[vtkusers] quetion

[XiaoJuan Hu]

hello,
everyone.
I get some CT data (both raw DS files and BMP format files)and I want to use vtkContourFilter to reconstruct the surface.I have two questions:
1) the raw data is 512*512. It's too large for the computer to process, how can I transfer them to 64*64? I don't know the ds file's format.
2) I also want to use the BMP file to do surface reconstruction. When I use the same program, the result 
  is obviously wrong. I wonder whether bmp file can be reconstructed.
thank you 

Xiaojuan Hu