Slow March

Bryan VanDeVen bryanv at
Thu Sep 2 10:54:47 EDT 1999

> I've been trying to visualize CT data for past few weeks.
> The code basically uses MFC with vtkBMPReader and vtkContourFilter with
> Win32OpenGLRenderWindow. There are about 4 Rendering Windows. The axial ,
> saggittal ,coronal and the surface rendering are displayed in each.
> Initially, I tried it with 70x70 Images which is about 1/8 of resolution on
> Pentium 300 Mhz with 128 Meg Ram on NT4.0. The program consumed all the
> memory and began to crawl..rather not respond, though the initial rendering
> took place.
> The system was upgraded to 550 Mhz with 384 MegRAM on NT4.0 and I used full
> resolution images..Same result. which is no result. The whole system was
> crawling and ran out of memory.

so full resolution images are 560X560??  How many slices?  If you have,
say, 200 slices, then a 560x560x200 array of 32bit floats or ints
already would consume 251MB just by itself without the program itself,
or any overhead or extra structures required to perform the processing.
And what a prodigious amount of processing will be required even for one
window, and you have four! 

Perhaps I am off the mark, and others might have some suggestions, but I
would say that if you really need to *interactively* visualize a dataset
that massive then you will never be able to do it on any PC type
platform, no matter what software you use or how much RAM you throw at
it.  Well, maybe a quad SGI vis540 with several gigs of RAM, but even
then I might have doubts, as that is truly an enormous dataset.  

Maybe you should just try the 70x70 on your new box....

Good luck,

Bryan Van de Ven
Applied Research Labs
University of Texas, Austin

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