CashFlow, A Visualization Framework for 3D Flow - Studierstube ...

Related Work2.2. Flow Visualization Algorithmsof the flow. Behind that stream ribbons an arrow plot, which is bound to a stream line,emphasize the change of direction. In the back simple stream lines point out theincreasing density of the flow towards the roof. Finally the color map generated fromthe scalar value total energy is applied to the cutting plane in the back. The hull of thecar is an iso–surface, where velocity magnitude is equal zero. This image proves, thata combination of simple visualization techniques results in an image easy to perceive.Classification of Visualization AlgorithmsThese algorithms can be grouped by their complexity:• Low complexityThese simple algorithms do not generate intermediate data but render directly.– Basic techniques– Glyph, Arrows and Hedgehogs– Color mapping onto surfaces• Medium complexityThis group of algorithms generate intermediate data, which can be used by otheralgorithms also. Best examples are stream lines and iso–contours. These techniqueshave medium complexity.– Particle Trace– Contour Lines and Surfaces– Texture Advection– Volume Rendering• High complexityThese algorithms are based on results from medium complexity techniques.These techniques have high complexity.– Flow Field Topology– Interactive Data Generation– Streamline Seed point Strategies2.2.1 Basic Techniques• Glyphs, Arrows and HedgehogsUsing arrows or hedgehog’s to show the direction and the magnitude of the flowis an old concept. The extension to that is the use of glyphs. Glyphs do not onlyshow the direction and magnitude of the flow, but they also could be bound toother attributes. Figure 2.19b) on page 23 shows a Glyph visualization of a tornado.This visualization is very intuitive as long as each arrow can be perceived20