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Hi Jef,<br><br>
OK - what you are doing is treating the components are two independent
components, with two separate color/opacity mappings. That is supported
by the vtkFixedPointVolumeRayCastMapper only - so you'll need to use that
mapper. Maybe that is the problem?<br><br>
Lisa<br><br>
<br><br>
At 10:18 AM 6/22/2005, Jef Driesen wrote:<br><br>
<blockquote type=cite class=cite cite="">Maybe mapping components to hue
or value directly is not supported. But what I did was create a different
color transfer function for each component, where only the hue (or value
depending on the component) is changed during the interpolation. And for
the opacity transfer function I used a lineair ramp for both components.
Just like I did in volview (or maybe not?).<br><br>
Maybe it is easier to explain my problem with some pictures. I have
uploaded them to
<a href="http://users.telenet.be/sacn/vtk/">
http://users.telenet.be/sacn/vtk/</a>. The file 'volume-uint16.img' is my
dataset. When I load the file in volview (with the parameters of the
*.vvi and *.vti files), the result is something like the screenshot
'volview.png'. And I want to create a similar result with the vtk
filters.<br><br>
If I render each components separatly with vtk, I can obtain the desired
result. The 'volume-avg.png' and 'volume-std.png' are screenshots of the
renderings of respectively the first and second component of the dataset.
And those result are almost identical to those of volview (created by
setting the component weight to 1.0 and the other one to 0.0). But it
seems inpossible to combine those images, e.g. I get garbage like in the
'volume.png' screenshot.<br><br>
<br>
>From: Lisa Avila <lisa.avila@kitware.com><br>
>To: "Jef Driesen" <jefdriesen@hotmail.com>,
vtkusers@vtk.org<br>
>Subject: Re: [vtkusers] Problem with volume rendering and 2
independent components<br>
>Date: Wed, 22 Jun 2005 09:47:28 -0400<br>
><br>
>Hi Jef,<br>
><br>
>I am not sure how loading the data into VolView is producing
"the <br>
>expected results" - VolView (and therefore the mappers in VTK)
does <br>
>not support mapping the first component to value and the second to
<br>
>hue. What you can do is map the first component to hue (or any hsv
<br>
>or rgb colormap) and the second to opacity. This can be done with
<br>
>the vtkFixedPointVolumeRayCastMapper and the <br>
>vtkVolumeTextureMapper3D. The other volume mappers only support one
<br>
>component data.<br>
><br>
>Lisa<br><br>
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