Re: volume rendering, scale

Brad,

>Date: Mon, 15 Nov 1999 00:16:07 -0800
>From: "Brad Buchsbaum" <bbuchsba@xxxxxxx>
>To: <visad-list@xxxxxxxxxxxxx>
>Subject: volume rendering, scale
>Keywords: 200011150824.eAF8Ofo06491

The above message contained the following:

> I just started with VisAd and am trying to display a volume rendered
> image.  I have a stack of 16 images with dimensions (64,64,16) and
> voxel dimensions of (4,4,6).  So I create a Linear3DSet like so:
> 
> Linear3Dset set new Linear3DSet(tuple3d, 0, 256, 64,
>                                          0, 256, 64,
>                                          0, 96, 16);
> 
> However, the rendered image is not properly scaled in the z-plane.
> The range of the z axis goes from 1 to 96, as expected, but the actual
> image only takes up about 1/5 of that area.  So what I get is a very
> smushed looking object (brain) in one dimension.

Sounds like you didn't expand (i.e. replicate) your voxels in the Z
dimension.

I would think that a better approach would be to not attempt to
copy data values to produce voxels, but rather to let VisAD "do its
thing" (it will interpolate data values as necessary to "fill in" the
display).

Assuming you're using a FlatField, then its domain would be something
like the following:

    new Integer3DSet(64,64,16)

Regards,
Steve Emmerson   <http://www.unidata.ucar.edu>