Flow Like You've Never Seen It Robert S. Laramee Visual and Interactive Computing Group Department of Computer Science Swansea University R.S.Laramee@swansea.ac.uk 1

Overview Flow Visualization with a range of techniques: Streamline seeding Stream, path, and streak surfaces Surface placement Texture based flow visualization Feature-based flow visualization Acknowledgments 2

Who is Bob? July 2006: Joined Computer Science Department at Swansea University 2001-2006: worked at VRVis Research Center (VRVis.at)–the bridge between academia and industry in Austria 2005: PhD, Computer Science, Vienna University of Technology (Gruess Gott TUWien) 2000: Msc., Computer Science, University of New Hampshire, Durham, NH 1997: BSc., Physics, University of Massachusetts (ZooMass), Amherst, MA Research in Scientific Visualization, Information Visualization, Visual Analytics 3

Challenge of Flow Visualization Challenge: to effectively visualize both magnitude + direction often simultaneously magnitude only orientation only 4

Automatic Streamline Seeding Videos 5

Stream Surfaces Terminology: Stream surface: a surface that is everywhere tangent to flow Stream surface: the union of stream lines seeded at all points of a curve (the seed curve) Next higher dimensional equivalent to a streamline Unsteady flow can be visualized with a path surface or streak surface 6

Stream Surfaces: Advantages Separates (steady) flow: flow cannot cross surface (stream surfaces only) Perception: Less visual clutter and complexity than many lines/curves Perception: well-defined normal vectors make shading easy, improving depth perception Rendering: surfaces provide more rendering options than lines: e.g., shading and texture-mapping etc. Disadvantages: Construction/Implementation: more complicated algorithms are required to construct integral surfaces Occlusion: multiple surfaces hide one another Placement: placement of surfaces is challenging (video demo) 7

Constructing Streak Surfaces in 3D Unsteady Vector Fields (Video) 88 Constructing Streak Surfaces in 3D Unsteady Vector Fields (Video) Tony McLoughlin, Robert S. Laramee and Eugene Zhang

Stream Surface Placement (Video) 99 Stream Surface Placement (Video) Tony McLoughlin, Robert S. Laramee and Eugene Zhang

Texture-Based Flow Visualization Complete coverage Flow features shown Difficult to apply to 3D Downstream direction shown tumble behavior non-ideal (video) 10

Feature-Based Flow Visualization Feature-Based Visualization Topological skeleton of flow is extracted explicitly Features shown automatically Applicable to 3D Complete coverage Downstream direction not shown (demo video) red = saddle blue = sink green = source 11

Acknowledgements Thank you for your attention! Any questions? We thank the following for their help: Nick Croft, Matthew Edmunds, Christoph Garth Edward Grundy, Helwig Hauser Rami Malki, Ian Masters, Tony McLoughlin, Zhenmin Peng Juergen Schneider, Benjamin Spencer Xavier Tricoche, Daniel Weiskopf, Eugene Zhang This work was partially funded by EPSRC EP/F002335/1 12