The type conversion happens because if you cut an arbitrary shape out of a structured dataset the result is necessarily unstructured, unless the arbitrary shape happens to be very regular like ExtractVOI's is.<br><br>vtkExtractSelectedFrustum can add cell and point data arrays called "vtkInsidedness" so as to preserve the type of the data while performing an extraction. In your downstream filters you could use that to do what you want. For example you could use that array to make the opacity
0.0 outside the region of interest in the transfer function.<br> <br>That being said I don't know if there are any other filters that create that array.<br><br>hth,<br>Dave DeMarle<br><br><br><div><span class="gmail_quote">
On 3/2/07, <b class="gmail_sendername">Michael Knopke</b> <<a href="mailto:Michael.Knopke@gmx.de">Michael.Knopke@gmx.de</a>> wrote:</span><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
Hi,<br><br>while I'm aware of class vtkExtractVOI, this is not what I want to achieve.<br>vtkExtractVOI will let me extract only a box of interesst. I want to cut out<br>any arbitrary shape (spline), so it's probably best to use an implicit
<br>function. There are several classes that work with implicit functions but<br>always return unstructured grid. To still use the volumedata I need it to be<br>vtkImageData. Can anybody help.<br><br>I want to be able to extract only a part of my volume and visualize it with
<br>raycast or cut out unwanted parts that overlap the view.<br><br>Thanks<br><br>Michael<br>--<br>Ist Ihr Browser Vista-kompatibel? Jetzt die neuesten<br>Browser-Versionen downloaden: <a href="http://www.gmx.net/de/go/browser">
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