Virtual Tubelets-efficiently visualizing large amounts of particle trajectories

The depiction of particle trajectories is an effective means for the visualization of fluid flows. However, standard visualization techniques suffer from a variety of weaknesses, ranging from ambiguous depth perception for simple line drawings to a high geometrical complexity and decreased interactivity for polygonal tubes. This paper addresses these problems by introducing a novel approach to pathline visualization, which we call Virtual Tubelets. It employs billboarding techniques in combination with suitable textures in order to create the illusion of solid tubes, thus efficiently and unambiguously depicting large amounts of particle trajectories at interactive frame rates. By choosing an appropriate orientation for the billboards, certain issues concerning immersive displays with multiple projection screens are resolved, which allows for an unrestricted use in virtual environments as well. Using modern graphics hardware with programmable vertex and pixel pipelines results in an additional speed-up of the rendering process and a further improvement of image quality. This creates a nearly perfect illusion of tubular geometry, including plausible intersections and consistent illumination with the rest of the scene. The efficiency of our approach is proven by comparing rendering speed and visual quality of Virtual Tubelets to that of conventional, polygonal tube renderings.