Hi,
> On Wed, 2005-01-05 at 04:44, Manfred Weiler wrote:
> > > Now I need to read back the plane where the volume is cut as a 2d
> > > texture. What I gathered so far is that the ClipPlaneChunk is not the
> > > way to go, but I haven't been able to find any documentation about this
> > > in OpenSG/Source/System/NodeCores/Drawables/VolRen.
> >
> > Unfortunately the volume node does not support such slice extraction
> > from the volume data so far. Of course you could just reduce the slice
> > number (or sampling distance) so that only one slice plane is drawn, but
> > this would not be at the position you like to have. So depending on your
> > actual task and your will to perform modifications to OpenSG itself
> > I see different solutions:
> >
> > 1. You could use two clip planes with a distance sufficient for exactly
> > one slice plane. By cutting away also the back of the volume you
> > would thereby create a single cut slice of the volume.
>
> This sounds like the simplest solution. I'm just not sure if that gives
> Allan enough control, as it doesn't really extract only a single slice.
Well, of course it depends on the circumstances. But with tweaking a little
bit with the clip planes it is possible to render only one slice. And
blending only one slice on a black background is equivalent with rendering
the slice with the volume texture mapped onto the slice with replace texture
environment.
>
> > 2. You could use a 3D-Texture of your own and render a single slice inside
> > this volume with the texture mapped on that slice. This would have the
> > advantage that your slice could have any orientation with respect to
> > the volume or the view direction. Unfortunately this would require to
> > compute intersection of the cutting plane with the bounding box of
> > the volume yourself.
What I meant was the following: Compute the desired slice polygon yourself.
Which essentially requires the reimplementation of the slicing code in
DVRVolume. Define it as a Geometry. And use a simple 3D-Texture-Material
to render the Geometry. This would probably be the most efficient solution.
But I agree that the effort would be quite similar to extending the DVRVolume.
Manfred.
======================================================================
Manfred Weiler [EMAIL PROTECTED]
Visualisierung und Interaktive Systeme Telefon: 0711/7816-208
Universitaet Stuttgart, IfI FAX: 0711/7816-340
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