Constructing Streak Surfaces for 3D Unsteady Vector Fields

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Abstract: Visualization of 3D, unsteady flow (4D) is very difficult due to both perceptual challenges and the large size of 4D vector field data. One approach to this challenge is to use integral surfaces to visualize the 4D properties of the field. However the construction of streak surfaces has remained elusive due to problems stemming from expensive computation and complex meshing schemes. We present a novel streak surface construction algorithm that generates the surface using a quadrangular mesh. In contrast to previous approaches the algorithm offers a combination of speed for exploration of 3D unsteady flow, high precision, and places less restriction on data or mesh size due to its CPU-based implementation compared to a GPU-based method. The algorithm can be applied to large data sets because it is based on local operations performed on the quad primitives. We demonstrate the technique on a variety of 3D, unsteady simulation data sets to show its speed and robustness. We also present both a detailed implementation and a performance evaluation. We show that a technique based on quad meshes handles large data sets and can achieve interactive frame rates.
Paper Images: (Click on images for higher resolution version)
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A complete streak surface depicting flow past a cuboid. The evolution of complex can be seen as the simulation progresses. Color is mapped to velocity magnitude. The full animation sequence is available in the supplementary video.

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A streaksurface depicting a tornado simulation. The surface encounters large amounts of shear that accumulate as the simulation progresses.

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A streak surface on the Ionization Front Instability simulation (from the IEEE Vis'08 contest). This is a turbulent data set with 200 timesteps at a resolution of 600x248x248.

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This image depicts the surface generated from the full resolution (500x500x100x48) of the Hurricane Isabel simulation. In this image we stop seeding the surface after a period of time and advect the sheet. Here the sheet is caught by the eye of the Hurricane.

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A streak surface of the simulation of flow past a square cylinder. The image shows a late stage into the simulation and shows the complete surface exhibiting divergence, convergence, shear and splitting behavior.

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Even under strong deformation, the mesh remains well-structured and produces a smooth surface. This image also demonstrates the use of triangle fans to render quads that contain t-junctions.


This page is maintained by Tony McLoughlin.
In case of comments, questions, suggestions, or collaboration ideas, please send email to: cstony "at" swansea.ac.uk.

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