102 (4 self)
 Add to MetaCart
The interval tree is an optimally efficient search structure proposed by Edelsbrunner [5] to retrieve intervals of the real line that contain a given query value. We propose the application of such a data structure to the fast location of cells intersected by an isosurface in a volume dataset. The resulting search method can be applied to both structured and unstructured volume datasets, and it can be applied incrementally to exploit coherence between isosurfaces. We also address issues about storage requirements, and operations other than the location of cells, whose impact is relevant in the whole isosurface extraction task. In the case of unstructured grids, the overhead due to the search structure is compatible with the storage cost of the dataset, and local coherence in the computation of isosurface patches is exploited through a hash table. In the case of a structured dataset, a new conceptual organization is adopted, called the chessboard approach, wich exploits the regular str...
View Dependent Isosurface Extraction
 In IEEE Visualization ’98
, 1998
"... We propose a new approach to polygonal isosurface extraction that is based on extracting only the visible portion of the isosurface. The visibility tests are done in two phases. First, coarse visibility tests are performed in software to determine the visible cells. These tests are based on hierarch ..."
Abstract

Cited by 70 (11 self)
 Add to MetaCart
We propose a new approach to polygonal isosurface extraction that is based on extracting only the visible portion of the isosurface. The visibility tests are done in two phases. First, coarse visibility tests are performed in software to determine the visible cells. These tests are based on hierarchical tiles and shearwarp factorization. The second phase resolves the visible portions of the extracted triangles and is accomplished by the graphics hardware. While the latest isosurface extraction methods have effectively eliminated the search phase bottleneck, the cost of constructing and rendering the isosurface remains high. Many of today's large datasets contain very large and complex isosurfaces that can easily overwhelm even stateoftheart graphics hardware. The proposed approach is output sensitive and is thus well suited for remote visualization applications where the extraction and rendering phases are done on a separate machines. 1 Introduction The marching cubes [11, 23] met...
Optimal Isosurface Extraction from Irregular Volume Data (Addendum)
, 1996
"... This document is available in .ps format at our web site (http://miles.cnuce.cnr.it/cg/bibliography.html). This workwas partially founded by the Progetto Coordinato "Modelli multirisoluzione per la visualizzazione di campi scalari multidimensionali" of the Italian National Research Council (CNR). We ..."
Abstract

Cited by 63 (5 self)
 Add to MetaCart
This document is available in .ps format at our web site (http://miles.cnuce.cnr.it/cg/bibliography.html). This workwas partially founded by the Progetto Coordinato "Modelli multirisoluzione per la visualizzazione di campi scalari multidimensionali" of the Italian National Research Council (CNR). We wish to thank those who have made available on the public domain the datasets used in the evaluation of the proposed techniques. References
Sweeping Simplices: A fast isosurface extraction algorithm for unstructured grids
 In IEEE Visualization '95
, 1995
"... We present an algorithm that accelerates the extraction of isosurfaces from unstructured grids by avoiding the traversal of the entire set of cells in the volume. The algorithm consists of a sweep algorithm and a data decomposition scheme. The sweep algorithm incrementally locates intersected eleme ..."
Abstract

Cited by 55 (8 self)
 Add to MetaCart
We present an algorithm that accelerates the extraction of isosurfaces from unstructured grids by avoiding the traversal of the entire set of cells in the volume. The algorithm consists of a sweep algorithm and a data decomposition scheme. The sweep algorithm incrementally locates intersected elements, and the data decomposition scheme restricts the algorithm's worstcase performance. For data sets consisting of hundreds of thousands of elements, our algorithm can reduce the cell traversal time more than 90% over the naive isosurface extraction algorithm, thus facilitating interactive probing of scalar fields for largescale problems on unstructured threedimensional grids. 1 Introduction Displaying isosurfaces is an effective way to visualize threedimensional scalar fields. Used to represent regions where the physical field is constant, isosurfaces allow visualization with a full range of visual depth. By visualizing the spatial distributions of several isosurfaces, scientists ar...
Hierarchical and Adaptive Visualization on Nested Grids
 Computing
, 1997
"... Zusammenfassung Hierarchical and Adaptive Visualization on Nested Grids. Modern numerical methods are capable to resolve fine structures in solutions of partial differential equations. Thereby they produce large amounts of data. The user wants to explore them interactively by applying visualization ..."
Abstract

