title: Ambient occlusion effects for combined volumes and tubular geometry.
abstract: This paper details a method for interactive direct volume rendering that computes ambient occlusion effects for visualizations that combine both volumetric and geometric primitives, specifically tube-shaped geometric objects representing streamlines, magnetic field lines or DTI fiber tracts. The algorithm extends the recently presented the directional occlusion shading model to allow the rendering of those geometric shapes in combination with a context providing 3D volume, considering mutual occlusion between structures represented by a volume or geometry. Stream tube geometries are computed using an effective spline-based interpolation and approximation scheme that avoids self-intersection and maintains coherent orientation of the stream tube segments to avoid surface deforming twists. Furthermore, strategies to reduce the geometric and specular aliasing of the stream tubes are discussed.
authors.affiliation: NVIDIA corporation, 2701 San Tomas Expressway, Santa Clara, CA 95050, USA. mschott@nvidia.com
authors.forename: Mathias
authors.initials: M
authors.lastname: Schott
authors.forename: Tobias
authors.initials: T
authors.lastname: Martin
authors.forename: A V Pascal
authors.initials: AV
authors.lastname: Grosset
authors.forename: Sean T
authors.initials: ST
authors.lastname: Smith
authors.forename: Charles D
authors.initials: CD
authors.lastname: Hansen
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