Re: Volume Rendering Technique in VisAD

• To: #TAN TOH FEI# <PA10198510@xxxxxxxxxx>
• Subject: Re: Volume Rendering Technique in VisAD
• From: Bill Hibbard <hibbard@xxxxxxxxxxxxxxxxx>
• Date: Wed, 09 May 2001 07:31:50 -0500

Hi TAN TOH FEI,

> I'm just wondering what sort of technique is being used for Volume Rendering
> in VisAD. Is it "Splatting", "Spatial Technique", "Blending" or something
> else? Hopefully someone can answer my doubt. By the way, may I know which
> particular file(s) in VisAD package is attached with this Volume Rendering
> code. Thanks n Cheers.

The technique is to render a cartesian grid as a series of
transparent planes, aligned to the axes most nearly
perpendicular to the view direction (so the planes change
as you rotate in 3-D).

This technique was first described by my 1989 paper with
Dave Santek:

  Hibbard, W., and D. Santek, 1989; Interactivity is the key.  Chapel Hill
  Workshop on Volume Visualization, University of North Carolina, Chapel Hill,
  39-43.

The technique is now widely used, since it exploits graphics
hardware for fast volume rendering.

The code for implementing it in VisAD is in
visad/ShadowFunctionOrSetType.java (look for code inside
"if (isTexture3D) { ... }") and in
visad/java3d/ShadowFunctionOrSetTypeJ3D.java in the
textureStackToGroup() method.

This technique is also used for the volume rendering demos
distributed with Java3D.

Cheers,
Bill
----------------------------------------------------------
Bill Hibbard, SSEC, 1225 W. Dayton St., Madison, WI  53706
hibbard@xxxxxxxxxxxxxxxxx  608-263-4427  fax: 608-263-6738
http://www.ssec.wisc.edu/~billh/vis.html

• References:
  • Volume Rendering Technique in VisAD
    • From: #TAN TOH FEI#