Hi Stuart,
My guess is that you are seeing a manifestation of the Java3D
transparency depth-sorting problem that has been around for
many versions.
You can see the bug by running Test20 of the VisAD examples
and setting part of the 2-D surface to be transparent using
the color widget. If you rotate the surface around, looking
through the transparent area, and you should notice behavior
like you describe from some angles.
Unfortunately, I know of little you can do to correct this
problem, except for waiting until a version of Java3D comes
out that corrects it (supposedly, Java3D v1.3 will fix it).
According to Sun, it is a difficult issue.
-Curtis
At 16:24 7/13/01, you wrote:
>Transparency is working in 3d idossurfaces by making a
>ScalarMap to Display.RGBA and providing a color-alpha table
>of the form float [4][length], with the last element being alpha.
>Resetting the color table with a new value of alpha changes
>the transparency as expected.
>
>The surface is transparent to the VisAD wireframe box,
>some lines in black (contours of other data for example),
>and to other isosurfaces. It's cool seeing one isosurface
>inside another one.
>
>However the surface is always opaque to map background lines
>and pseudo-colored data surfaces on a level under the 3D surface.
>For these objects the isosurface at full transparency verges
>to an opaque VisAD background color, black for example (unless
>the background color is changed from black).
>
>Anyone one have any idea what is going on?
>
>Stu
>--
>
>Stuart Wier UCAR Unidata Program
>wier@xxxxxxxxxxxxxxxx P.O. Box 3000
>http://www.unidata.ucar.edu/staff/wier Boulder, CO 80307
