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Multilevel representations and mesh reduction techniques have been used for accelerating the processing and the rendering of large datasets representing scalar or vector valued functions defined on complex 2 or 3 dimensional meshes. We present a method based on finite element approximations which combines these two approaches in a new and unique way that is(More)
Line Integral Convolution (LIC), introduced by Cabral and Leedom in 1993, is a powerful technique for generating striking images of vector data. Based on local ltering of an input texture along a curved stream line segment in a vector eld, it is possible to depict directional information of the vector eld at pixel resolution. The methods suggested so far(More)
In real applications the velocity field of a flow is not available in analytical but in discrete form. One goal of this paper is to analyze particle integration methods for discretized data defined on meshes with regard to numerical efficiency and accuracy. Careful error analysis of the particle tracing process relates the error of velocity interpolation in(More)
Visualization of volume data on the WWW using the Virtual Reality Modeling Language (VRML) and the Java programming language offers new perspectives for distributed and platform independent applications. A naive approach would either transfer the volume data to the client side for local processing or it would compute the iso-surface on the server side by a(More)
These days sparse grids are of increasing interest in numerical simulations. Based upon hierarchical tensor product bases, the sparse grid approach is a very eecient one improving the ratio of invested storage and computing time to the achieved accuracy for many problems in the area of numerical solution of diierential equations, for instance in numerical(More)
A multiresolution data decomposition offers a fundamental framework supporting compression, progressive transmission , and level-of-detail (LOD) control for large two or three dimensional data sets discretized on complex meshes. In this paper we extend a previously presented algorithm for 3D mesh reduction for volume data based on multilevel finite element(More)
An algorithm for adaptive refinement of 3D-meshes is outlined. This algorithm is very convenient for the generation of mesh hierarchies used for efficient volume visualiza-tion algorithms, e.g. iso-surface extraction or direct volume rendering, and for multilevel finite element computations. The aim was to construct an algorithm which generates as little(More)
We present a method for discretizing 3D-space in order to make it accessible for handling numerical problems , e.g. for simulation or visualization. Our algorithm generates a hierarchy of 3D meshes. It allows adaptive subdivision, driven by a user speciied local error control. Each 3D mesh consists of tetrahedra and octahedra having a minimal number of(More)