Interactive visualization of particle systems

The interest in particle methods and gridless discretizations has been increasing enormously in recent times: a development which is especially boosted by the rapid progress of hardware capabilities and the design of new highly sophisticated algorithms, thanks to which nowadays systems of several millions degrees of freedom can be simulated. Consequently there is a high demand for interactive visualization tools to explore the huge amount of data. Several techniques for visualizing particle systems are presented. These methods are based on efficient algorithms and models and make frequent use of the texture mapping capabilities of modern graphics hardware to improve the efficiency of scene display and, for example, to display properly illuminated particle traces. The main stress of the discussion is put on the presentation of a multiresolutional concept that enables the visualization of systems which even consist of several millions of particles. Its basic idea is to display a density function instead of resolving regions of high particle density particlewise. Therefore we construct two adaptive hierarchical trees, one of which is to store the particle information, whereas the other one contains complete density information. For the sake of economical memory management, both trees are efficiently stored in hash tables.