Re: strange 3D to 2D behavior

• To: "V. Lakshmanan" <lakshman@xxxxxxxxxxxxx>
• Subject: Re: strange 3D to 2D behavior
• From: Bill Hibbard <billh@xxxxxxxxxxxxx>
• Date: Sat, 24 Aug 2002 09:05:48 -0500 (CDT)

Hi Lak,

First, do not call clearMaps() and then add all the ScalarMaps
every time you add new Data to the Display. Instead, make all
your addMap() calls once at the begining, then to add new Data
just call addReference().

Second, I suspect that your cones are becomming flat because
they are at different ranges of Z values. When there is just
one cone, the autoscaling for Z values does a setRange() for
the Z ScalarMap that just covers the small range of Z values
of that one cone. But the second cone may be at a very different
range of Z values, so the autoscaling algorithm sets a much
greater range of Z values to cover both cones and they become
very flat.

I see your application enables axis scales. Check whether
you are getting a much greater range of Z values with multiple
calls.

Good luck,
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


On Fri, 23 Aug 2002, V. Lakshmanan wrote:

>
> I get strange behaviour when I try to add two
> cones to the display.
> The first cone shows up just fine, but when
> the second cone is added, the display
> shows the two cones parallel to the xy plane.
> (This is with Bill's texture mapping fix;
> With the release version of visad.jar, I get
> an OutOfMemoryError)
>
> http://www.nssl.noaa.gov/~lakshman/visad/3d_to_2d.html
>
> The problem is probably in the way I am adding
> the ElevationScans to the display (I'm clearing
> out the data references, then re-adding them):
>
>         display.removeAllReferences();
>         display.clearMaps();
>         display.addMap( new ScalarMap( dr.x, Display.XAxis ) );
>         display.addMap( new ScalarMap( dr.y, Display.YAxis ) );
>         display.addMap( new ScalarMap( dr.z, Display.ZAxis ) );
>
>         for each drawable:
>         {
>             ScalarMap dataMap = new ScalarMap( gatevalue,
> Display.RGBA );
>         dataMap.setRange( myColorFunction.min, myColorFunction.max );
>         display.addMap( dataMap );
>
>         // change the colormap from the default ...
>         ColorAlphaControl color = (ColorAlphaControl)
> dataMap.getControl();
>         color.setTable( myColorFunction.colorTable );
>         }
>
>
>         for each drawable{
>             display.addReference( data );
>         }
>
>
> Is there a better way? Is what I am doing wrong?
>
> thanks
> Lak
>
>

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