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Fast Probing for Irregular Volumes

IP.com Disclosure Number: IPCOM000110138D
Original Publication Date: 1992-Oct-01
Included in the Prior Art Database: 2005-Mar-25
Document File: 3 page(s) / 82K

Publishing Venue

IBM

Related People

Koyamada, K: AUTHOR

Abstract

Disclosed is a fast probing technique for irregular volumes. A volume means a dataset where scalar data are defined at nodes of volume cells. In an irregular volume, the position of the nodes and the topology of the cells can be irregular. This technique assumes that all irregular volume cells are subdivided into tetrahedral cells (1) and managed under a tetrahedral model (2).

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Fast Probing for Irregular Volumes

       Disclosed is a fast probing technique for irregular
volumes.  A volume means a dataset where scalar data are defined at
nodes of volume cells.  In an irregular volume, the position of the
nodes and the topology of the cells can be irregular.  This technique
assumes that all irregular volume cells are subdivided into
tetrahedral cells (1) and managed under a tetrahedral model (2).

      Probing is a technique for visualizing data at an arbitrary
point (a seed point).  The proposed technique traverses tetrahedral
cells toward the seed point, assuming some constant velocity vector.
Two algorithms are included in the technique according to the
following ways in which a seed point is specified:
 1. By moving from a point in a tetrahedral cell.
 2. By giving the coordinates of the seed point.

      For the first specification, the technique (probel) assumes
that a user gives a translation vector (u) from a current position
(p) that is included in a cell (see Fig. 1).  Probel finds the seed
cell by traversing cells with a velocity (u).  In the traverse of
cells along the line, if t-entry and t-exit, which are the times
required for the traversing edge to reach an entry point and an exit
point in a cell, satisfy:
  t-entry < 1.0 < t-exit,
then the seed point is included in the cell.  If the above inequality
is satisfied for no cell along the line, the seed point is not
included in any cell along the line and the tra...