We introduce a novel texture-based volume rendering approach that achieves the image quality of the best post-shading approaches with far less slices. It is suitable for new flexible consumer graphics hardware and provides high image quality even for low-resolution volume data and non-linear transfer functions with high frequencies, without the performance overhead caused by rendering additional interpolated slices. This is especially useful for volumetric effects in computer games and professional scientific volume visualization, which heavily depend on memory bandwidth and rasterization power.We present an implementation of the algorithm on current programmable consumer graphics hardware using multi-textures with advanced texture fetch and pixel shading operations. We implemented direct volume rendering, volume shading, arbitrary number of isosurfaces, and mixed mode rendering. The performance does neither depend on the number of isosurfaces nor the definition of the transfer functions, and is therefore suited for interactive highquality volume graphics.

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Word clouds have emerged as a straightforward and visually appealing visualization method for text. They are used in various contexts as a means to provide an overview by distilling text down to those words that appear with highest frequency. Typically, this is done in a static way as pure text summarization. We think, however, that there is a larger potential to this simple yet powerful visualization paradigm in text analytics. In this work, we explore the usefulness of word clouds for general text analysis tasks. We developed a prototypical system called the Word Cloud Explorer that relies entirely on word clouds as a visualization method. It equips them with advanced natural language processing, sophisticated interaction techniques, and context information. We show how this approach can be effectively used to solve text analysis tasks and evaluate it in a qualitative user study.

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OpenGL and its extensions provide access to advanced per-pixel operations available in the rasterization stage and in the frame buffer hardware of modern graphics workstations. With these mechanisms, completely new rendering algorithms can be designed and implemented in a very particular way. In this paper we extend the idea of extensively using graphics hardware for the rendering of volumetric data sets in various ways. First, we introduce the concept of clipping geometries by means of stencil buffer operations, and we exploit pixel textures for the mapping of volume data to spherical domains. We show ways to use 3D textures for the rendering of lighted and shaded iso-surfaces in real-time without extracting any polygonal representation. Second, we demonstrate that even for volume data on unstructured grids, where only software solutions exist up to now, both methods, iso-surface extraction and direct volume rendering, can be accelerated to new rates of interactivity by simple polygon drawing and frame buffer operations.