Jason J. Corso
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Real-Time Volume Visualization of Unstructured Grids
Collaborators: Joshua Leven, Jonathan Cohen, Subodh Kumar
We developed a method for the voxelization of large scalar fields with
the goal of interactive volume rendering. An adaptive octree is used to
optimally sample the underlying unstructured grid. The unstructured
grid is embedded into a voxel-space and those regions not corresponding
to input data are flagged as being outside of the embedded model. The
octree nodes share borders enabling smooth data continuity between them.
Gradients are computed and stored with the textures for lighting
computation. We integrated this system as a preprocess for an
interactive volume system that we developed. This approach leverages
the current 3D texture mapping PC hardware for the problem of
unstructured grid rendering. We specialize the 3D texture octree to the
task of rendering unstructured grids through a novel pad and stencil
algorithm, which distinguishes between data and non-data voxels. Both
the voxelization and rendering processes efficiently manage large,
out-ofcore datasets. The system manages cache usage in main memory and
texture memory, as well as bandwidths among disk, main memory, and
texture memory. It also manages rendering load to achieve interactivity
at all times. It maximizes a quality metric for a desired level of
interactivity. It has been applied to a number of large data and
produces high quality images at interactive, user-selectable frame rates
using standard PC hardware.
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