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<TITLE>Re: [Paraview] How to do volume rendering of image data?</TITLE>
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<FONT FACE="Calibri, Verdana, Helvetica, Arial"><SPAN STYLE='font-size:11pt'>The data you sent has RGB values but no alpha values that I can see. Volume rendering is generally not very useful if you do not have some representation of opacity. If you were to assume a homogeneous opacity, you would get a mostly black box with a blob of color in the middle if you looked hard enough. How exactly you expect the volume renderer to behave?<BR>
<BR>
-Ken<BR>
<BR>
<BR>
On 7/18/10 2:43 AM, "Steve Huntley" <<a href="stephen@xhuntley.net">stephen@xhuntley.net</a>> wrote:<BR>
<BR>
</SPAN></FONT><BLOCKQUOTE><FONT FACE="Calibri, Verdana, Helvetica, Arial"><SPAN STYLE='font-size:11pt'>Attached is a small sample vtk file that illustrates the problem. It is<BR>
a rough representation of a human molar composed originally of 13 jpeg<BR>
image slices, processed into a raw file with ImageJ, then saved to vtk<BR>
by Paraview.<BR>
<BR>
When I open the file in Paraview 3.2 I see a black block when I choose<BR>
volume representation. The information tab describes it as a uniform<BR>
rectilinear grid and shows number of points and cells, just like the<BR>
info tab of the sample wavelet object described by Utkarsh does.<BR>
<BR>
When I open it in Paraview 3.8, the statistics entries in the<BR>
information tab are blank, and when I try to choose volume<BR>
representation I get the error mentioned below.<BR>
<BR>
Utkarsh, I'm not sure what you mean by "single component point scalars."<BR>
Does this mean that color images with three scalar RGB values per grid<BR>
node can't be volume rendered? If so, does that mean that what I'm<BR>
currently attempting is impossible in Paraview? Or is there a way to<BR>
hack RGB color information into single-value scalars and render a color<BR>
3D image?<BR>
<BR>
Moreland, Kenneth wrote:<BR>
> Nope. ParaView is just telling you that the current operation is not<BR>
> supported.<BR>
><BR>
> Probably the best course of action is to submit a feature request to<BR>
> ParaView’s bug list (<a href="http://www.paraview.org/Bug">http://www.paraview.org/Bug</a>) to which you can<BR>
> attach an example file. I would also recommend entering the feature in<BR>
> uservoice (<a href="http://paraview.uservoice.com/forums/11350-general">http://paraview.uservoice.com/forums/11350-general</a>). The<BR>
> ParaView developers use this site to determine the priority of<BR>
> suggested features.<BR>
><BR>
> If you have an example data set that is not too big, you can email it<BR>
> to the mailing list or directly to me and I can do these for you.<BR>
><BR>
> -Ken<BR>
><BR>
><BR>
> On 7/17/10 2:38 AM, "Steve Huntley" <<a href="stephen@xhuntley.net">stephen@xhuntley.net</a>> wrote:<BR>
><BR>
> Up to now I have been working with version 3.2. I just installed<BR>
> version 3.8 to see if there were any differences in behavior.<BR>
><BR>
> In version 3.8 I'm not allowed to do volume rendering at all. When I<BR>
> try to set the "Volume" representation option (which resulted in<BR>
> display<BR>
> of a black block in 3.2), I now get an error message that says "Cannot<BR>
> volume render since no point (or cell) data available."<BR>
><BR>
<BR>
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