Virtual-Reality Data Exploration

Contemporary scientific research is performed by gathering and analyzing vast amounts of data. Regardless of whether this data is the result of real-world measurements or numerical simulations, extracting information from data becomes more and more difficult as the amount of data grows. Virtual-reality data exploration is a proposed technique combining real-time visualization, interaction and virtual reality environments to address the growing size and complexity of scientific data.

A virtual-reality data exploration system offers a user the ability to create visualizations of large "live" data sets, i.e., data sets that are transmitted from a running simulation, and to interact with these visualizations to gain better insight into the data. Virtual reality environments offer the benefits of more natural interaction using six-degree-of-freedom input devices, and better understanding of three-dimensional data using stereoscopic output.

Virtual-reality data exploration places several constraints on a framework that require design of specific data structures and algorithms. The most important requirement is the maintenance of high and constant frame rates, to not break the "suspension of disbelief" necessary to interact naturally and effectively with a virtual environment. Most "classic" visualization techniques such as isosurfaces or direct volume rendering were not designed with interactivity in mind; to make those techniques applicable to data exploration they have to be changed or implemented differently. Another requirement is genericity: To be able to deal with live data, a data exploration system cannot afford to perform expensive pre-processing before offering data for exploration; this implies that the data exploration system has to work natively on the provided data, e.g., it is not sufficient to support only a single canonical grid topology and to re-sample source data to that topology.

Figure 1: Exploring a 3D flow data set (resulting from a wind tunnel simulation) by interactively placing and dragging stream ribbons visualizing direction, velocity and vorticity of the flow. The depicted data set is defined on an unstructured (tetrahedral) grid. A video of the program used to visualize seismic tomography data in a CAVE is available for download (MPEG-1 format, 29,273KB).

Project Goals

The main project goals were to design and implement a framework that enables interactive exploration of large three-dimensional scientific data sets defined on different grid structures. This included the following detail goals:

Project Status

The current version of our framework, referred to as 3D Visualizer, supports isosurfaces, streamlines etc. and particle systems on cartesian, rectilinear, (hexahedral) curvilinear, tetrahedral and AMR grids. Our exploration program runs on a multitude of virtual reality hardware, including FakeSpace Immersive Workbench, FakeSpace ImmersaDesk, CAVE and many display wall environments using a virtual reality library developed by ourselves. We presented a paper describing our algorithms and data structures to a workshop on hierarchical methods organized by UC Davis; the paper was later included in a book containing material presented at that workshop. The paper is available for download (PDF version, 603K).

Related Publications

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Screen Shots
Screen shots of data sets visualized using the framework.
Download
Download page for the current and several older releases of 3D Visualizer, released under the GNU General Public License.