<br><font size=2 face="sans-serif">Thomas,</font>
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<br><font size=2 face="sans-serif">Something doesn't sound right here.....you should have 27 voxels wth 27 associated scalars. When rendered, this should give you 27 voxels. I would not expect 8 voxels. Are you sure your image data is really 3x3x3? Perhaps sharing your short code would be helpful....john</font>
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<br><font size=2 face="sans-serif">p.s Interpolation is for sampling scalars during rendering if I remember correctly....has nothing to do with interpolating to get more voxels</font>
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<td><font size=1 face="sans-serif"><b>Thomas Faust <tf@thermoanalytics.com></b></font>
<br><font size=1 face="sans-serif">Sent by: vtkusers-admin@vtk.org</font>
<p><font size=1 face="sans-serif">05/06/2004 06:28 PM</font>
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<br><font size=1 face="sans-serif"> To: David Gobbi <dgobbi@imaging.robarts.ca></font>
<br><font size=1 face="sans-serif"> cc: vtkusers@vtk.org, (bcc: John Anast-JM/PGI)</font>
<br><font size=1 face="sans-serif"> Subject: Re: [vtkusers] voxel values in vtkImageData</font></table>
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Thanks David, but this doesn't solve my problem at all.<br>
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I was changing the interpolation method back and for, but the output didn't <br>
changed.<br>
<br>
I'm not dealing with values that are defined on the gridpoints; my values are <br>
the voxel itself. <br>
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I'll give you (David and all out there) an example:<br>
My matrix is 3x3x3 with the values: 000 010 000 - 010 111 010 - 000 010 000<br>
Do I expect to much brain grease if i would ask you to picture this values in <br>
your imagination in 3D? Right, this is an 3D cross.<br>
But, if this is my vtkImageData I'll get a volume, that is just 2 voxels in <br>
each direction. Please give it a try. (I'll at the 15 line source code if you <br>
want me to)<br>
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What I'd like to see as an output is an volume, that comes with 27 (3x3x3) <br>
voxel. This means that this volume would have 64 (4x4x4) gridpoints. What I <br>
told about interpolation is, that i can't interpolate these 64 gridpoints out <br>
of the 27 values to create my own new vtkImageData.<br>
It's all about the interpretation of values in vtkImageData by <br>
vtkVolumeMapper.<br>
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Thanks for your efforts.<br>
Thomas<br>
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On Thursday 06 May 2004 05:56 pm, you wrote:<br>
> Hi Thomas,<br>
><br>
> It looks like all you need to do is turn off interpolation:<br>
><br>
> volume->GetProperty()->SetInterpolationTypeToNearest();<br>
><br>
> On Thu, 6 May 2004, Thomas Faust wrote:<br>
> > Hi VTK users,<br>
> ><br>
> > Lately I'm confronted with volume rendering. I decided to use VTK as<br>
> > graphical tool to render a huge mass of data. So far, I'm impressed by<br>
> > the power and usability of VTK.<br>
> ><br>
> > My problem is the handling of vtkImageData in vtkVolumeMapper.<br>
> > My model is created by a collection of values in 3 directions (x,y,z).<br>
> > These are stored in vtkImageData.<br>
> > I expect a volume that extent 3 values(voxels) in each direction to be 3<br>
> > length units long. But it isn't (It's just 2). The reason for this is,<br>
> > that the vtkVolumeMapper interprets 3 points in one direction as 3 corner<br>
> > points (vertices) of voxels. So I end up with 2 voxels that are a mixture<br>
> > between my original values.<br>
> ><br>
> > The problem is that a interpolation between these values is not a option,</font>
<br><font size=2 face="Courier New">> > because two values that are even close together means totaly different<br>
> > things. (e.g. 0x40 is material A, 0x41 is material B)<br>
> ><br>
> > How can I change one of the vtkVolumeMappers to interpret the values in<br>
> > vtkImageData to be voxel-based and not vertex-based?<br>
> ><br>
> > Any comments are welcome and will be answered.<br>
> > Thanks in advance<br>
> > _______________________________________________<br>
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