Re: Volume rendering of Irregular3DSet

• To: Bill Hibbard <hibbard@xxxxxxxxxxxxxxxxx>
• Subject: Re: Volume rendering of Irregular3DSet
• From: Robert S Laramee <rlaramee@xxxxxxxxxxxxxxx>
• Date: Fri, 23 Mar 2001 14:30:00 -0500 (EST)

> The problem with trasnparency is that it only works right when
> the polygons are sorted in back to front order, but the sort
> order depends on how the user rotates the view. The Java3D
> team has plans to add dynamic sorting, but its a very hard
> problem and won't appear in Java3D for a while.
>
> This same sorting problem is the reason the volume rendering
> needs six rather than three different sets of planes. But the
> sort is more complex for iso-surfaces because they are irregular.
>
> You might be able to do something with:
>
>   display.getGraphicsModeControl.setTransparencyMode(
>      javax.media.j3d.TransparencyAttributes.SCREEN_DOOR);
>
> It didn't work in an early Java3D implementation, but I
> haven't tried it recently. Screen door transparency
> avoids the sorting problems (we use it in Vis5D). Let me
> know what success you have - I'll help if I can.

Thanks for the suggestion.  Unfortunately, it looks as if the method call
above turns the transpareny off completely (at least with the version of
Java 3D we're using).  But we are using Java 3D on Red Hat Linux, which
may be a little bit behind the versions for Sun and that other OS.

-cheers, bob

Robert S Laramee        tel:    (603) 868-1361
9 Woodman Road, #314    office: (603) 862-4336
Durham, NH 03824        URL:   http://www.cs.unh.edu/~rlaramee

• References:
  • Re: Volume rendering of Irregular3DSet
    • From: Bill Hibbard