[vtkusers] vtkImageCast Extent-problem

[Benjamin King]

Hi Florian,

your problem is caused by the vtkVolumeMapper class. It uses a vtkImageClip 
object whose extent isn't reset correctly when the input changes. There is 
a new method vtkVolumeMapper::SetUseImageClipper that looks promising. I 
didn't test it, but you can try to switch the vtkImageClip off.
If this doesn't work, there is some code in vtkVolumeMapper::SetInput that 
resets the extent of the vtkImageClip which has been commented out. You can 
try to put that back in.


Hope it helps,
  Benjamin


On Wed, 20 Aug 2003 18:29:14 +0200, Florian Schmidt <mista.tapas at gmx.net> 
wrote:

>
> Hi,
>
> i have a volume rendering pipeline which is very basic and the first step 
> in it is a vtkImageCast to get the data into unsigned short format. Now 
> here's the problem:
>
> The first vtkImageData which is fed into the pipeline is rendered 
> correctly, but when i lateron change the input of the vtkImageCast to a 
> new vtkImageData [with a different Extent], somehow only the old extent 
> is rendered.
>
> Here's some more details: First i setup the rendering pipeline with some 
> dummy data which is vtkImageData with an extent like 0,32,0,32,0,32. 
> Lateron upon user interaction i want to render a volume of extent 
> 0,256,0,128,0,64, but only the part of this imagedata which fits into the 
> 0,32,0,32,0,32 extent is rendered.. what am i doing wrong? Can i somehow 
> tell the pipeline to propagate the changed extent from the start to the 
> end?
>
> If you need more details or example code, let me know..
>
> T.I.A. Florian Schmidt
>
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-- 
Benjamin King
Institut für Medizinische Informatik
Medizinische Hochschule Hannover
Tel.: +49  511  532-2663