NVIDIA corporation, 2701 San Tomas Expressway, Santa Clara, CA 95050, USA.
IEEE Trans Vis Comput Graph. 2013 Jun;19(6):913-26. doi: 10.1109/TVCG.2012.306.
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.
本文详细介绍了一种用于交互式直接体绘制的方法，该方法可计算组合体绘制和几何基元（具体为表示流线、磁场线或 DTI 纤维束的管状几何对象）的可视化环境光遮挡效果。该算法扩展了最近提出的方向遮挡着色模型，以允许在考虑体积或几何结构之间的相互遮挡的情况下，结合提供 3D 体积的上下文来渲染这些几何形状。流管几何形状使用有效的基于样条的插值和逼近方案来计算，该方案避免了自相交并保持流管段的一致方向，以避免表面变形扭曲。此外，还讨论了减少流管的几何和镜面伪影的策略。
