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Glyph and Streamline Placement Algorithms for CFD Simulation Data. Zhenmin Peng 1 , Robert S. Laramee 1 , Guoning Chen 2 , and Eugene Zhang 2. 1 The Visual and Interactive Computing Group Computer Science Dept. Swansea University Swansea, Wales, UK {cszp, r.s.laramee } “at” swansea.ac.uk.
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Glyph and Streamline Placement Algorithms for CFD Simulation Data Zhenmin Peng1, Robert S. Laramee1, Guoning Chen2, and Eugene Zhang2 1The Visual and Interactive Computing Group Computer Science Dept. Swansea University Swansea, Wales, UK {cszp, r.s.laramee } “at” swansea.ac.uk 2School of Electrical Engineering and Computer Science, Oregon State University Corvallis, OR 97331. {chengu,zhange} “at” eecs.oregonstate.edu. 1http://cs.swan.ac.uk/~csbob/
2http://cs.swan.ac.uk/~csbob/ Overview • Challenges Posed by Simulation Data • Flow Visualization: An Introduction • Visualization Using Glyphs • Problems • Solution: User Options and Demonstration • Flow Visualization with Streamlines • Seeding Problem Streamlines • Problems and Challenges • User Options and Demonstration • Conclusions and Summary
3http://cs.swan.ac.uk/~csbob/ Challenges Posed by CFD Simulation Data • Engineers often start with boundary surface when investigating simulation results. • Meshes Used in CFD Simulation: • complex • unstructured • adaptive resolution
4http://cs.swan.ac.uk/~csbob/ What is Flow Visualization? • A classic topic within scientific visualization • Depiction of vector quantities (as opposed to scalar quantities) • Applications include automotive simulation, aerodynamics, turbo machinery, meteorology, oceanography, medical visualization • Challenges: • To effectively visualize both magnitude + direction, often simultaneously • Large, time-dependent data sets • Interaction, seeding, and placement, • Computation time and irregular grids • Perception
5http://cs.swan.ac.uk/~csbob/ Flow Visualization Using Glyphs: Problem Naïve approach: place arrow glyph at each sample point on mesh, a.k.a Hedgehog visualization. Problems: glyphs too small to see (or) glyphs too large and overlap artifacts from mesh misleading for interpretation
6http://cs.swan.ac.uk/~csbob/ Flow Visualization Using Glyphs: Solution New approach: resample vector field onto regular mesh: glyph placement controlled by user user defined grid resolution multiple grids possible interaction: rotation, scaling, and sliding possible
7http://cs.swan.ac.uk/~csbob/ Flow Visualization Using Glyphs: Demo
8http://cs.swan.ac.uk/~csbob/ Flow Visualization Using Streamlines: Seeding Problem Streamline: a curve everywhere tangent to the vector field, very common Challenges: Where should the streamlines be placed? How do we ensure properties of flow are adequately covered? How do we prevent streamlines from clumping together? Regularly spaced seeds do not result in regularly spaced streamlines.
9http://cs.swan.ac.uk/~csbob/ Flow Visualization Using Streamlines: Seeding Solution Evenly-spaced streamlines on surfaces Advantages: Streamlines can be distributed evenly in image space User controls spatial frequency (separating distance) between curves User interaction: zooming, panning supported, fast rendering times
10http://cs.swan.ac.uk/~csbob/ Streamline Seeding on Surfaces: Demo
11http://cs.swan.ac.uk/~csbob/ Summary and Conclusions • Glyph and streamline placement is very difficult for CFD simulation data • We present both glyph and streamline placement strategies for this application • Strategies support full user-interaction and fast rendering speeds • More implementation details can be found in paper.
12http://cs.swan.ac.uk/~csbob/ Acknowledgements • Thank you for your attention! Any questions? We would like to thank the following: • Ben Spencer of Swansea University and the EPSRC for funding this research • PDF versions of papers and MPEG movies available at: http://cs.swan.ac.uk/~csbob