Re: Linear3DSet

• To: marcel-sl@xxxxxx
• Subject: Re: Linear3DSet
• From: Bill Hibbard <billh@xxxxxxxxxxxxx>
• Date: Sun, 30 Mar 2003 15:17:03 -0600 (CST)

Hi Marcel,

> > http://www.ssec.wisc.edu/~billh/tutorial/s4/P4_10.java

First, you are using an old version of Ugo's tutorial. Please
use the version at:

  http://www.geogr.uni-jena.de/~p6taug/visad/tutorial/index.html

The slow performance you are seeing for P4_10.java in the
tutorial is inherent in volume rendering. The 100 x 100 x 100
volume you want apply it to has 1,000,000 volume points. For
this will need the fastest 3-D graphics card, which is probably
nVidea's fastest (whatever that currently is).

> By adding the line
> dispGMC.setTextureEnable(false);
> the program is extremely more performant than without this line.
> Unfortunately now the smoother doesn't work any more and many small cubes
> appear which make the whole plot not very nice. Can I remove these small
> cubes and tell the smoother to work, without making the program
> unperformant again ?

The setTextureEnable(false) causes the volume to be rendered as
individual points, which is faster than volume rendering.

The only good alternative is to use a technique that doesn't show
the whole volume at once, such as an interactive iso-surface (let
the user interactively select the iso-level using a ContourWidget),
or an interactive plane slice. That would be the 3-D analog of the
Python example at:

  http://www.ssec.wisc.edu/~tomw/visadtutor/t7example.html

You could plot a Real along a vertical axis using
DirectManipulationRendererJ3D, triggering a CellImpl that
constructs a Gridded3DSet with manifold dimension = 2 at the
height of the Real and resamples your 3-D volume Field to
that Set, then passes the result to the setData() method of
a DataReference linked to the display.

Good luck,
Bill

• Follow-Ups:
  • Re[2]: Linear3DSet
    • From: Marcel Schmittfull

• References:
  • Re: Linear3DSet
    • From: marcel-sl