[vtkusers] Volume Rendering

[Shanker Krishnan]

Hello,

I have a volume data whose data points density (Not the density value of the
data) decreases radially. Something like a log-polar plot in 3D. Can anyone
tell me how to render it. What data structure to use to represent the data.
And also how to vary the sampling distance in the raycastmapper at different
points for the same data. 
Also How can iread a volume data in StructuredGRID and render is using
VolumeRaycastmapper? 

Help  

Thanks in Advance.