Cited by 35 (5 self)
 Add to MetaCart
Zusammenfassung Hierarchical and Adaptive Visualization on Nested Grids. Modern numerical methods are capable to resolve fine structures in solutions of partial differential equations. Thereby they produce large amounts of data. The user wants to explore them interactively by applying visualization tools in order to understand the simulated physical process. Here we present a multiresolution approach for a large class of hierarchical and nested grids. It is based on a hierarchical traversal of mesh elements combined with an adaptive selection of the hierarchical depth. The adaptation depends on an error indicator which is closely related to the visual impression of the smoothness of isosurfaces or isolines, which are typically used to visualize data. Significant examples illustrate the applicability and efficiency on different types of meshes. Keywords : multiresolutional visualization, adaptive methods, error indicator, isosurfaces. Hierarchische und adaptive Visualisierung auf ges...
Over Two Decades of IntegrationBased, Geometric Flow
 EUROGRAPHICS 2009 / M. PAULY AND G. GREINER, STAR  STATE OF THE ART REPORT
, 2009
"... Flow visualization is a fascinating subbranch of scientific visualization. With ever increasing computing power, it is possible to process ever more complex fluid simulations. However, a gap between data set sizes and our ability to visualize them remains. This is especially true for the field of f ..."
Abstract

Cited by 31 (5 self)
 Add to MetaCart
Flow visualization is a fascinating subbranch of scientific visualization. With ever increasing computing power, it is possible to process ever more complex fluid simulations. However, a gap between data set sizes and our ability to visualize them remains. This is especially true for the field of flow visualization which deals with large, timedependent, multivariate simulation datasets. In this paper, geometry based flow visualization techniques form the focus of discussion. Geometric flow visualization methods place discrete objects in the vector field whose characteristics reflect the underlying properties of the flow. A great amount of progress has been made in this field over the last two decades. However, a number of challenges remain, including placement, speed of computation, and perception. In this survey, we review and classify geometric flow visualization literature according to the most important challenges when considering such a visualization, a central theme being the seeding object upon which they are based. This paper details our investigation into these techniques with discussions on their applicability and their relative merits and drawbacks. The result is an uptodate overview of the current stateoftheart that highlights both solved and unsolved problems in this rapidly evolving branch of research. It also serves as a concise introduction to the field of flow visualization research.
An Analysis of 3D Particle Path Integration Algorithms
 JOURNAL OF COMPUTATIONAL PHYSICS
, 1996
"... ..."
Visualization in Computational Fluid Dynamics: A Case Study
 IEEE Computer Society, Visualization
, 1991
"... VISUAL3 is a highlyinteractive environment for the visualization of 3D volumetric scientific data. The volume may be broken up in a structured or unstructured manner. Also, the problem may be static or unsteady in time. Because the data is volumetric (not just surfaces), and all the information can ..."
Abstract

Cited by 18 (7 self)
 Add to MetaCart
VISUAL3 is a highlyinteractive environment for the visualization of 3D volumetric scientific data. The volume may be broken up in a structured or unstructured manner. Also, the problem may be static or unsteady in time. Because the data is volumetric (not just surfaces), and all the information can be changing, traditional CAD techniques are not appropriate. Therefore VISUAL3 was developed using immediate mode rendering methods. A unique aspect of VISUAL3 is the dimensional windowing approach coupled with cursor mapping which allows efficient pointing in 3D space. VISUAL3 is composed of a large number of visualization tools that can be generally classified into identification, scanning and probing techniques. 1 Introduction The data produced by Computational Fluid Dynamics (CFD) codes creates many problems for visualization systems. The data is volumetric; in other words, the information of interest is throughout a volume and not just on a surface. This volume may be broken up in ma...