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Interactive volume visualization (i.e., the visualization of scalar
data defined on volumetric meshes in real time) is not only
difficult to achieve for large meshes but it is also complicated by
particular geometric features of volumetric meshes, e.g.,
non-uniform cells, non-convex boundaries, or visibility cycles.
This thesis addresses several of these geometric features and their
unpleasant consequences with respect to direct volume visualization,
which is one of the most successful techniques for interactive
volume visualization. In order to overcome, or at least alleviate,
these difficulties, several new algorithmic solutions are presented:
pre-integrated cell projection and hardware-assisted ray casting for
non-uniform meshes, edge collapses in non-convex meshes, cell
sorting and cell projection for non-convex and cyclic meshes, as
well as texture-based pre-integrated volume rendering,
topology-guided downsampling, and adaptive volume textures for
non-simplicial volumetric meshes (i.e., non-tetrahedral meshes).
As this work cannot cover all geometrically unpleasant features of
volumetric meshes, particular emphasis is put on a description of
the development of the proposed algorithms. In fact, most of the
presented techniques are (or may be interpreted as) generalizations,
adaptations, or extensions of existing methods. The intention of
explaining these origins is to motivate new solutions for those
geometrically unpleasant features of meshes that were out of the
scope of this work.
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