Design and Implementation of Geometric and Texture-Based Flow Visualization Techniques Robert S. Laramee Markus Hadwiger Helwig Hauser VRVis Research Center Vienna, Austria

2Design and Implementation of Geometric and Texture-Based Flow Visualization Techniques introduction: CFD and our goals classification: direct, geometric, texture-based flow visualization system requirements and goals visualization system design subsystem design and implementation the geometric flow visualization sub-system the texture-based flow visualization sub- system discussion and evaluation summary, conclusions, acknowledgements, questions (+ answers)

3Design and Implementation of Geometric and Texture-Based Flow Visualization Techniques Introduction, The CFD Process all research work was carried out within a commercial system for visualization of computational fluid dynamics (CFD) simulation data goal: convey consequences of research prototype within industry level system, i.e., strategies used, advantages and disadvantages

4Design and Implementation of Geometric and Texture-Based Flow Visualization Techniques Flow Visualization Classification 1. direct: overview of vector field, minimal computation, e.g. glyphs, color map 2. texture-based: complete coverage, more computation time, implementation time, e.g., Spot Noise, LIC 3. geometric: compute a discrete object whose geometry reflects flow characteristics, e.g. streamlines

5Design and Implementation of Geometric and Texture-Based Flow Visualization Techniques System Requirements and Goals interactivity platform independence support for a wide range of simulation data sets support for versatile CFD grids tools that address perceptual challenges of 3D flow visualization

6Design and Implementation of Geometric and Texture-Based Flow Visualization Techniques Visualization System Design

7Design and Implementation of Geometric and Texture-Based Flow Visualization Techniques geometric techniques are especially applicable to 3D flow a geometry is computed that reflects the properties of the flow example: a streamline-a line that is everywhere tangent to the flow seeding is a problem one approach: interactive seeding plane Geometric Flow Visualization

8Design and Implementation of Geometric and Texture-Based Flow Visualization Techniques The Geometric Flow Visualization Subsystem The Process the processing pipeline several interchangeable components interactive seeding (requirement)

9Design and Implementation of Geometric and Texture-Based Flow Visualization Techniques The Geometric Flow Visualization Subsystem The Design a class hierarchy of rendering options children inherit features of parents facilitates extensions object-oriented methodology affords developers independence

10Design and Implementation of Geometric and Texture-Based Flow Visualization Techniques problem with geometric approaches: do not provide complete coverage of vector field texture-based approaches do a texture is computed that reflects the properties of the flow problems with previous texture-based approaches: computation time limited to 2D Texture-Based Flow Visualization

11Design and Implementation of Geometric and Texture-Based Flow Visualization Techniques The Texture-Based Flow Visualization Subsystem The Process fast frame rates (requirement) effective use of graphics hardware still platform independent (requirement)

12Design and Implementation of Geometric and Texture-Based Flow Visualization Techniques The Texture-Based Flow Visualization Subsystem The design composition relationships are shown e.g. Textures are- part-of a Texture Stack design process essential for large, stable, and robust software

13Design and Implementation of Geometric and Texture-Based Flow Visualization Techniques Discussion and Evaluation Advantages of a big commercial system: facilitates combinations of options some engineering already implemented more user feedback interdisciplinary can generate revenue

14Design and Implementation of Geometric and Texture-Based Flow Visualization Techniques Discussion and Evaluation Disadvantages of a big system: steep learning curve, 1000s of files complexity longer compilation time longer testing time many user requests

15Design and Implementation of Geometric and Texture-Based Flow Visualization Techniques We achieved interactivity through design choices and intelligent algorithms platform independence realized by using platform independent libraries, e.g. FOX and OpenGL 1.1. versatility achieved through thorough many user options and testing, i.e., many users, many data sets tools that address perceptual challenges in 3D: key interactivity and user options

16Design and Implementation of Geometric and Texture-Based Flow Visualization Techniques We presented how we incorporated research work into an industry grade software project. incorporating research software into a commercial system is possible (but not easy) many advantages and disadvantages more requirements than research prototypes alone intelligent design choices required object-oriented methodology-very helpful if not essential

17Design and Implementation of Geometric and Texture-Based Flow Visualization Techniques Thank you for your attention! Questions? This work was supported by the Austrian national program Kplus (kplus.at) and AVL (avl.com). CFD simulation data courtesy of AVL. For more information, please visit:

18Design and Implementation of Geometric and Texture-Based Flow Visualization Techniques What about Feature-Extraction/Detection? Thank you for the excellent question! See: