Kolloquiumszyklus - previous dates

Dieser Vortrag muss leider abgesagt werden, da Prof. Bartz am 28.3.2010 verstorben ist!

A rapidly growing computer graphics community has contributed to dramatic increase in complexity with respect to geometry as well as physical phenomena. Simulating, approximating and visualizing geometry consisting of tens of millions of polygons simultaneously tested for collision or visibility is becoming increasingly common. Further, recent technological innovations from graphics card vendors have given impetus to achieving these results at very high frame rates. Despite tremendous developments in graphics hardware, capturing the complete surrounding environment poses a significant challenge. Given the added time constraint for real-time or interactive rates, simplified representations and suitable approximationsof physical effects are of key importance.
This talk will focus on simplified representations and computations to achieve real-time performance for complex tasks and concentrates on a variety of topics including simplification, visibility, soft shadows and voxelization.

The talk will be about the physiology of plants and how to implement branching, tropisms, hormons and their control in simplifyfied simulations. Also, generation for real time models including metric, LODs, textures, streaming as well as rendering and lighting will be covered in the talk.

Numerical flow visualization is gaining importance because of the continuing trend from experiments toward computational fluid dynamics. We have come to the situation where reliable numerical data are easily available but often hard to interpret because their size and intricacy challenge current visualization tools. The state of the art in flow visualization is advancing on several fronts, an important one being the field of feature-based visualization, which aims at revealing flow features such as vortices, flow separation, or recirculation. Such flow phenomena are of interest because of their effect, either beneficial or adverse, in industrial applications like power generation, mixing, or combustion. Feature-based flow visualization again splits into several branches, but one of them has become particularly popular under the name of vector field topology.

In this talk we present work in topology-based flow visualization, resulting from our collaboration with turbomachinery companies and focusing on the optimization of water turbines. We discuss the usage of vector field topology for extracting the above mentioned flow features, and additional ones such as vortex rings and vortex breakdown bubbles. We address the limitations of vector field topology and the current search for an adequate extension to unsteady flow fields. Finally we move to the field of Lagrangian coherent structures, which can be interpreted as a time-dependent variant of vector field topology. There, we present a technique for accelerating their computation, based on adaptive mesh refinement.