A Novel Information-Aware Octree for the Visualization of Large Scale Time-Varying Data

TitleA Novel Information-Aware Octree for the Visualization of Large Scale Time-Varying Data
Publication TypeReports
Year of Publication2006
AuthorsKim J, JaJa JF
Date Published2006/04/20/T16:3
InstitutionInstititue for Advanced Computer Studies, Univ of Maryland, College Park
KeywordsTechnical Report

Large scale scientific simulations are increasingly generatingvery large data sets that present substantial challenges to
current visualization systems. In this paper, we develop a new
scalable and efficient scheme for the visual exploration of 4-D
isosurfaces of time varying data by rendering the 3-D isosurfaces
obtained through an arbitrary axis-parallel hyperplane cut. The
new scheme is based on: (i) a new 4-D hierarchical indexing
structure, called Information-Aware Octree; (ii) a
controllable delayed fetching technique; and (iii) an optimized
data layout. Together, these techniques enable efficient and
scalable out-of-core visualization of large scale time varying
data sets. We introduce an entropy-based dimension integration
technique by which the relative resolutions of the spatial and
temporal dimensions are established, and use this information to
design a compact size 4-D hierarchical indexing structure. We also
present scalable and efficient techniques for out-of-core
rendering. Compared with previous algorithms for constructing 4-D
isosurfaces, our scheme is substantially faster and requires much
less memory. Compared to the Temporal Branch-On-Need octree
(T-BON), which can only handle a subset of our queries, our
indexing structure is an order of magnitude smaller and is at
least as effective in dealing with the queries that the T-BON can
handle. We have tested our scheme on two large time-varying data
sets and obtained very good performance for a wide range of
isosurface extraction queries using an order of magnitude smaller
indexing structures than previous techniques. In particular, we
can generate isosurfaces at intermediate time steps very quickly.