[vtkusers] VolumePro1000

Lisa Avila lisa.avila at kitware.com
Thu Oct 31 13:15:44 EST 2002

Hello Farshid,

>thank you Lisa for your reply .
>I set blending mode to MIP. now I can use Volume Pro board.
>but I have these problems could you please tell me what is the problem ?
>1. by using VolumeMapper I could set RayCastFunction to mapper for MIP (or 
>compisit)and I had good results, in VolumeProMapper I use 
>"SetBlendingModeToMaximumIntensity" . the result is faster but it is 
>completely deferent ( in fact the result is not correct , in Ct Scan 
>Images it should display maximum intensity  but it display just first and 
>last slice of the image and between these two slice is blank.

I am not sure why you would see this - are you certain that your opacity / 
color transfer functions are correct? If you keep everything else the same 
and just switch mappers (between a ray cast mapper and a VolumePro mapper) 
do you see (approximately) the same image?

>2.  VolumeProMapper speeds up  process  time ,but to compare with VolView, 
>that is so slow why?

VolView will use the VolumePro mapper if it detects a board on your system. 
This may run faster or slower than the example you are working on since 
VolView may use different parameters for the size of the image (VolumePro 
1000 speed does depend on image size), the super sampling factors, etc.

>3.  I have some synthetic data ( binary and small for testing my codes ) 
>but still many times when I try to rotate the object I have this error:
>     volume data is too large for viewport.

Generally this error occurs when you are zoomed out too far from a volume. 
The VolumePro 1000 has a limitation on how far apart (in voxels) two 
neighboring rays can be - if you descrease your window size and/or zoom out 
farther from the volume you will exceed this limit which will cause the 
error message.


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