%0 Journal Article %J Visualization and Computer Graphics, IEEE Transactions on %D 2004 %T Selective refinement queries for volume visualization of unstructured tetrahedral meshes %A Cignoni,P. %A De Floriani, Leila %A Magillo,P. %A Puppo,E. %A Scopigno,R. %K Automated;Signal Processing %K Computer-Assisted;Imaging %K Computer-Assisted;User-Computer Interface; %K data structure;geometric modeling;interactive visualization;large data sets;multiresolution model;selective refinement queries;unstructured tetrahedral meshes;variable resolution queries;volume data visualization;data visualisation;mesh generation;query p %K Three-Dimensional;Online Systems;Pattern Recognition %X We address the problem of the efficient visualization of large irregular volume data sets by exploiting a multiresolution model based on tetrahedral meshes. Multiresolution models, also called Level-Of-Detail (LOD) models, allow encoding the whole data set at a virtually continuous range of different resolutions. We have identified a set of queries for extracting meshes at variable resolution from a multiresolution model, based on field values, domain location, or opacity of the transfer function. Such queries allow trading off between resolution and speed in visualization. We define a new compact data structure for encoding a multiresolution tetrahedral mesh built through edge collapses to support selective refinement efficiently and show that such a structure has a storage cost from 3 to 5.5 times lower than standard data structures used for tetrahedral meshes. The data structures and variable resolution queries have been implemented together with state-of-the art visualization techniques in a system for the interactive visualization of three-dimensional scalar fields defined on tetrahedral meshes. Experimental results show that selective refinement queries can support interactive visualization of large data sets. %B Visualization and Computer Graphics, IEEE Transactions on %V 10 %P 29 - 45 %8 2004/// %@ 1077-2626 %G eng %N 1 %R 10.1109/TVCG.2004.1260756