Slow March

[Charles Law]

<x-flowed>Sathya,

There are a couple of things you could do to keep from thrashing.


At 08:31 AM 9/2/99 -0500, Sathya Krishnamurthy wrote:
>Hello All
>
>I've been trying to visualize CT data for past few weeks.
>... The program consumed all the
>memory and began to crawl..rather not respond, though the initial rendering
>took place.
>
>Also for a pipeline which goes like
>
>vtkBMPReader
>vtkImageConstantPad
>vtkContourFilter
>...
>
>Can somebody tell me for which of these items I can use early delete of the
>objects with out affecting my output ?

VTK will do this for you. If you call the method

reader->GetOutput()->GolbalReleaseDataFlagOn();

Then the data between each filter will be released after it is used.


Alternatively, it is possible to generate iso surfaces of extremely large 
volumes without thrashing.  VTK has the ability to stream the volume.  It 
will load/generate the volume and iso surface it a piece at a 
time.  Instead of vtkContourFilter,  use vtkImageMarchingCubes, or 
vtkSynchronizedTemplates3D.  The set the InputMemoryLimit (in kilobytes) of 
this iso-surface filter.


Charles.






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